Location: Crop Germplasm Research
Project Number: 3091-21000-044-004-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Mar 1, 2020
End Date: Dec 31, 2020
Objective:
Cotton (Gossypium spp.) is the most important fiber crop and a potential oilseed crop. Hybrid cotton takes advantage of heterosis in the production of natural fiber and oilseed and protein among other priority traits. The objective of this research is to develop an effective genetic system to produce hybrid cotton seed that can reduce the costs of hybrid seed propagation and make it practical for the U.S. cotton growers to utilize the desirable hybrid vigor for increased fiber and seed production.
Approach:
This proposed research project involves a series of experiments to be performed at USDA Agricultural Research Service. The studies build upon our existing knowledge and research experience to investigate genetic male sterility for hybrid cotton seed production. In this proposed project, we will curate and analyze all male reproductive genes currently available in higher plants. Sequence homology of the candidate genes will be searched in upland cotton genome. At least one dozen candidate genes will be selected to design the guide RNAs for target gene knockout in elite upland cottons using the CRISPR/Cas9 technology. Alternatively we will use RNAi technology to knockout the function of these target gene transcripts. A multi-target vector will be used to construct gene-editing assembly. The constructs will be validated by transient assays, and the positive plasmids will be transformed into the selected cotton accessions in collaboration with a Cotton Incorporated sponsored facility. Then we will employ the developed tools to study the function of target genes associated with nuclear male sterility as well as other priority traits (fiber, seed, biotic and abiotic). The resulting male sterile mutants will be regenerated and evaluated for reproductivity of aborted pollen gametes and for propagation of pure male sterile seeds. They will be used as female parents to be crossed with the elite male parents that have normal wild-type fertility and complementary agronomic performance to evaluate the heterosis of F1 plants.
