Melatonin mediates reactive oxygen species homeostasis via SlCV to regulate leaf senescence in tomato plants

Abstract

Melatonin (MT) functions in removing reactive oxygen species (ROS) and delaying plant senescence, thereby acting as an antioxidant; however, the molecular mechanism underlying the specific action of MT is unclear. Herein, we used the mutant plants carrying the MT decomposition gene melatonin 3‐hydroxylase (M3H) in tomato to elucidate the specific mechanism of action of MT. SlM3H‐OE accelerated senescence by decreasing the content of endogenous MT in plants. SlM3H is a senescence‐related gene that positively regulates aging. MT inhibited the expression of the senescence‐related gene SlCV to scavenge ROS, induced stable chloroplast structure, and delayed leaf senescence. Simultaneously, MT weakened the interaction between SlCV and SlPsbO/SlCAT3, reduced ROS production in photosystem II, and promoted ROS elimination. In conclusion, MT regulates ROS homeostasis and delays leaf aging in tomato plants through SlCV expression modulation.

Melatonin-mediated development and abiotic stress tolerance in plants

“…(2018) confirmed that melatonin synthesis enzymes ( MeTDC2 and MeASMT2/3 ) interact with MeWRKY20/75 to form a protein complex that extends the complex signaling of melatonin modulation. Not only ROS reduction in PSII but also circadian rhythm fluctuations have been mediated in melatonin-treated tomato, according to the weakened interaction between Sl CV and Sl PsbO /Sl CAT3 /Sl M3H ( Yu et al., 2022 ). In addition, a set of miRNAs (such as miR8029-3p, miR159-5p, miR858, and novel-m0048-3p) is able to negatively regulate target mRNAs in response to melatonin-mediated cold resistance ( Li et al., 2016 ).…”

Genetic and evolutionary dissection of melatonin response signaling facilitates the regulation of plant growth and stress responses

“…305 M3H overexpression in transgenic rice increased the number of secondary tiller and panicles that are pivotal agronomic traits governing grain yield, while the accelerated leaf senescence was observed in M3H overexpressing tomato. 309,310 Arabidopsis M3H knockout mutant exhibited retarded growth with rosette leaves and delayed flowering. 306 Phylogenetic analysis is important for evaluating functional conservation and diversification of gene family (Figure 8B).…”

“…307 M3H from Solanaceae were clustered into clades A and B implying functional differentiation in plant reproductive growth. 310 The close relationship of M3H from cotton, grape, and soybean with that from Arabidopsis suggested their conservation function in seedling growth and flowering. 306 M3H in cereal plant had an important role in grain yield.…”

“…22 ). 310 M2H and M3H mainly mediated phytohormone and expression of related genes to regulate plant growth. M3H exhibited a close correlation with tiller-associated genes, such as MOC1 and TB1 to regulate the number of secondary tillers in rice.…”

“…M3H gene expressed abundantly in rice shoots and roots implying its important role in seedling growth 305 . M3H overexpression in transgenic rice increased the number of secondary tiller and panicles that are pivotal agronomic traits governing grain yield, while the accelerated leaf senescence was observed in M3H overexpressing tomato 309,310 . Arabidopsis M3H knockout mutant exhibited retarded growth with rosette leaves and delayed flowering 306 .…”