Melatonin interaction with abscisic acid in the regulation of abiotic stress in Solanaceae family plants

Abstract

Solanaceous vegetable crops are cultivated and consumed worldwide. However, they often confront diverse abiotic stresses that significantly impair their growth, yield, and overall quality. This review delves into melatonin and abscisic acid (ABA) biosynthesis and their roles in abiotic stress responses. It closely examines the intricate interplay between melatonin and ABA in managing stress within plants, revealing both collaborative and antagonistic effects and elucidating the underlying molecular mechanisms. Melatonin and ABA mutually influence each other’s synthesis, metabolism and that of other plant hormones, a key focus of this study. The study highlights melatonin’s role in aiding stress management through ABA-dependent pathways and key genes in the melatonin-ABA interaction. Specifically, melatonin downregulates ABA synthesis genes and upregulates catabolism genes, leading to reduced ABA levels. It also directly scavenges H2O2, enhancing antioxidant enzyme activities, thereby underscoring their collaborative role in mediating stress responses. Moreover, the interplay between melatonin and ABA plays an essential role in multiple physiological processes of plants, including stomatal behaviors, wax accumulation, delay leaf senescence, seed germination, and seedlings growth, among others. Recognizing these relationships in Solanaceae vegetable crops holds great importance for improving agricultural practices and crop quality. In summary, this review offers a comprehensive overview of recent studies on the melatonin and ABA interplay, serving as a valuable resource for researchers and breeders dedicated to fortifying crop resilience and productivity within challenging environments.

Melatonin as a key regulator in seed germination under abiotic stress

“…Under abiotic stresses, reduced GAs biosynthesis results in reduced SG, 252 while MEL acts as positive regulator of GA biosynthesis 27 . MEL induced higher germination index and germination percentage were associated with higher GA production, higher expression of gene GAs biosynthesis genes (GA20ox and GA3ox), 240 and GID1 (a GA receptor), 253 and regulation of DELLA proteins in the GA signaling pathway 254 . Given these results, it can be inferred that MEL does regulate GA biosynthesis to regulate SG in plants under abiotic stress (Figure 5).…”

“…In this balance of ABA biosynthesis and ABA catabolism, MEL plays a relevant role in determining the fate of seeds by regulating ABA metabolism and signaling (Figure 5). MEL application downregulates the expression of ABA biosynthesis gene ( NECD2) , while upregulates the expression of ABA catabolism ( CYP707A1 and CsCYP707A2) , thus governs SG and seedling growth 188,240,241 . MEL application lowered ABA contents and increased number of pores with large guard cells in seed coat to facilitate seed imbibition and improve SG under DS 242 .…”

“…MEL application downregulates the expression of ABA biosynthesis gene (NECD2), while upregulates the expression of ABA catabolism (CYP707A1 and CsCYP707A2), thus governs SG and seedling growth. 188,240,241 MEL application lowered ABA contents and increased number of pores with large guard cells in seed coat to facilitate seed imbibition and improve SG under DS. 242 The expression levels of ABA catabolism genes (CYP707A1-A4) in dry seeds of the AtPMRT1 mutant were significantly higher than that of the WT, while Arabidopsis seeds overexpressing-PMTR1 showed lower expression than in the WT, thus indicating PMTR1 may play a role in regulating ABA catabolism during SG in Arabidopsis thaliana.…”

Have All of the Phytohormonal Properties of Melatonin Been Verified?

“…Interestingly, melatonin increases the concentration of itself [ 65 ]. All of melatonin’s effects concerning abiotic stress [ 5 , 6 , 66 , 67 , 68 , 69 , 70 ], biotic stress [ 6 , 7 , 8 , 71 , 72 ], and growth and development [ 5 , 66 , 69 , 70 ] have been extensively reviewed in recent years.…”

“…The increased ABA is reduced through degradation and conjugation [ 77 ]. In contrast to the cooperative effect of melatonin and ABA on plant responses to environmental stress, melatonin contributes to the maintenance of hormonal balance in Malus plants by decreasing the expression of the NECD gene encoding 9-cis-epoxycarotenoid dioxygenase, which is involved in ABA biosynthesis, or by promoting the expression of enzymes that catabolize ABA [ 68 , 78 ]. Melatonin also affects GA biosynthesis.…”