Impacts of phytochrome loss-of-function mutations and overexpression on tomato fruit cuticle deposition

Abstract

The cuticle contributes in multiple ways to the adaptation of plants under different environmental conditions. In fleshy fruits, such as tomatoes (Solanum lycopersicum), the control of cuticle formation has a high relevance for both fruit physiology and agronomic/commercial aspects. Recently, studies carried out on A. thaliana plants and maize leaves have demonstrated a possible activation of genes involved in cuticle biosynthesis in response to phytochrome (PHY)-dependent light stimuli perception, with consequences for the cuticular wax biosynthesis and deposition in vegetative tissues. However, role of PHYs in controlling cuticle formation in fleshy fruits remains elusive. Therefore, this project aims to characterize the possible role played by PHYs (SlPHYA, SlPHYB1 e SlPHYB2) in controlling fruit cuticle biosynthesis and its consequences for the post-harvest fruit water loss. To this end, loss-of-function studies of monogenic phytochrome mutant and higher order mutants of various combinations combined with gain-of-function (PHY over-expressing lines) will be carried out. Red ripe fruits from all these genotypes will be compared regarding post-harvest water loss, superficial brightness and cuticle accumulation. By using these approaches, we expect to deepen our knowledge about the role of photoreceptors on fleshy fruit physiology and, in turn, facilitate identifying new biotechnological alternatives to minimize the economic losses caused by losses due to excessive postharvest water loss.(AU)