Homology-based identification of candidate genes for male sterility editing in Upland cotton (Gossypium hirsutum L.)

Authors: MORALES, KARINA - Texas A&M University; Bridgeland, Aya; KATER, HAKE - Cotton, Inc; Udall, Joshua - Josh; Yu, John; THOMPSON, MICHAEL - Texas A&M University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2022
Publication Date: 12/14/2022
Citation: Morales, K., Bridgeland, A.H., Kater, H., Udall, J.A., Yu, J., Thompson, M. 2022. Homology-based identification of candidate genes for male sterility editing in Upland cotton (Gossypium hirsutum L.). Frontiers in Plant Science. Article e2022.1006264. https://doi.org/10.3389/fpls.2022.1006264.
DOI: https://doi.org/10.3389/fpls.2022.1006264

Interpretive Summary: Many crop plants including Upland cotton exhibit hybrid vigor that is defined as the superior performance of a hybrid offspring over its inbred parents. To produce hybrid planting seeds, a female parent is prevented from self-pollination through either tedious emasculation or genetic male sterilization. The sources of genetic male sterility (GMS) in Upland cotton are limited with little knowledge of gene locations and/or protein products. These problems hinder the development and utilization of hybrid cotton in mechanized agriculture. In this study, we collected and analyzed genes related to male sterility in six plant species (Arabidopsis, maize, rice, soybean, tomato, and wheat). Through DNA and protein homology examination with these plant genes, we identified and characterized 20 candidate genes in the cotton genome. The biochemical modes, functional regulation, and evolutionary relationship of the candidate genes were analyzed, which would facilitate selection and construction of multiplex gene cassettes to simultaneously edit the genes for male sterility trait desirable in developing superior hybrid cotton.

Technical Abstract: Upland cotton (Gossypium hirsutum L.) accounts for more than 90% of the world’s cotton production, providing natural material for the textile and oilseed industries worldwide. One strategy for improving Upland cotton yields is through increased adoption of hybrids; however, emasculation of cotton flowers is incredibly time-consuming and genetic sources of cotton male sterility are limited. Here we review the known biochemical modes of plant nuclear male sterility (NMS), often known as plant genetic male sterility (GMS), and characterized them into four groups: transcriptional regulation, splicing, fatty acid transport and processing, and sugar transport and processing. In addition, we have explored protein sequence homology from GMS genes of three monocots (maize, rice, and wheat) and three dicots (Arabidopsis, soybean, and tomato) and have identified 20 potential candidate genes within the Upland cotton genome for the development of new male sterile germplasm to be used in hybrid cotton breeding. We have also analyzed evolutionary relationships between monocot and dicot GMS genes to describe the relative similarity and relatedness of these genes: of the genes identified, five were completely unique to their source species, four were unique to monocots, six unique to dicots, and 14 conserved among all species. Combining homology-based studies with genome editing may allow for the discovery and validation of GMS genes that previously had no diversity observed in cotton and may allow for development of a desirable male sterile mutant to be used in hybrid cotton production.