Melatonin delays leaf senescence and enhances salt stress tolerance in rice

Abstract

Melatonin, an antioxidant in both animals and plants, has been reported to have beneficial effects on the aging process. It was also suggested to play a role in extending longevity and enhancing abiotic stress resistance in plant. In this study, we demonstrate that melatonin acts as a potent agent to delay leaf senescence and cell death in rice. Treatments with melatonin significantly reduced chlorophyll degradation, suppressed the transcripts of senescence-associated genes, delayed the leaf senescence, and enhanced salt stress tolerance. Genome-wide expression profiling by RNA sequencing reveals that melatonin is a potent free radical scavenger, and its exogenous application results in enhanced antioxidant protection. Leaf cell death in noe1, a mutant with over-produced H2O2, can be relieved by exogenous application of melatonin. These data demonstrate that melatonin delays the leaf senescence and cell death and also enhances abiotic stress tolerance via directly or indirectly counteracting the cellular accumulation of H2O2.

Melatonin Improves Waterlogging Tolerance of Malus baccata (Linn.) Borkh. Seedlings by Maintaining Aerobic Respiration, Photosynthesis and ROS Migration

“…Melatonin was reported to enhance plant tolerance against various abiotic stressors including cold, hot, drought, salinity, and chemical pollutants (Bajwa et al, 2014; Wei et al, 2014; Liang et al, 2015; Liu et al, 2015; Shi et al, 2015b; Li X. et al, 2016; Xu et al, 2016). But the effect of melatonin on waterlogging resistance is still to be investigated.…”

“…Also, melatonin as well as its metabolites can eliminate different kinds of ROS including superoxide anion $\left({\mathrm{O}}_2^{•-}\right)$, hydrogen peroxide (H 2 O 2 ), hydroxyl radical ( • OH), singlet oxygen ( 1 O 2 ), peroxynitrite anion (ONOO - ) and nitric oxide (NO) (Tan et al, 2013). Melatonin has been reported to protect plants against a variety of abiotic and biotic stresses (Zuo et al, 2014; Liang et al, 2015; Liu et al, 2015; Shi et al, 2015a; Wang et al, 2015; Zhao et al, 2015b; Li C. et al, 2016; Xu et al, 2016). The transgenic Arabidopsis plants, ecotopically expressing melatonin synthetic gene MzASMT1 , had higher endogenous melatonin production and significantly lower ROS than that of their wild types.…”

Melatonin Application to Pisum sativum L. Seeds Positively Influences the Function of the Photosynthetic Apparatus in Growing Seedlings during Paraquat-Induced Oxidative Stress

“…There are several reports on such melatonin application and its influence on protein and photosynthetic pigment degradation during aging (Wang et al, 2012, 2013a,b; Liang et al, 2015). However, there is little information concerning single application of melatonin to seeds and its effect on subsequent processes that occur in plants grown from these seeds.…”

“…The majority of previous studies ware focused on positive effect of melatonin in senescence process induced by different stress factors. Studies on salt-stressed rice discovered that melatonin treatment significantly reduced chlorophyll degradation, delayed leaf senescence, and enhanced salt stress tolerance (Liang et al, 2015). Melatonin suppressed expression of four senescence-associated genes involved in chlorophyll degradation [stay-green (SGR), non-yellow coloring 1 (NYC1) and 3 (NYC3) genes, and red chlorophyll catabolite reductase 1 (RCCR1)], as well as four senescence-induced genes (OsNAP, Osh36, Osh69, and OsI57), which are widely used as age-dependent or dark-induced leaf senescence markers in rice (Liang et al, 2015).…”

“…Studies on salt-stressed rice discovered that melatonin treatment significantly reduced chlorophyll degradation, delayed leaf senescence, and enhanced salt stress tolerance (Liang et al, 2015). Melatonin suppressed expression of four senescence-associated genes involved in chlorophyll degradation [stay-green (SGR), non-yellow coloring 1 (NYC1) and 3 (NYC3) genes, and red chlorophyll catabolite reductase 1 (RCCR1)], as well as four senescence-induced genes (OsNAP, Osh36, Osh69, and OsI57), which are widely used as age-dependent or dark-induced leaf senescence markers in rice (Liang et al, 2015). Soybean seed-coating with melatonin improved their tolerance to salt and drought stress, probably due to enhanced expression of genes related to photosynthesis, carbohydrate/fatty acid metabolism, and ascorbate biosynthesis (Wei et al, 2015).…”