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Article|28 Feb 2023|OPEN
Novel flavin-containing monooxygenase protein FMO1 interacts with CAT2 to negatively regulate drought tolerance through ROS homeostasis and ABA signaling pathway in tomato
Lulu Wang1,2 ,† , Yinlian Zhou1,2 ,† , Yin Ding1,2 , Chunrui Chen1,2 and Xueting Chen1,2 , Nini Su1,2 , Xingguo Zhang1,2 , Yu Pan1,2 , Jinhua Li,1,2 ,
1State Cultivation Base of Crop Stress Biology for Southern Mountainous land of Southwest University, Academy of Agricultural Sciences, Southwest University, Beibei, Chongqing 400715, China
2Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400715, China
*Corresponding author. E-mail:
Both authors contributed equally to the study.

Horticulture Research 10,
Article number: uhad037 (2023)
Views: 393

Received: 13 Aug 2022
Accepted: 23 Feb 2023
Published online: 28 Feb 2023


Drought stress is the major abiotic factor that can seriously affect plant growth and crop production. The functions of flavin-containing monooxygenases (FMOs) are known in animals. They add molecular oxygen to lipophilic compounds or produce reactive oxygen species (ROS). However, little information on FMOs in plants is available. Here, we characterized a tomato drought-responsive gene that showed homology to FMO, and it was designated as FMO1FMO1 was downregulated promptly by drought and ABA treatments. Transgenic functional analysis indicated that RNAi suppression of the expression of FMO1 (FMO1-Ri) improved drought tolerance relative to wild-type (WT) plants, whereas overexpression of FMO1 (FMO1-OE) reduced drought tolerance. The FMO1-Ri plants exhibited lower ABA accumulation, higher levels of antioxidant enzyme activities, and less ROS generation compared with the WT and FMO1-OE plants under drought stress. RNA-seq transcriptional analysis revealed the differential expression levels of many drought-responsive genes that were co-expressed with FMO1, including PP2CsPYLsWRKY, and LEA. Using Y2H screening, we found that FMO1 physically interacted with catalase 2 (CAT2), which is an antioxidant enzyme and confers drought resistance. Our findings suggest that tomato FMO1 negatively regulates tomato drought tolerance in the ABA-dependent pathway and modulates ROS homeostasis by directly binding to SlCAT2.