W3168: Environmental and Genetic Determinants of Seed Quality and Performance
(Multistate Research Project)
W3168: Environmental and Genetic Determinants of Seed Quality and Performance
Duration: 10/01/2014 to 09/30/2019
Statement of Issues and Justification
THE NEED, AS INDICATED BY STAKEHOLDERS: Our stakeholders are those that produce and use seeds. These stakeholders need high quality seed to produce food, feed, fiber, bio-fuel, and other plant products. Our stakeholders also require validated information useful for the production of high quality seeds. Stakeholders include academics, commercial and government sector scientists, seed producers, agronomists, horticulturists, land and natural resource managers, educators, extension agents, government agencies, and all industries that deliver seed to growers. A critical goal of this multistate project is the education of current and future generations of seed scientists needed to maintain U.S. leadership and expertise in the seed industry. Maintaining this high standard has made the U.S. crop seed industry the recognized leader in the world with annual sales growing from $56 to $97 billion during 2007 to 2010 (Anon. 2008; 2012: Table 821, 855). It is also important to extend similar standards and enhancements to other species with rising economic potential. Not all species respond equally to the breadth or intensity of available seed technologies. Therefore, research is needed to achieve the best balance of treatment cost and seed performance appropriate for the stakeholders' desired uses. Increasingly, crop protection and other traits are delivered via the seed with corresponding increases in cost. Higher seed costs place greater demands and expectations on seed performance. Each farmer is sensitive to the need for rapid and uniform seedling emergence because it is the foundation of successful stand establishment that greatly affects potential yield.
An emphasis of this new project is placed on maximizing seed quality and performance of seeds to meet the demands of agriculture. In addition, the physiological quality of seeds is of increasing importance to biofuel crop and re-vegetation programs, where seeds are often planted under adverse seedbed conditions. In these cases, establishment and survival of the seedlings is the most crucial step. Moreover, many of these species, including native species, have innate dormancy that results in sporadic germination and establishment. Finally, increased costs associated with rapid advances in biotechnology and genomics underscore the importance of maintaining all germplasm resources indefinitely into the future. Genetic resources preserved in seeds will ensure diversity upon which future advances in agricultural productivity will depend. Germplasm preservation assumes renewed importance since all genes are now potentially available for utilization in crop improvement. Seeds also deliver plant technology to the field. Farmers are required to invest greater capital in seeds that incorporate seed treatments, such as priming, coating, or value-added traits. The benefits of these sophisticated technologies can only be utilized if seed performance is optimized.
Both domestic and foreign seed companies maintain production and research facilities at various locations throughout the U.S. due to the climatic diversity, the ability to produce high quality seeds, skilled farmers who specialize in seed production, and the size of our domestic markets. Seeds are increasingly produced in one location and marketed in another. This interstate and global commerce requires a high quality product capable of withstanding the rigors of shipment and storage, and performing reliably under a diverse range of field conditions. Meeting these demands requires cooperative research efforts in both production and utilization locations.
THE IMPORTANCE OF THE WORK, AND WHAT THE CONSEQUENCES ARE IF IT IS NOT DONE: U.S. agriculture is the most competitive and productive agricultural industry in the world and is highly dependent on the quality of seeds utilized. Risk exposure to poor seed quality, even in the background of superior germplasm, is enormous, and would result in disruptive economic consequences accompanying yield reductions, fewer exports, higher food prices, and localized commodity shortages. Moreover, an understanding of seed dormancy is needed to regulate germination when desirable after sowing, but to prevent germination while seeds are on the mother plant. The concept and provision of seed quality is well defined for most familiar agronomic and horticultural crops, but by no means optimized or evenly applied across species. Adoption of seed and seedling quality metrics is important for all utilized plant species. Since such metrics are necessarily species-specific, research is needed at the species level, as well as at the cellular level, where many genetic and environmentally responsive biological processes share common underpinnings but diverse effects. Exploiting traditional or non-traditional species for novel uses, such as those being developed for bio-fuels or high value oils, requires examination (or re-examination) of seed quality metrics to ensure growers and producers have the best chance of providing a high quality product to the consumer. Interruptions or inefficiencies in this supply chain have obvious economic consequences and can be partially ameliorated by careful scientific attention to seed quality and performance. Loss of genetic resources and diversity through habitat destruction and supplanting traditional varieties and local species could have a long-term impact on the progress of plant improvement.
