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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #431943
Research Project: Identifying Vulnerabilities in Vector-host-pathogen Interactions of Grapevine and Citrus Pathosystems to Advance Sustainable Management Strategies

Location: Crop Diseases, Pests and Genetics Research

Title: Grapevine CYP734A13 and CYP734A15 are both brassinosteroid-inactivating cytochrome P450 enzymes

Author
item Peng, Hao
item Zhai, Ying

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Grapevines (Vitis vinifera) are cultivated worldwide with fruits used for fresh consumption, wine brewing, juice, or raisin production. As a group of plant growth-promoting hormones, brassinosteroids (BRs) play extensive roles in multiple aspects of grapevine-environment interactions. BRs can enhance plant biomass accumulation, disease resistance, and tolerance to abiotic stress. Plant BR homeostasis can be modulated by a conserved cytochrome P450 family CYP734A that specifically inactivate BRs. However, grapevine CYP734As haven't been functionally characterized to date. Here, we cloned CYP734A13 and CYP734A15 from the popular table/raisin grape cultivar Thompson Seedless and demonstrated its BR-inactivating activity via ectopic expression in Arabidopsis thaliana. Overexpression of either CYP734A13 or CYP734A15 causes BR-deficient dwarfism in Arabidopsis, which can be rescued by exogenous application of brassinolide (BL), the most biologically active BR found in plants. The BR biosynthetic inhibitor brassinazole (BRZ) can abolish Arabidopsis seedling hypocotyl growth difference between CYP734A13/15 overexpression lines and mock plants harboring the empty vector. CYP734A13/15 overexpression also abolishes Arabidopsis seedling photomorphogenic phenotypes in high-fluence-rate white light conditions. Our findings collectively indicate that both CYP734A13 and CYP734A15 are valid brassinosteroid-inactivating P450 enzymes, which can be potential genome editing targets for elevating endogenous BR levels in grapevine.