Lignin Biosynthesis in Postharvest Water Bamboo () Shoots during Cold Storage Is Regulated by -Mediated Reactive Oxygen Species Signaling.

Lignification is a major cause of senescence in fresh shoots of water bamboo (), which is a popular vegetable in southeast Asia; however, its physiological and molecular mechanisms is less understood. In the present study, lignin content and transcriptome change in postharvested water bamboo shoots under cold storage were investigated. We found that lignin significantly accumulated in the epidermis of the shoots with the increase of firmness. In the cold storage shoots, the major up-regulated genes were involved in phenylpropanoid biosynthesis, plant-pathogen interactions, and starch and sucrose metabolism. The lignin biosynthesis genes , , , , , , , and family were up-regulated during cold storage, while and were down-regulated. The MAPK signaling pathway was also up-regulated and () genes were strongly up-regulated. Therefore, we investigated the gene family and their expression profile in water bamboo shoots. The results indicated that 10 were up-regulated in cold storage shoots. Diphenyleneiodonium chloride (DPI), an inhibitor of RBOH oxidase, significantly inhibited the expression of genes involved in lignin deposition and biosynthesis, while HO enhanced these processes. These results suggest that lignification of water bamboo shoots is regulated by -mediated ROS signaling.