This multi-state project includes the key Seed Scientists in academia that formulated three interrelated objectives that are relevant to the breadth of the US seed industry. The three objectives are: 1) identifying key factors involved in the enhancement or loss of seed quality, 2) eliminating seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment, and 3) enhancing seed vigor and germination in agronomic and ecological species for improved stand establishment. There are 16 participating institutions with 13 Land Grant Universities and 3 USDA-ARS locations. This multi-state project is the only vehicle that facilitates these seed scientists to work in a cooperative manner to address key seed problems in a systematic fashion. There is no other agency or organization in the US that integrates the depth and breath of expertise to tackle these objectives. Therefore, one consequence is that future seed research would be done by individuals on a very narrow topic that may have little relevance to the larger array of seed crops and species.
THE TECHNICAL FEASIBILITY OF THE RESEARCH: We use the latest technologies, and develop new techniques, to investigate the central questions of seed biology and seeds as delivery systems. In most cases, the technical feasibility of the research procedures is proven as standard practice in the case of field-oriented research, or as an extension of established genetic, biochemical, and physiological principles. Results from genomic and proteomic approaches will yield new insights for practical application; however, there will likely be a time lag between discovery and adoption beyond the scope of this proposal.
Objective 1 - Identifying key factors involved in the enhancement or loss of seed quality. This effort integrates research activities in a continuum from seed development through post-harvest losses in storage. Specific topics include seed development, desiccation tolerance, and aging in storage.
Objective 2 Eliminating seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment. This objective focuses on two interrelated issues in seed biology: pre-mature sprouting in cereals and other species and the identification dormancy mechanisms to manipulate germination.
Objective 3 - Enhancing seed vigor and germination in agronomic and other species for improved stand establishment. The emphasis of this objective is on post-harvest technologies to assess and enhance performance. Seed quality assessment can be conducted on a single-seed basis to characterize seed lot performance. Seed coating technologies are used for seed treatment application and to enhance plant performance and have broad application in agriculture.
These objectives are not mutually exclusive, but represent the continuum between basic and applied research in meeting seed user needs for the future. We are one of the longest running multistate working groups in the USDA with the formal beginning as a Regional project in the early 80s. Our members are internationally recognized authorities on seed science, with many demonstrated accomplishments including two major international seed symposia since 2000, dozens of books and book chapters, hundreds of peer reviewed journal articles, and deployment of a series of on-line educational courses. Within the present group, at least 30 collaborations have yielded demonstrated results and many additional projects are ongoing and planned. The future feasibility of achieving successful results through continued multistate collaboration is assured, given the prominence and productivity of the groups members (see Attachments).
THE ADVANTAGES OF DOING THE WORK AS A MULTISTATE EFFORT: This Regional Research Project was initiated in 1983 in the Western Region due to the extensive seed production in the region. However, seed production occurs nationwide. The diversity of seed production throughout the U.S. and the lack of any other regional projects devoted to seed biology or technology led the project to expand to encompass seed researchers across the U.S. Consequently, this project has played a critical role in coordinating diverse public seed biology research at the national level.
Despite the diversity of species and locations involved in this project, fundamental aspects of seed biology are common to all. Measurement and enhancement of seed quality present challenges and opportunities regardless of the species or location. It is precisely by examining seed biology from diverse perspectives, from the whole plant to the molecular, that the entire biological picture becomes clearer and specific applications can be devised. The continuation of this project is essential to the mission and goals of ensuring quality seed production, maintaining seed conservation, and training of seed professionals for the generations to come.
Developing solutions to provide an abundant supply of high quality seeds for agriculture is essential for maintaining/improving food security for the United States. Seed problems are complex, requiring seedcentric experience and skills, equipment, and methodologies. Utilizing a multistate effort by drawing on the expertise of specialized research scientists is the most efficient approach to addressing these issues on a national level. Despite recent advances in understanding the molecular biology of seeds, relatively little is known about how seeds germinate, why some seeds germinate better than others, why some seeds germinate before harvest, what causes dormancy, and why seeds die in storage. New fundamental knowledge about mechanisms underlying seed development, germination, and storability is required to solve these challenges. Seed performance must be improved: (1) for the U.S. to maintain our global competitiveness as an exporter of seeds as propagules; (2) to increase the efficiency of food production to preserve environmental quality; and (3) to take full advantage of advanced technologies. A clearer understanding of how environmental factors affect seed performance in natural and agricultural ecosystems is needed to ensure the continued vitality of native plant populations and the productivity of cropping systems. Successfully completing the stated objectives will provide not only an increased understanding of the factors that influence seed biology, but also practical methods to improve seed performance in the field.
