miR398b negatively regulates cotton immune responses to Verticillium dahliae via multiple targets

Authors: MIAO, YUHUAN - Huazhong Agricultural University; CHEN, KUN - Huazhong Agricultural University; DENG, JINWU - Huazhong Agricultural University; ZHANG, LIN - Huazhong Agricultural University; WANG, WEIRAN - Xinjiang Academy Of Agricultural And Reclamation Science; KONG, JIE - Xinjiang Academy Of Agricultural And Reclamation Science; Klosterman, Steven; ZHANG, XIANLONG - Huazhong Agricultural University; AIERXI, ALIFU - Xinjiang Academy Of Agricultural And Reclamation Science; ZHU, LONGFU - Huazhong Agricultural University

Submitted to: The Crop Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2021
Publication Date: 1/24/2022
Citation: Miao, Y., Chen, K., Deng, J., Zhang, L., Wang, W., Kong, J., Klosterman, S.J., Zhang, X., Aierxi, A., Zhu, L. 2022. miR398b negatively regulates cotton immune responses to Verticillium dahliae via multiple targets. The Crop Journal. 10(4):1026–1036. https://doi.org/10.1016/j.cj.2021.12.010.
DOI: https://doi.org/10.1016/j.cj.2021.12.010

Interpretive Summary: The varied roles of small ribonucleic acids or microRNAs (miRNAs) in influencing cellular processes are now being elucidated. Yet the roles of miRNAs in plants in response to Verticillium dahliae, a soilborne fungus that causes disease known as Verticillium wilt on over 400 plant species worldwide, have not yet been functionally examined. This study examines the role of a cotton miRNA known as miR398b following infection and colonization of cotton by Verticillium dahliae. Whether or not miR398b is expressed and how much is expressed influences the ability of cotton to defend itself against Verticillium dahliae. When miR398b is overexpressed in plants, there is increased Verticillium wilt disease when the plants are challenged with Verticillium dahliae. These findings provide additional insight on how plant defense responses can be regulated in response to the pathogen, and therefore provide potential avenues to exploit for increased disease resistance.

Technical Abstract: MicroRNAs (miRNAs) play essential roles in plant defense responses, although such roles have not been identified in cotton in response to the plant pathogenic fungus Verticillium dahliae. In this study, the functions of miR398b and its target genes in cotton-V. dahliae interaction were investigated. The transcript levels of miR398b were down-regulated by V. dahliae infection and miR398b overexpression in cotton made the plants more susceptible to V. dahliae. The results suggest that miR398b negatively regulates cotton resistance to V. dahliae. This may occur by miR398b repression of some CC-NBS-LRR genes via translational inhibition, interfering with defense responses and leading to cotton susceptibility to V. dahliae. Alternatively, miR398b may guide the cleavage of the mRNAs of GhCSD1, GhCSD2 and GhCCS, each of which functions in reactive oxygen species (ROS) regulation and homeostasis, thereby causing excessive ROS accumulation in miR398b-overexpressing plants in response to V. dahliae infection. This study suggests conserved and novel roles of miR398b in the cotton–V. dahliae interaction. These discoveries may be coupled with new strategies in cotton breeding programs to improve resistance to V. dahliae.