Wounding induces suberin deposition, relevant gene expressions and changes of endogenous phytohormones in Chinese yam (Dioscorea opposita) tubers

Abstract

Wounds on Chinese yam (Dioscorea opposita) tubers can ocurr during harvest and handling, and rapid suberisation of the wound is required to prevent pathogenic infection and desiccation. However, little is known about the causal relationship among suberin deposition, relevant gene expressions and endogenous phytohormones levels in response to wounding. In this study, the effect of wounding on phytohormones levels and the expression profiles of specific genes involved in wound-induced suberisation were determined. Wounding rapidly increased the expression levels of genes, including PAL, C4H, 4CL, POD, KCSs, FARs, CYP86A1, CYP86B1, GPATs, ABCGs and GELPs, which likely involved in the biosynthesis, transport and polymerisation of suberin monomers, ultimately leading to suberin deposition. Wounding induced phenolics biosynthesis and being polymerised into suberin poly(phenolics) (SPP) in advance of suberin poly(aliphatics) (SPA) accumulation. Specifically, rapid expression of genes (e.g. PAL, C4H, 4CL, POD) associated with the biosynthesis and polymerisation of phenolics, in consistent with SPP accumulation 3 days after wounding, followed by the massive accumulation of SPA and relevant gene expressions (e.g. KCSs, FARs, CYP86A1/B1, GPATs, ABCGs, GELPs). Additionally, wound-induced abscisic acid (ABA) and jasmonic acid (JA) consistently correlated with suberin deposition and relevant gene expressions indicating that they might play a central role in regulating wound suberisation in yam tubers.