There is a documented decline in the number of seed scientists graduating from land-grant universities. Moreover, a decline in the number of seed scientists charged with educating the next generation at these institutions also occurs. This is creating a gap of expertise in the seed industry and a declining capacity to meet this need. For example, 44 seed science faculty in 16 land-grant institutions graduated 183 students between 1990 and 2000, but declining support resulted in only 35 students trained in seed science from 2000 to 2005, with a loss of nine faculty and three states with formerly active seed science programs (TeKrony 2006). With declining in-state programs, it is critical to view seed science research in a national context. Rapid progress in basic seed biology research using model species also enables more opportunities for collaborations among seed biologists in multiple states. Seed industries require continuing university research to address complex seed physiology problems that impact product development. The advantage of a multistate project is to integrate individual activities and to leverage information gained from current state programs across the wide range of species and problems faced by seed producers and users nationwide. This multistate project serves as the only mechanism to unify seed science research across the U.S., bringing the national seed science expertise to bear on problems of local and regional significance.
WHAT THE LIKELY IMPACTS WILL BE FROM SUCCESSFULLY COMPLETING THE WORK: The projected impacts from completing this proposed work as a multistate project are enormous. One major impact of the proposed work results from coordinated research results across species and applications to generalize the innate biology of seeds as a first step to deploying improved technology to the end user. Progress on understanding the intrinsic mechanisms involved in seed development and limiting stand establishment is expected, as are the role(s) of specific genes, the environment, and their interactions. We expect results to increase efficiency and cost effectiveness of crop establishment and habitat restoration. Results will further our understanding of biological processes involved in seed dormancy and longevity, and germplasm preservation and the maintenance of species diversity. The transfer and development of seed technologies for the establishment of bio-fuel is essential for their widespread adoption, and progress are envisioned through collaborative efforts among members of this multistate project.
Related, Current and Previous Work
RELATIONSHIP TO OTHER PROJECTS: A search of the NIMSS database revealed two active multistate projects that peripherally deal with seeds: S1051 (Sustainable Practices, Economic Contributions, Consumer Behavior, and Labor Management in the US Environmental Horticulture Industry) and NC213 (Marketing and Delivery of Quality Grains and Bio-Process Co-products). There is no significant overlap between the objectives of the proposed project and other existing research projects. The NIMSS database review shows that the discipline of Seed Biology is multi-faceted and that a wide range of expertise is required to pursue fundamental scientific advances. More importantly, the database review confirmed that W-3168 members are the primary source of active research that supplements and extends seed science knowledge nationwide.
Similarly, a recent CRIS search identified 1,431 projects using seed, seedling, or germination in the project description. However, only one currently active project (Accession #0219280, South Dakota State University) dealt tangentially with germination and viability testing of some native species. The focus of the South Dakota project was identifying bioactive compounds of selected species.
SYNOPSIS OF PREVIOUS ACCOMPLISHMENTS: Research was conducted under W-2168 that termed on September 30, 2013. A majority of the seed scientists from W-2168 will continue on W-3168 representing CA, FL, IA, KY, LA, MI, NY, OH, OR, SD, TX, VA. Four new states will join W-3168 representing CO, MS, OK, and WA. Annual reports from W-2168 meetings document outcomes and see Attachment 4 W-2168 Refereed Publications 2008-12.
Some examples of prior impacts from this project include the identification of genes and mechanisms specifically associated with stress tolerance during germination, the development and commercialization of new methods to assess seed quality, the identification of mechanisms associated with seed deterioration and methods to delay or prevent this process, methods to alleviate seed dormancy, and determination of uptake of systemic seed treatments. This new project will extend and focus these approaches, and by developing greater insight into the underlying genetic and physiological mechanisms, will enable increasingly powerful and effective technologies for improving, assessing and preserving seed quality. Seeds have increasingly become the delivery system for multiple biological and chemical technologies; therefore, expectations for and demands on seeds will require corresponding attention to maintain all aspects of seed quality. New discoveries, such as genes associated with seed dormancy or responses to enhancement treatments, can potentially provide synergistic improvements to seed quality by combining genetic and technological approaches. Similarly, studies on seed coat permeability will enable more effective use of seeds to deliver crop protectants, greatly reducing the amounts of chemical pesticides applied per acre while increasing efficacy. Seeds represent a critical input into agriculture where multiple technologies can be combined for increased efficiency and reduced environmental impact.
Identifying key factors involved in the enhancement or loss of seed quality.
Eliminating seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment.
Enhancing seed germination in agronomic and native species for improved stand establishment.
