Upon bolting the GTR1 and GTR2 transporters mediate transport of glucosinolates to the inflorescence rather than roots

Abstract

We recently described the glucosinolate transporters GTR 1 and GTR 2 as actively contributing to the establishment of tissue-specific distribution of the defense compounds glucosinolates in vegetative Arabidopsis plants. Upon bolting and thereby development of the inflorescence and initiation of seed setting, the spatial distribution of glucosinolates does undergo major changes. Here we investigate the role of GTR 1 and GTR 2 in establishment of glucosinolate source-sink relationships in bolting plants. By in vivo feeding the exogenous p-hydroxybenzylglucosinolate to a rosette leaf or the roots of wildtype and a gtr1 gtr2 mutant, we show that this glucosinolate can specifically translocate from the rosette and the roots to the inflorescence in a GTR 1 - and GTR 2-dependent manner. This marks that, upon bolting, the inflorescence rather than the roots constitute the strongest sink for leaf glucosinolates compared with plants in vegetative state. © 2014 Landes Bioscience.