SL-IAA27 gene expression is induced during arbuscular mycorrhizal symbiosis in tomato and in Medicago truncatula

Abstract

Aux/IAA genes play a pivotal role in auxin transcriptional regulation. their functions were mainly studied in Arabidopsis through analysis of gain-of-function mutants. in the tomato, the Solanaceae reference species, different studies on Sl-IAA down-regulated lines showed specific role for Sl-IAA genes. our recent work revealed that the Sl-iaa27 gene displays a distinct behavior compared with most Aux/IAA genes, being down-regulated by auxin. interestingly, the silencing of Sl-IAA27 leads to altered chlorophyll accumulation in leaves, reduced fertilization, altered fruit development and altered root formation. here we report that IAA27 could be a key auxin signaling gene involved in am in tomato and also in Medicago model plant. indeed both Sl-IAA27 and its closest homolog in Medicago truncatula, Mt-IAA27, are overexpressed in mycorrhized roots. these data are in line with the putative role of auxin in arbuscular mycorrhization. © 2013 Landes Bioscience.