MethodsMethods for Objective 1: Identifying key factors involved in the enhancement or loss of seed quality. There are 14 participating states in this objective: CA, CO, FL, IA, KY, LA, MI, MS, OH, OK, OR, SD, VA and WA. The seed biology models examined will include agronomic and vegetable crops, and other species on key seed research topic areas. Information gained in one of these topic areas, species groups, or methodological approaches is often directly applicable to other species. Objective 1.1: Environmental, physiological and genetic factors regulating the development of seed quality and tolerance to desiccation in both orthodox and recalcitrant seeds. Approaches from the field to the molecular level will be employed to explore the issues identified in this sub-objective. With respect to environmental conditions during seed development, IA will determine the effects of soil fertility and environmental stress during soybean seed development on seed composition, vigor and longevity. Drought and heat conditions during soybean pod filling stage (R5 to R6) may cause flat soybean pods and lower the seed quality. VA will explore the influence of irrigation treatment during R5 and R6 stages on seed composition, germination and field emergence using drought tolerant and sensitive soybean varieties. OH will investigate the sensitivity of seeds of various ornamental species of Asteraceae to manipulation of light quality during seed maturation since it has been found that wavelengths of light perceived during seed maturation have significant effects on subsequent seed quality in lettuce (Contreras et al., 2008, 2009). In both cases, the goal is to identify environmental factors that can be modified to improve seed quality and performance. Seed quality has a major genetic component, and to address this, MS will study the genetic and epigenetic regulators controlling grain filling during rice seed development that contributes to seed quality. Also in rice, SD will initiate a new project to elucidate genetic and molecular mechanisms of seed longevity. SD has developed extensive genetic resources in rice for analyzing seed quality traits and has demonstrated success in identifying QTL and specific genes associated with such traits (e.g., Gu et al., 2010). MI is conducting similar studies in sugar beet and has developed recombinant inbred lines differing in seed vigor. MI will characterize global gene expression during sugar beet seed development and germination to enable genetic analyses utilizing these lines and other genotypes differing in seed vigor. KY will characterize the transcriptomes and proteomes of Arabidopsis seeds in relation to the development of potential seed longevity, identifying candidate genes that can be tested in rice, sugar beet and other species. OK will study the role of the FT-D3 gene in wheat, a homolog of a related gene in Arabidopsis, in regulating seed development and maturity in wheat. This combination of genetic and molecular approaches, utilizing both model systems and crop plants, will further elucidate the genes and pathways necessary for the development of high quality seed. Plant hormones, particularly ABA and GA, are critically important regulators of seed development. ABI3 is a transcription factor that plays a central role in seed development. KY will identify the promoters to which ABI3 binds and therefore the genes that it regulates. Since ABI3 is itself regulated by ABA, this will clarify the regulatory network controlled by ABA. On the other hand, GA is involved in both seed germination and stem elongation. WA will investigate this relationship in wheat, where precocious germination associated with GA can lead to preharvest sprouting and loss of seed and grain quality. CA is pursuing similar studies in lettuce to understand the relationships of ABA and GA in regulating seed development and germination in response to temperature. These studies will be advanced by the contributions of OR, who has developed and demonstrated an inducible gene expression system that can alter hormone levels in vivo during seed development to influence subsequent seed germination capacity (Martinez-Andújar et al., 2011). These projects are employing genetic and molecular methods, including mutants, transgenes, RNAi silencing, miRNAs and inducible expression systems to investigate the regulation of seed development and quality. The physiological and metabolic factors that influence seed quality will also be studied. VA will use peanut breeding and soybean lines and existing cultivars differing in oleic and linoleic acid content to establish whether a relationship exists between fatty acid content and low temperature germination performance. KY will use Arabidopsis mutants to elucidate the influences of isoaspartate and light on seed longevity. In addition, KY will assess the interactions of late embryogenesis abundant (LEA) proteins with other proteins in enhancing seed desiccation tolerance and longevity. Objective 1.2: Mechanisms of seed deterioration and methods for optimizing seed storage conditions to extend seed longevity. LA will explore the cause of recalcitrant seed death in Spartina alterniflora along with suggestions for seed treatments and/or breeding solutions to improve its longevity in storage. In cooperation with CO, LA will also assess comparative mechanisms of desiccation tolerance in grass seeds. Furthermore, these researchers will investigate the mechanisms of seed aging using analysis of head-space volatiles collected from stored seeds. While oxidation is known to be involved in seed deterioration, such analyses of oxidized volatile products could identify specific targets associated with loss of seed viability. In addition, FL and CO will collaborate to use biophysical methods (e.g. Differential Scanning Calorimetry and Dynamic Mechanical Analysis) to examine changes occurring in aging seeds. Equipment necessary to carry out biophysical research is located at CO. FL and CA will jointly investigate the respiratory response of aging seeds using the ASTEC Q2 respirometer located in CA (described in Objective 3.2). Methods for Objective 2: Eliminating seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment. There are 8 participating states in this objective: CA, KY, LA, MS, OK, OR, SD and WA. Seed dormancy may reduce germination uniformity