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Suberin consisting of the polyaliphatic and polyphenolic domain confers the hydrophobic barrier of wound fruit and vegetables, providing essential protection from excessive water loss, ion outflow and pathogen invasion. The ω-hydroxyacid/fatty alcohol hydroxycinnamoyl transferase (FHT) is required for cross-linking of the polyaliphatic and polyphenolic domain in suberin biosynthesis. The transcription factor AchMYC2 acts as a positive activator in suberin biosynthesis but it is not known how it interacts with AchFHT in kiwifruit. In this study, overexpression of AchFHT in kiwifruit increased accumulation of suberin monomers, such as ferulate and ω-hydroxyacids. Yeast one-hybrid (Y1H) and dual-luciferase reporter (DLR) assays showed that AchMYC2 activated AchFHT transcript via interacting with the gene promoter. Overexpression of AchMYC2 in kiwifruit resulted in the upregulation of AchFHT , the accumulation of FHT protein and suberin monomers. Further, using yeast two-hybrid (Y2H) assay screened a jasmonate ZIM-domain protein (AchJAZ1, a key repressor of JA signaling pathway) which interacted with AchMYC2. Methyl jasmonate (MeJA) treatment increased expression levels of AchMYC2 and AchFHT , and the content of FHT protein, accompanying by the rapid wound healing process, as indicated by rapid suberin deposition, the reduced weight loss and relative electrolyte leakage. These results indicate that AchMYC2 activates AchFHT transcript to involve in MeJA-mediated suberin biosynthesis in wound healing of kiwifruit. • Methyl jasmonate (MeJA) accelerated suberin deposition in wound healing of kiwifruit. • MeJA stimulated expression levels of AchFHT and AchMYC2 and increased FHT content. • AchMYC2 activated AchFHT transcript by interacting with the gene promoter. [ABSTRACT FROM AUTHOR]

Suberin polyaliphatics (SPA) is an important component of suberin, which plays a pivotal role in controlling water loss and solute fluxes during wound healing of fruit and vegetables. The objective of this study was to investigate the effect of exogenous methyl jasmonate (MeJA) on wound-induced SPA deposition in Chinese yam tubers. The results exhibited that MeJA treatment accelerated the deposition of SPA and the wound healing process. The gene expressions of β-ketoacyl-CoA synthases (DoKCS2 , DoKCS6), CYP86 subfamily of cytochrome P450 monooxygenases (DoCYP86A1 , DoCYP86B1) and Glycerol-3-phosphate acyltransferases (DoGPAT5 , DoGPAT7) and their corresponding protein content (i.e. KCS, CYP, GPAT) associated with SPA monomer biosynthesis were notably increased by MeJA application. Meanwhile, MeJA also enhanced gene expressions of ATP-binding cassette transporter subfamily G proteins (DoABCG2 , DoABCG6) and GDSL-type esterase/lipases (DoGELP38 , DoGELP51 , DoGELP96) and increased ABCG content, which might participate in the trafficking and polymerization of SPA monomer. Noteworthily, application of diethyldithiocarbamic acid (DICA), an inhibitor of jasmonic acid (JA) synthesis, showed an opposite effect to MeJA treatment. These results suggest that MeJA could promote SPA deposition by positively regulating relevant gene expression and corresponding protein content, thereby accelerating wound healing of Chinese yam tubers. • Methyl jasmonate (MeJA) could accelerate wound healing of yam tubers. • MeJA reduced weight loss and relative electrolyte leakage of wound yam tubers. • MeJA improved SPA deposition by increasing gene expressions and enzyme contents. [ABSTRACT FROM AUTHOR]

• AchLOX3 and AchOPR3 were involved in JA biosynthesis of kiwifruit. • ABA-induced AchABF1-1 was a nucleus-localized transcription factor. • AchABF1-1 activated AchLOX3 and AchOPR3 expression by binding to their promoters. • ABA promoted SPP formation by the induction of JA biosynthesis. Mechanical damage is a central limiting factor in the maintenance of the postharvest fruit quality during harvest, transportation, and processing. In this study, wounded kiwifruit (Actinidia chinensis cv. Xuxiang) were respectively treated with abscisic acid (ABA), fluridone (FLD, an inhibitor of ABA biosynthesis), methyl jasmonate (MeJA), diethyldithiocarbamic acid (DIECA, an inhibitor of JA biosynthesis), and ABA+DIECA to investigate the potential interaction between ABA and JA in the process of wound healing. The results showed that blocking JA biosynthesis significantly reduced the positive effect of ABA on the accumulation of suberin polyphenolic (SPP). Besides, transiently overexpressed the AchLOX3 and AchOPR3 in tobacco (Nicotiana benthamiana) leaves confirmed that these two genes respectively encoded lipoxygenase and 12-oxo-phytodienoic acid reductase involved in JA biosynthesis. Notably, the positive regulation of transcription factor (TF) AchABF1-1 on AchLOX3 and AchOPR3 was identified. ABA-induced AchABF-1 located in the nucleus and activated the transcriptional expression of AchLOX3 and AchOPR3 through binding to their promoters. These results were further confirmed in the tobacco leaves overexpressing AchABF1-1 in which AchABF1-1 promoted NbLOX and NbOPR expression with the increases of JA content. In addition, exogenous ABA increased endogenous JA content, and enhanced LOX and OPR activities as well as their related gene expression, while FLD reduced these indices. These results suggested that the promotion effect of JA on the SPP accumulation was enhanced through the promotion of JA biosynthesis by ABA-responsive transcription factor AchABF1-1 during the wound healing process of kiwifruit. [ABSTRACT FROM AUTHOR]

