Abstract

Many carrots are discarded during post harvest cold storage due to development of fungal infections, caused by,e.g.,Mycocentrospora acerina (liquorice rot). We compared the susceptibility of carrots grown under conventional and organic agricultural practices. In one year, organically cultivated carrots showed 3× to 7× more symptoms than conventionally cultivated, when studying naturally occurring disease at 4 and 6months, respectively. On the other hand, we have developed a bioassay for infection studies ofM. acerinaon carrots and observed that organic roots were more susceptible after one month of storage than conventional ones, but no differences were apparent after four or six months storage. Levels of polyacetylenes (falcarinol, falcarindiol and falcarindiol-3-acetate) did not change, whereas the isocoumarin phytoalexin (6-methoxymellein) accumulated in infected tissue as well as in healthy tissue opposite the infection. The proteomes of carrot and M. acerina were characterized, the intensity of 33 plant protein spots was significantly changed in infected roots including up regulation of defence and stress response proteins but also a decrease of proteins involved in energy metabolism. This combined metabolic and proteomic study indicates that roots respond to fungal infection through altered metabolism: simultaneous induction of 6-methoxymellein and synthesis of defence related proteins.

Keywords

carrot proteome. Mycocentrospora acerina; organic production polyacetylenes; 6-Methoxymellein

Published in

Journal of Proteomics
2012, volume: 75, number: 3, pages: 962-977
Publisher: Elsevier B.V

Authors' information