Performing Department
UC Davis Genome Center
Non Technical Summary
Our research aims to develop a new method for producing hybrid seeds in wheat and barley, which could significantly increase yields of these important cereal crops. We have previously discovered a genetic pathway in durum wheat that can induce conditional male sterility - the inability to self-pollinate - when disrupted. This sterility can be triggered by environmental factors like day length or temperature. In this project, we will apply advanced gene editing (CRISPR) and plant transformation techniques to disable the same key gene in diverse varieties of bread wheat and barley. This should render the plants male-sterile under certain environmental conditions, while allowing normal fertility under permissive conditions. We will grow the genetically modified wheat and barley plants and evaluate their male fertility across different temperature and day length regimes. This will allow us to optimize the environmental triggers for switching between male-sterile and fertile states. In-depth analyses will examine the developmental impacts in the plant's anthers (pollen-producing structures) resulting from this genetic disruption. The research team has expertise spanning small RNAs, plant genomics, reproductive biology, anther development, and hybrid seed production methods. Preliminary data suggests this innovative approach is feasible across diverse crop varieties. If successful, this environmentally-controlled male sterility system could enable widespread hybrid seed production for wheat and barley. This could boost yields by at least 15% - representing millions of tons of additional grain produced using the same agricultural inputs and land area. In summary, we aim to leverage a newly discovered genetic pathway to develop a robust technology for hybrid wheat and barley production, unlocking significant potential yield increases for these globally important cereal crops.
Animal Health Component
0%
Research Effort Categories
Basic
33%
Applied
34%
Developmental
33%
Goals / Objectives
We aim to assess the utility, in diverse inbred cultivars of bread wheat and barley, of a genetic pathway that we have demonstrated induces conditional male sterility when perturbed. The major deliverable would be discoveries that support production methods for hybrid seeds in these species and provide a roadmap for work on bread wheat. The approach is based on our previous NIFA-funded discovery that when 24-nt reproductive phasiRNAs are eliminated in durum wheat, the result is an environmentally-triggered male sterile phenotype - a response to photoperiod or temperature. The project will target the same gene in selected, diverse genotypes of the two Triticeae species, barley and bread wheat, using advanced, high efficiency CRISPR and transformation methods. Homozygous mutant lines will be grown under permissive and restrictive conditions to assess (1) whether they phenocopy our earlier observations, (2) whether there is evidence of background effects, (3) what environmental conditions are optimal for switching of male fertility, and (4) what are the developmental consequences in the anther of this genetic/environmental disruption to male sterility. The expertise of the PDs covers small RNAs, plant genomics, reproductive biology, anther development, and hybrid seed production. Our preliminary data suggest all aims are achievable. Success in developing hybrid seed production could increase wheat and barley yields by at least 15%, potentially more, representing an extra 16.3 and 50.9 million metric tons of barley and wheat (durum and bread), in Europe and North America, grown with the same inputs and footprint.
Project Methods
Here are the key methods that will be employed:CRISPR-Cas9 mutagenesisTarget conserved exonic regions of the DCL5 gene in diverse cultivars of wheat and grassesUse Agrobacterium-mediated transformation in collaboration with UC Davis Plant Transformation FacilityMutant generation and characterizationGenotype transformed plants to identify heterozygous dcl5 mutantsSelf-fertilize heterozygotes to generate homozygous dcl5 mutant lines, with at least two independent alleles per cultivarPhenotyping for male sterilityCharacterize wildtype accessions for male reproductive traits (fertility, pollen viability, anther staging) to establish baselinesScreen dcl5 mutants for male sterility under normal conditionsVary environmental parameters (temperature, photoperiod) to identify conditions restoring fertilityEvaluate pollen quality, fertilization, and seed viability under sterile vs fertile conditionsMolecular analysesUse microscopy to characterize timing of cellular defects in anther developmentPerform small RNA sequencing on anthers at different stages to assess depletion of 24-nt phasiRNAs in mutants under sterile vs fertile conditionsField trialsEvaluate utility and consistency of conditional male sterility across diverse genotypesAssess potential for applications in hybrid seed production of small grains