Deficient Cu availability alters hormone profiling during tomato fruit ripening

Abstract

Copper (Cu) is an essential microelement with low bioavailability in croplands, which severely affects plant growth, yield and quality. The aim of this work was to decipher whether Cu deficiency (CuD) during cultivation changes the levels of salicylic (SA), indole-3-acetic (IAA), and abscisic (ABA) acids, and different jasmonic acid (JA)-related metabolites, throughout tomato (S. lycopersicum L. cv. Moneymaker) fruit ripening; and whether these changes differ between whole fruit and the pericarp. Overall, basal levels of hormones were greater in whole fruit than in the pericarp, mostly at the mature green (MG) fruit stage. CuD triggered a rise in JA precursor cis-(+)-12-oxo-phytodienoic acid (OPDA) and a decrease in IAA and JA in the whole fruit at the MG stage, while no significant effects on either JA-derivatives methyl jasmonate (MeJA) and jasmonoyl-isoleucine (JAIle), or ABA and SA contents, was found. However, in the red ripe (RR) stage, CuD did not alter JA but increased JAIle and decreased OPDA and MeJA contents. Major differences between whole fruit and pericarp in response to CuD occurred in RR fruit, which showed an increased cracking incidence and susceptibility to postharvest Botrytis cinerea infection when exposed to the stress. These dissimilarities consisted on an increase in IAA, a reduction in SA, and the avoidance of JAIle increase in the pericarp. This study highlights, for the first time, that preharvest CuD influences hormone accumulation and favors tomato fruit quality loss, and that the effect of stress on hormones differs between whole fruit and pericarp in a maturation-dependent way.