• AchnCYP86A1 and AchnFAR were involved in wound suberinzation of kiwifruit. • AcnMYB4 repressed AchnCYP86A1 and AchnFAR expression by binding to gene promoter. • ABA induced the AchnCYP86A1 and AchnFAR expression by inhibition of AchnMYB4. Suberin biosynthesis involves a large number of genes, and many of them are induced by abscisic acid (ABA). However, the regulation of transcription factor (TF) in response to ABA on suberin biosynthetic genes in kiwifruit has been unexplored. In this study, two genes, AchnCYP86A1 and AchnFAR respectively encoding a fatty acid ω-hydroxylase and fatty acyl-CoA reductase involved in suberin monomer biosynthesis were demonstrated in transient overexpressed tobacco (Nicotiana benthamiana). Notably, the negative regulation of AchnMYB4 on AchnCYP86A1 and AchnFAR was identified. AchnMYB4 could repress AchnCYP86A1 and AchnFAR transcript by directly binding to the gene promoter in yeast one-hybrid and dual-luciferase assays. These results were further confirmed in transient overexpressed tobacco leaves in that AchnMYB4 significantly down-regulated suberin biosynthetic genes including CYP86A1 , FAR2 and FAR3 , and reduced accumulation of ω-hydroxyacids and primary alcohols. Moreover, exogenous ABA could induce the expression of AchnCYP86A1 and AchnFAR , and the accumulation of corresponding suberin monomers by inhibition of AchnMYB4 in wound-tissue of kiwifruit. However, fluridone (an inhibitor of ABA biosynthesis) was found to counter the inductive effects of ABA. Taken together, the results suggest that ABA activates AchnCYP86A1 and AchnFAR to promote suberin monomers biosynthesis by inhibiting AchnMYB4. [ABSTRACT FROM AUTHOR]

Suberin polyphenolic (SPP), a kind of agronomically significant biopolymer, is composed primarily of phenolic acids generally synthesized by phenylpropanoid metabolism. In this study, the transcriptional activation of suberin polyphenolic biosynthesis by jasmonic acid (JA) inducible-transcription factor AchMYC2 was confirmed in wound tissues of kiwifruit (Actinidia chinensis). Three general phenylpropanoid metabolism-related genes, AchPAL , AchC4H and Ach4CL respectively encoding phenylalanine ammonia-lyase (PAL), cinnamic acid-4-hydroxylase (C4H) and 4-coumaric-CoA ligase were determined in the kiwifruit core tissues overexpressing these genes. Besides, the positive regulation of AchMYC2 on AchPAL , AchC4H and Ach4CL was observed. JA-induced AchMYC2 locating in the nucleus activated the transcriptional expression of AchPAL , AchC4H and Ach4CL through binding to their promoters. The results were further evidenced in the kiwifruit core tissues overexpressing of AchMYC2, in which AchMYC2 enhanced the expression levels of AchPAL , AchC4H and Ach4CL and increased the accumulation of phenolic acids including cinnamic acid, p -coumaric acid, caffeic acid, ferulic acid and sinapic acid. Meanwhile, the contents of five phenolic acids in the kiwifruit wound tissues were increased by methyl jasmonate (MeJA), but reduced by diethyldithiocarbamic acid (DIECA, an inhibitor of JA biosynthesis). Together results indicated that AchMYC2 activated AchPAL , AchC4H and Ach4CL transcription to promote JA-mediated suberin polyphenolic accumulation in the wound healing of kiwifruit. • AchPAL, AchC4H, and Ach4CL involved in suberin polyphenolic precursors synthesis. • MeJA-induced AchMYC2 was a nucleus-localized transcription factor. • AcnMYC2 activates AchPAL, AchC4H, and Ach4CL expression by binding to their promoters. • AchMYC2 promotes JA-mediated suberin polyphenolic accumulation of wounded kiwifruit. [ABSTRACT FROM AUTHOR]