Back to overview

Arabidopsis YELLOW STRIPE-LIKE7 (YSL7) and YSL8 Transporters Mediate Uptake of Pseudomonas Virulence Factor Syringolin A into Plant Cells

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Publication date 2013
Author Hofstetter Silvia Schelbert, Dudnik Alexey, Widmer Heidi, Dudler Robert,
Project Structure, function and biosynthesis of syrbactins
Show all

Original article (peer-reviewed)

Volume (Issue) 26(11)
Page(s) 1302 - 1311
DOI 10.1094/MPMI-06-13-0163-R


Syringolin A (SylA), a virulence factor secreted by certain strains of the plant pathogen Pseudomonas syringae pv. syringae (Pss), is an irreversible proteasome inhibitor imported by plant cells by an unknown transport process. Here we report that functional expression in yeast of all 17 members of the Arabidopsis oligopeptide transporter family revealed that OLIGOPEPTIDE TRANSPORTER1 (OPT1), OPT2, YELLOW STRIPE-LIKE3 (YSL3), YSL7, and YSL8 rendered yeast cells sensitive to growth inhibition by SylA to different degrees, strongly indicating that these proteins mediated SylA uptake into yeast cells. Greatest SylA sensitivity was conferred by YSL7 and YSL8 expression. An Arabidopsis ysl7 mutant exhibited strongly reduced SylA-sensitivity in a root growth inhibition assay, and in leaves of ysl7 and ysl8 mutants, SylA-mediated quenching of salicylic acid (SA)-triggered PATOGENESIS-RELATED GENE1 (PR-1) transcript accumulation was greatly reduced as compared to the wild type. These results suggest that YSL7 and YSL8 are major SylA uptake transporters in Arabidopsis. Expression of a YSL homolog of bean, the host of the SylA-producing Pss strain B728a, in yeast also conferred strong SylA sensitivity. Thus, YSL transporters, which are thought to be involved in metal homeostasis, have been hijacked by bacterial pathogens for SylA uptake into host cells.