SlMYC2 Involved in Methyl Jasmonate-Induced Tomato Fruit Chilling Tolerance.

MYC2, a basic helix-loop-helix transcription factor, is a master regulator in Jasmonic acid (JA) signaling pathway. However, the functions of SlMYC2 in methyl jasmonate (MeJA)-mediated fruit chilling tolerance are far from being clearly understood. Thus, in the present work, we constructed SlMYC2-silenced tomato fruit by virus-induced gene silencing (VIGS) and investigated the function of SlMYC2 in MeJA-induced tomato fruit chilling tolerance. The results showed that MeJA treatment markedly induced the SlMYC2 expression; increased proline content, lycopene content, and antioxidant enzyme activities, including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase; inhibited the increase of electrical conductivity and malondialdehyde content; and effectively reduced the chilling injury (CI) incidence and CI index. However, these effects of MeJA treatment were partially counteracted in SlMYC2-silenced tomato fruit, and the CI incidence and CI index in ( SlMYC2-silenced + MeJA)-treated fruit were higher than those in MeJA-treated fruit. Our results indicated that SlMYC2 might be involved in MeJA-induced chilling tolerance, possibly by ameliorating the antioxidant enzyme system of fruit and increasing proline and lycopene levels.

Effect of methyl salicylate in combination with 1-methylcyclopropene on postharvest quality and decay caused by Botrytis cinerea in tomato fruit.

BACKGROUND: Postharvest diseases result in major losses in fruits. Tomato is susceptible to postharvest rot caused by Botrytis cinerea and is regarded as a good model system to study postharvest disease and quality deterioration in fruit. To develop a safe and effective technique to alleviate disease and maintain fruit quality, the effects of methyl salicylate (MeSA) and 1-methylcyclopropene (1-MCP) either separately or combined on quality and gray mold caused by B. cinerea in tomato fruit were investigated. RESULTS: The results showed that application of MeSA (0.05 mmol L-1 ) delayed fruit ripening and reduced gray mold. Compared with MeSA treatment, 1-MCP (0.5 µL L-1 ) effectively delayed fruit ripening. Further, MeSA combined with 1-MCP treatment was more effective in inhibiting fungal decay during storage than MeSA treatment alone. The combined treatment not only enhanced pathogenesis-related protein 1 (PR1) expression, activities of defense enzymes and total phenolic content but also inhibited the increase in electrical conductivity and malondialdehyde content. The combined treatment was also more effective in retaining firmness, color change and titratable acidity content than MeSA treatment alone. CONCLUSION: MeSA combined with 1-MCP treatment was a useful technique to maintain quality and alleviate gray mold in postharvest tomato fruit during storage. © 2018 Society of Chemical Industry.