Novel flavin-containing monooxygenase protein FMO1 interacts with CAT2 to negatively regulate drought tolerance through ROS homeostasis and ABA signaling pathway in tomato

Abstract

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 FMO1. FMO1 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 PP2Cs, PYLs, WRKY, 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.

Hepatotoxicity assessment of innovative nutritional supplements based on olive-oil formulations enriched with natural antioxidants

“…FMO1, an enzyme pivotal in xenobiotic metabolism, showcased diminished expression levels ( 85 , 86 ). Furthermore, S100A8, functioning in the regulation of inflammatory processes as a calcium-binding protein, and HAO2 encoding a protein mainly involved in the oxidation of medium and long chain hydroxyacids, both exhibited notable reductions in expression ( 87 , 88 ). Lastly, THRSP, a gene regulating thyroid hormone responsiveness, displayed a significant decrease in expression ( 89 ).…”

NAC61 regulates late- and post-ripening osmotic, oxidative, and biotic stress responses in grapevine

“…We could then hypothesize that NAC61 is involved in ROS metabolism/homeostasis, on the one hand, by regulating the expression of genes involved in defense, while also activating mechanisms for ROS detoxification. Indeed, several genes involved in ROS scavenging/detoxification were found to be HCTs, such MIOX , a flavin-containing monooxygenase , AOX1A , an aldehyde dehydrogenase (ALDH288 ), a glutaredoxin , a GDH , and GST2 ( Zhang et al , 2012 ; Munir et al , 2020 ; Vanlerberghe et al , 2020 ; Wang et al , 2023 ).…”

Genome-Wide Identification of Catalase Gene Family and the Function of SmCAT4 in Eggplant Response to Salt Stress

“…The ROS scavenging system, comprising enzymatic and nonenzymatic components [36], is key to plant survival under adverse conditions. CATs, one of the most important ROS scavenging enzymes, has been involved in regulating plant response to abiotic stresses such as salt [37,38], drought [31,[39][40][41], cold [31], heat [42,43], osmotic stress [37], and biotic stresses including pathogenic microorganisms attack [30,[44][45][46][47][48][49][50], and insect invasion [51]. In addition, growth and development [27,52] and senescence [53] are also regulated by CATs in conjunction with growth-related hormones.…”