Aamir Hamid Khan;Yizan Ma;Yuanlong Wu;Adnan Akbar;Muhammad Shaban;Abid Ullah;Jinwu Deng;Abdul Saboor Khan;Huabin Chi;Longfu Zhu;Xianlong Zhang;Min Lin

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, Hubei, China;Department of Botany, University of Malakand, Dir Lower 18800, Khyber Pakhtunkwa, Pakistan; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, Hubei, China;National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, Hubei, Chin

Cotton (Gossypium hirsutum);Jasmonic acid;Allene oxide cyclase 2;ROS;CRISPR/Cas9;High-temperature stres

Cotton (Gossypium spp.) yield is reduced by stress. In this study, high temperature (HT) suppressed the expression of the jasmonic acid (JA) biosynthesis gene allene oxide cyclase 2 (GhAOC2), reducing JA content and causing male sterility in the cotton HT-sensitive line H05. Anther sterility was reversed by exogenous application of methyl jasmonate (MeJA) to early buds. To elucidate the role of GhAOC2 in JA biosynthesis and identify its putative contribution to the anther response to HT, we created gene knockout cotton plants using the CRISPR/Cas9 system. Ghaoc2 mutant lines showed male-sterile flowers with reduced JA content in the anthers at the tetrad stage (TS), tapetum degradation stage (TDS), and anther dehiscence stage (ADS). Exogenous application of MeJA to early mutant buds (containing TS or TDS anthers) rescued the sterile pollen and indehiscent anther phenotypes, while ROS signals were reduced in ADS anthers. We propose that HT downregulates the expression of GhAOC2 in anthers, reducing JA biosynthesis and caus-ing excessive ROS accumulation in anthers, leading to male sterility. These findings suggest exogenous JA application as a strategy for increasing male fertility in cotton under HT.(c) 2022 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).