and consequently lower the quality of seedling establishment, while lack of seed dormancy may cause pre-harvest sprouting in cereal crops when cool rainy conditions occur before harvest. Therefore, major issues being addressed include: Objective 2.1 Genetic, physiological and molecular mechanisms regulating pre-harvest sprouting. Pre-harvest sprouting research will focus on rice and wheat crops and contributing states will share assessment protocols for seed dormancy and germination, plant materials (mutant lines) for hormone research, and latest research information. SD will continue to characterize candidate genes isolated from the narrowed qSD12-containing regions for molecular functions regulating the development of embryo dormancy by complementation, high throughput RNA-sequencing, and improved marker-assisted genetic approaches. SD will also clone the qSD1-2 and qSD7-2 seed dormancy QTLs associated with GA biosynthesis and signaling, respectively, in rice (Ye et al. 2010) using fine mapping, sequencing, T-DNA insertion and complementation analyses, and molecular biology approaches. SD and MS share in development and management of hybrid lines and mapping populations for seed dormancy research. Mutant lines for several known genes of GA biosynthesis/signaling pathways provided by WA will also be crossed with the natural mutants isolated from the qSD1-2 and qSD7-2 loci to determine the role of the GA hormone in regulating dormancy development and release in rice. WA will determine the roles of ABA and GA hormone signaling in regulating pre-harvest sprouting and seedling emergence in wheat. This lab will follow cereal seed storage, after-ripening and seed plating assay protocols provided by LA. The relation between expression levels of the GA receptor gene GID1 and degrees of seed dormancy will be determined in Arabidopsis and wheat. Wheat ABA-hypersensitive mutants have more dormant seeds than ABA-insensitive mutants (Schramm et al. 2010; Schramm et al. 2012 ). Thus, the ABA-hypersensitive mutant Zak ERA0 will be mapped, cloned and molecular characterized, and the mutant gene will be deployed to reduce the risk of pre-harvest sprouting in white grain-colored wheat. OK will identify QTLs for seed dormancy in wheat using a population of 282 recombinant inbred lines and backcross populations. These populations will be grown under temperature- and light-controlled conditions and the degree of seed dormancy evaluated with seeds treated with cold, heat, and room temperature (control). Homologues of the Arabidopsis MFT gene reported to induce seed dormancy in low temperatures will be sequenced to determine their allelic variation in wheat. The transcription level of the homologues in different temperatures and interacting proteins of the dormancy gene will also be determined to elucidate its regulatory mechanisms in wheat. The populations will also be used to determine the intersection between vernalization and seed dormancy in wheat. OR and WA are collaborating to extend the GeneSwitch system from Arabidopsis to wheat and sorghum to develop novel technologies to improve resistance to pre-harvest sprouting. These labs share: methods for protein and mRNA isolation, anti-bodies and transgenic lines carrying GUS fusion constructs. The GeneSwitch technology will be used to engineer hormone levels in developing, mature, and imbibed seeds. The chemical ligand methoxifenozide will be applied to developing or imbibed seeds to alter hormone balances. In addition to the GeneSwitch approach, a system to cause spontaneous overexpression of hormone metabolism genes will be created using seed-specific promoters. Database search and a reverse transcription (RT)-PCR approach with degenerate primers will be used to isolate wheat and sorghum genes associated with hormone metabolism and signal transduction. Those genes will be expressed using a chemically inducible gene expression system or spontaneous over-expression using seed-specific promoters. Possible interactions of seed dormancy-associated genes will be tested using an effecter-reporter assay in a transient system, such as Nicotiana bethamiana leaf infiltration assay. Objective 2.2 Genetic, physiological, and molecular mechanisms regulating the development and alleviation of seed dormancy. A ChIP-CHIP technique will be used to conduct a genome-wide scan for binding sites of the transcription factor ABI3 and use micro expression arrays to examine genes responsive to ABI3 binding in seeds at the times of late development and prior to and after imbibition in Arabidopsis. KY will also use techniques of DNA-immobilization on beads, phage display and affinity selection to assess DNA tracts encoding transcription factor motifs for which heteroduplexed proteins are required to bind. KY and CA will collaborate to analyze promoter differences among alleles of NCED4 genes in lettuce. They are working to validate the phage display method developed by KY to identify transcription factors that bind to specific promoters. In addition, CA will characterize lettuce and Arabidopsis mutants for altered ethylene biosynthesis or sensitivity, as well as high temperature germination capacity. Bulked segregant analysis will be combined with high throughput genotyping utilizing DNA sequencing to identify candidate genes associated with altered phenotypes or mutant genotypes in lettuce, (Laitinen et al. 2010; Schneeberger et al. 2009). Once candidate genes are identified, gene expression analysis, comparison with Arabidopsis mutants and transgenic over-expression and silencing will be used to confirm their roles in regulation of germination. To analyze maternal effects on seed dormancy, recombinant inbred line populations will be grown to produce seeds at low (20-25°C) and high (30-35°C) temperatures in greenhouses and also in diverse field environments. Hydrotime and hydrothermal time analyses will be conducted as previously described (e.g., Alvarado and Bradford 2005). QTL analysis will be used to identify loci associated with the phenotypic variation in seed dormancy evaluated in different growth environments. KY will continue the research on physical dormancy (PY) to elucidate the function of seed water gap in those families where the water gap system has not been adequately described. In addition, the mechanism controlling PY in the Geraniaceae will