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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #415112
Research Project: Disease Management and Improved Detection Systems for Control of Pathogens of Vegetables and Strawberries

Location: Crop Improvement and Protection Research

Title: Verticillium dahliae secretory aspartyl protease VdSAP targets cotton GhARP to modulate plant defence and defoliation

Author
item LI, HAIYUAN - Northwest A&f University
item GAI, XIAOTONG - Yunnan Academy Of Agriculture Sciences
item XU, XIANGMING - National Institute Of Agricultural Botany (NIAB)
item QIN, JUN - Northwest A&f University
item Klosterman, Steven
item SUBBARAO, KRISHNA - University Of California
item SHANG, WENJING - Northwest A&f University
item HU, XIAOPING - Northwest A&f University

Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2025
Publication Date: 4/19/2025
Citation: Li, H., Gai, X., Xu, X., Qin, J., Klosterman, S.J., Subbarao, K.V., Shang, W., Hu, X. 2025. Verticillium dahliae secretory aspartyl protease VdSAP targets cotton GhARP to modulate plant defence and defoliation. Molecular Plant Pathology. 26(4). Article e70085. https://doi.org/10.1111/mpp.70085.
DOI: https://doi.org/10.1111/mpp.70085

Interpretive Summary: The soilborne fungus Verticillium dahliae is the cause of vascular wilt disease on numerous plant species worldwide. The fungus penetrates the plant through roots, and invades the water conducting xylem tissue of the plant to cause wilt. Some strains of the fungus cause defoliation of plants like cotton. This research characterizes a secreted protein from a defoliating strain of V. dahliae that regulates cellular processes and plant hormones that lead to defoliation and increased virulence. The research provides valuable insights on the molecular mechanisms that regulate virulence of the fungus which are useful in developing disease control measures. The knowledge is also useful to further differentiate defoliating versus nondefoliating strains of the fungus.

Technical Abstract: Verticillium dahliae isolates causing devastating vascular wilt in cotton plants can be divided into defoliating and nondefoliatingpathotypes. The mechanisms underlying how V. dahliae uses secretory proteins to manipulate plant physiological processesand suppress immunity in cotton plants have received renewed research focus over the past several years. Here, we describe therole of a secretory protein named VdSAP (secretory aspartyl protease) from the defoliating V. dahliae strain XJ592 in virulenceand defoliation. Deletion of VdSAP in strain XJ592 led to significantly reduced virulence and cotton plant defoliation. VdSAPfunctioned as a protease that targeted cotton plant GhARP (auxin-repressed protein), and VdSAP negatively regulated GhARPcontent in plants. Transient expression of GhARP in Nicotiana benthamiana enhanced the expression of plant defence signalsand inhibited plant abscission signals. Furthermore, GhARP negatively regulated the ethylene (ET) signal and positively regu-lated the salicylic acid (SA) signal. In addition, GhARP interacted with 1-aminocyclopropane carboxylate oxidases (GhACOs),suggesting that it might function through the ET signal during V. dahliae–cotton plant interactions. These results suggest thatGhARP is a molecular link between plant defence and abscission signals, and that VdSAP decreases accumulation of GhARPand enhances the virulence and defoliation caused by V. dahliae.