Impact of UV irradiation in leaves, fruits and suspension-cultured cells of Micro-Tom, tomato

Abstract

The present study aims to understand both positive and negative impacts of ultraviolet (UV) rays in living dwarf tomato plants (Solanum lycopersicum L. cv. Micro-Tom). This paper examines the impact of UV-C (254 nm) and UV-A (365 nm) on induction of cell death and expression patterns of pathogenesis-related (PR), stress-related and redox-related genes, namely, of 1-amincocyclopropane-1-carboxylic acid synthase (ACS1a), cytosolic ascorbate peroxidise (APX), phenylalanine ammonia-lyase (PAL), and pathogenesis-related genes (PR1 and PR-P2), in leaves, fruits (both green and red), and suspension-cultured cells of Micro-Tom. Effects of short exposure to UV-C, but not to UV-A, on induction of cell death (in cell suspension) and development of lesions accompanied by ion leakage (in the leaves) were observed while no morphological change was observed in the UV-treated green and red fruits. UV-dependent induction of PR genes (PR1 and PR-P2) in these samples suggested that UVs can be used for plant defense activation. In addition, expression of ACS1a was shown to be negatively and positively regulated by UV-C and UV-A, respectively. Thus UV-dependent postharvest controls of fruit maturity and shelf-life are likely applicable (i.e. retardation and/or acceleration of maturation).