be studied in detail. Treatments (dry or wet heat) will be applied to release seeds from PY. Dye tracking experiments will be used to determine the initial point of water entry (water gap) into the seed. Morphological and anatomical studies will be conducted to identify the type and putative mechanism of the water gap using EM, light microscopy and paraffin sections on seeds before and after PY is broken. Methods for Objective 3: Enhancing seed germination in agronomic and native species for improved stand establishment. There are 10 participating states in this objective: CA, CO, FL, IA, MI, NY, OH, OR, TX and VA. This objective has three related but distinct subsections: 1) understanding the physiological and genetic basis for seed vigor; 2) seed technology methods to critically assess seed quality; and 3) seed treatments to enhance germination especially under conditions of abiotic stress. Objective 3.1 Understanding the physiological and genetic basis for seed vigor. The physiological parameter selected for study under this objective is seed respiration. CA will investigate the relationship of seed respiration rates to seed quality using the ASTEC Q2 instrument. Indices derived from these data will be compared to other vigor tests. Analysis methods have been developed to utilize population-based threshold models to analyze respiration data, and these will be utilized to extend the applications of the Q2 to seed quality assessment. Analyses of respiratory metabolism will be conducted for seeds in specific respiratory states identified in the Q2. For isotherm studies, seeds will be equilibrated at a range of established relative humiditys using saturated salts. Seeds will be either pre-hydrated or pre-dried to determine whether they are on their sorption or desorption isotherms. They will then be sealed and aged for various periods at 40 or 50°C and tested for germination and viability. Research is performed in cooperation with CO and FL. MI will use a genetic approach to study gene expression during seed development and germination to better define seedling vigor and the associated transcriptomics for gene discovery. Reference transcriptomes will be obtained from the sugarbeet inbred 'C869' at seven specific stages of early season growth, 6 hours post-imbibition of seeds, 48 hours post-imbibition (at the time of radicle protrusion), and with roots at 1.5-, 3-, 7-, and 10-weeks after emergence. Combined leaf and crown tissue will be assayed for the later four waypoints. Choice of these time points is dictated by previous work (Naegele 2010; Trebbi and McGrath 2009), and appears to cover the major transitory phases of seedling to adult growth. The approach will be via RNA-Seq using the Illumina HiSeq 2000. One hundred base pair paired-end sequences will be aligned and assembled using the C869 draft genome sequence and the Tuxedo suite of software tools (Bowtie, TopHat, and Cufflinks). Recombinant inbreds have been developed that differ in seedling vigor. Selected RILs, from field phenotypic observations, will be used to test hypotheses relating gene expression to trait expression. Not all RILs will be tested, but rather those showing extremes of phenotypes present within a RIL population. Molecular phenotypes of selected RILs will be determined /confirmed via qPCR using three biological replicates and two technical replicates per treatment. Objective 3.2 Seed technology methods to critically assess seed quality. VA will concentrate on Objective 3.2, using Fourier Transform Infrared Spectroscopy (FTIR) to develop a rapid, nondestructive detection method to identify seed pathogens and seed viability. VA and IA will couple FTIR equipment with high-speed seed sorting equipment located in IA to test the rapid removal of unwanted seeds from a lot. NY will collaborate with VA and IA on FTIR technology on selected cereal crops. Objective 3.3 Seed treatments to enhance germination especially under conditions of abiotic stress. Seed and seedling conditioning treatments aimed at improving stand establishment for high value vegetable crops will be evaluated by TX. Treatments with plant growth regulators - PGRs (ABA, GA3, ethylene, biostimulants) will be investigated for their efficacy to regulate shoot and root growth, enhance stress tolerance and plant recovery after transplanting. Treatments will include various concentrations and timing of applications which will be evaluated under drought and heat stress. Standard growth measurements will be performed for shoot growth, chlorophyll content and gas exchange. Root growth will be evaluated using a scanning technique with an image analysis system. During the second phase of the project, the involvement of PGRs in regulating the antioxidant defense mechanism under drought and heat stress will be explored. Combinations of bio-control, PGR and priming treatments will be tested by OH to improve germination and emergence of a range of vegetable and flower species. Computer-aided imaging of young seedlings will be employed to assess treatment effects. Greenhouse and field studies will evaluate the potential for treatments to mitigate challenges to seedling establishment. Seed coating technologies will be adapted and utilized on a wide range of crop and non-crop seeds. Coating technology can serve as a carrier of plant protectants and to facilitate sowing. NY and IA have state-of-the-art coating equipment that will be used for collaborative projects for the application of active compounds to enhance germination. Efficacy of seed treatments for pest will conducted in collaboration with W-3168. Biochar, created by burning wood biomass in an oxygen-started kiln will be developed as a seed treatment to enhance plant growth will be studied by OR and NY. Low-phytate soybean helps to improve animal feeding value though increased digestion ability of animals and reduce negative environmental impact by lowering phosphorus released into waterways. However, low-phytate soybeans do not emerge as well as normal- phytate soybeans. Phosphorous-coated low-phytate soybeans may be one effective solution to this production issue and will be examined by VA and NY. NY will develop seed agglomeration technology for pelleting multiple seeds into the same propagule, and seed coat permeability research will be conducted to assess systemic seed treatment uptake.
