Botryosphaeria dothidea is a major postharvest causal agent of soft rot in kiwifruit. Methyl jasmonate (MeJA) is an important plant hormone that participates as a plant defense against pathogens from a signal molecule. However, the impact and regulatory mechanism of MeJA on the attenuation of kiwifruit fungal decay remains unknown. This work investigated the effects of exogenous MeJA on the enzyme activity, metabolite content and gene expression of the phenylpropanoid and jasmonate pathways in kiwifruit. The results revealed that MeJA inhibited the expansion of B. dothidea lesion diameter in kiwifruit (Actinidia chinensis cv. ‘Hongyang’), enhanced the activity of enzymes (phenylalanine ammonia lyase, cinnamate 4-hydroxylase, 4-coumarate: coenzyme A ligase, cinnamyl alcohol dehydrogenase, peroxidase and polyphenol oxidase), and upregulated the expression of related genes (AcPAL, AcC4H, Ac4CL, and AcCAD). The accumulation of metabolites (total phenolics, flavonoids, chlorogenic acid, caffeic acid and lignin) with inhibitory effects on pathogens was promoted. Moreover, MeJA enhanced the expression of AcLOX, AcAOS, AcAOC, AcOPR3, AcJAR1, AcCOI1 and AcMYC2 and reduced the expression of AcJAZ. These results suggest that MeJA could display a better performance in enhancing the resistance of disease in kiwifruit by regulating the phenylpropanoid pathway and jasmonate pathway.

Parthenocissus tricuspidata is a climbing plant of the grape family (Vitaceae) that grows on roadside stone banks and the walls of buildings (He et al. 2011). It is mainly used as an important orna...

Nanfeng tangerine (Citrus reticulata Blanco) is highly regarded for its nutritional and economic value. In January 2022, an unknown fruit rot was observed on Nanfeng tangerine fruits harvested from...

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Methyl jasmonate (MeJA) is a plant-signalling molecule that plays significant roles in stress reactions and defence responses. The goal of this study was to characterize the effects of exogenous MeJA application on the resistance of postharvest pear fruit to blue mould rot caused by Penicillium expansum and investigate the mechanism underlying the observed effects of MeJA application. MeJA treatment effectively reduced the lesion diameter of blue mould rot in pear fruit. Furthermore, MeJA significantly enhanced the activities of antioxidant and defence-related enzymes, such as polyphenol oxidase (PPO), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), β-1,3 glucanase (GLU) and chitinase (CHI); total phenol content also increased, and membrane lipid peroxidation decreased. MeJA treatment promoted the expression of PpPPO, Cu-ZnSOD, PpPOD, PpCAT, PpCHI and PpGLU. Overall, this experiment suggested that MeJA-induced pear fruit resistance against blue mould rot may be related to the enhanced activities of defence enzymes and gene expression.