Measurement of Progress and Results
- Research activities will continue to produce peer-reviewed journal articles (e.g. > 150 peer-reviewed articles from 2008-12), books, book chapters, edited books, conference proceedings, patents, educational materials, abstracts, and public outreach materials
- Information regarding gene networks involved in stress responses, dormancy, germination, disease-resistance, and storage longevity
- Practical seed science knowledge for policy and decision making within industry, governmental, and non-governmental agencies
- New seed coating, germination equipment, germination enhancement, and seed storage technologies
- New methods to identify seed-borne pathogens
Outcomes or Projected Impacts
- Molecular biology research will advance understanding of post-transcriptional regulation of gene expression in seeds
- Understanding of gene expression patterns in developing, dormant and germinating seeds will facilitate development of new hybrids resilient to environmental changes
- Restoration practitioners and seedling producers can better plan and coordinate in terms of seeding activities for restoration of degraded lands.
- Conservation practitioners can adapt methods for ex situ activities.
- Changes in seed technology and equipment will improve research opportunities, reduce seed losses and associated costs, increase yields, facilitate management of seed inventories, and increase seed industry profits
- Identification of seed borne pathogens will protect animal and human health, increase efficiency within supply chain, and limit seed losses
Milestones(2015): Objective 1: To identify key factors involved in the enhancement or loss of seed quality by 2019 desiccation tolerance proteins in Spartina must be characterized by 2015. Objective 2: To eliminate seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment by 2019 Arabidopsis transgenic lines expressing dormancy-associated genes must be characterized by 2015. Objective 3: To understand the physiological and genetic basis for seed vigor by 2019 a seed agglomeration technology for sowing multiple seeds in one propagule must be develop by 2015. To increase membership by 2019 invitations to participate in the project must be sent to potential members at university and ARS facilities by 2015.
(2016): Objective 1: To identify key factors involved in the enhancement or loss of seed quality by 2019 the role of fatty acids in determining peanut seed quality must be elucidated by 2016. Objective 2: To eliminate seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment by 2019 genes and regulatory networks involved in lettuce thermodormancy must be described by 2016. Objective 3: To understand the physiological and genetic basis for seed vigor by 2019 seed sorting and free space analysis techniques must be evaluated by 2016.
(2017): Objective 1: To identify key factors involved in the enhancement or loss of seed quality by 2019 comparisons of protein profiles associated with the loss of rice seed desiccation tolerance must be conducted by 2017 Objective 2: To eliminate seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment by 2019 expression of GID1 via regulation by after-ripening or cold stratification must be verified by 2017. Objective 3: To understand the physiological and genetic basis for seed vigor by 2019 a high throughput FTIR system for sorting seeds must be formed by 2017.
(2018): Objective 1: To identify key factors involved in the enhancement or loss of seed quality by 2019 mutants for roles in rice seed and endosperm development must be described by 2018. Objective 2: To eliminate seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment by 2019 the GeneSwitch system must be extended from Arabidopsis to wheat by 2018. Objective 3: To understand the physiological and genetic basis for seed vigor by 2019 seed enhancements to improve plant growth and development under stress must be tested by 2018. To identify new research objectives requiring strategic collaboration by 2019 a workshop during an annual meeting must take place by 2018.
(2019): Objective 1: To identify key factors involved in the enhancement or loss of seed quality by 2019 QTLâ€™s for seed longevity in rice must be identified by 2019. Objective 2: To eliminate seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment by 2019 synthetic mucilage that can enhance seed germinability must be developed by 2019. Objective 3: To understand the physiological and genetic basis for seed vigor by 2019 seed quality test protocols using the Q2 instrument must be realized by 2019. To enhance outreach, foster collaboration between members and industry, and increase membership by 2019 a symposium must be organized by 2019.
Projected ParticipationView Appendix E: Participation
The members of W-3168 comprise a group of highly dedicated seed biologists who excel in the communication of their research findings. All members of the W-3168 project are active participants in seed research at universities and federal facilities throughout the country. They provide leadership in this vital area through undergraduate and graduate instruction, as well as by mentoring graduate and undergraduate research. A number of our members conduct extension workshops to provide the seed industry with a thorough orientation to seed biology fundamentals, as well as the latest cutting edge results. For example, the Seed Biotechnology Center at UC Davis offers courses in seed biology and breeding technologies to the public and seed professionals that incorporate the latest information generated through W-3168 (http://sbc.ucdavis.edu). The Iowa State Seed Center also offers regular courses and workshops in topics related to seed biology, conditioning and marketing (http://www.seeds.iastate.edu/). VA and CA will write a new textbook on Vegetable Seed Biology, Production and Quality. Moreover, VA has been a leader in utilizing distance education to deliver seed courses to national and international student groups.
As documented in the projects annual reports, W-3168 members regularly publish their finding in top-tier, peer-reviewed journals, targeting both the general plant biology and seed biology communities. W-3168 members are also active participants and presenters at various professional society annual national/regional meetings, as well as at the major workshops and symposia sponsored by the International Seed Science Society and the International Society for Horticultural Sciences. W-3168 members serve on journal editorial boards and/or as ad-hoc manuscript reviewers, publish books and book sections on seed biology (Allen et al. 2007; Bewley et al. 2012; Bradford and Nonogaki 2007; Perry and Yuan 2011; Pluskota et al. 2011), and obtain patents for intellectual property (Frey et al. 2009; Madsen et al. 2010; Taylor et al. 2011). To date there are 40 labs that have links to their home pages on the American Seed Research Alliance (ASRA) web site (http://dept.ca.uky.edu/asra/). Furthermore, W-3168 will plan to organize a symposium in conjunction with scientific organizations and industry groups, as was done in 2007 with Translational Seed Biology: From Model Systems to Crop Improvement at UC Davis. This symposium resulted in a special issue of Plant Science (Bradford and Harada, 2010).
W-3168 members also interact with seed industry groups on a regular basis. For example, FL works with native seed industry members to develop collaborative research projects that enhance the emerging seed production industry in this region. In California, an organization called Seed Central has been organized specifically to enhance communication and partnership between UC Davis and the surrounding seed industry (www.seedcentral.org). Seed Central is a collaboration between the Seed Biotechnology Center (directed by W3168 member Bradford) and SeedQuest.com (the premier website of the global seed industry). This organization sponsors monthly networking events and facilitates collaborative public/private research related to seeds and crop improvement. It also initiated an annual Vegetable Research and Development Forum to discuss research needs and common issues in the vegetable seed industry, at which W3168 members Taylor (NY) and Bradford (CA) presented their research programs.
Organization will follow recommendations for the Standard Governance for multistate research activities including the election of a Chair, a Chair-elect, and a Secretary. All officers are to be elected for three year terms, as follows: a Secretary will be elected annually, then become Chair-elect in the second year, and Chair in the third year. Administrative guidance will be provided by an assigned Administrative Advisor and a CSREES Representative. The W-3168 welcomes and encourages participation of expert seed biologists affiliated with State Agricultural Experiment Stations, the Agricultural Research Service, and colleges or universities, as is consistent with the Multistate Research Fund mission of the Agricultural Research, Extension, and Education Reform Act of 1998.
Alvarado V, Bradford KJ (2005) Hydrothermal time analysis of seed dormancy in true (botanical) potato seeds. Seed Science Research 15:77-88
Anon. (2008) The 2008 Statistical Abstract. http://www.census.gov/prod/2007pubs/08abstract/agricult.pdf
Anon. (2012) The 2012 Statistical Abstract. http://www.census.gov/compendia/statab/2012/tables/12s0855.pdf
Bradford, K.J., and Harada, J.J. (2010) Introduction to Translational Seed Biology: From Model Systems to Crop Improvement. Plant Sci. 179, 553-553.
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Ye H, Foley ME, Gu XY (2010) New seed dormancy loci detected from weedy rice-derived advanced populations with major QTL alleles removed from the background. Plant Science 179:612-619