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Virulence quenching with a prenylated isoflavanone renders the Malagasy legume Dalbergia pervillei resistant to Rhodococcus fascians
Author(s) -
Rajaonson Sanda,
Vandeputte Olivier M.,
Vereecke Danny,
Kiendrebeogo Martin,
Ralambofetra Eliane,
Stévigny Caroline,
Duez Pierre,
Rabemanantsoa Christian,
Mol Adeline,
Diallo Billo,
Baucher Marie,
El Jaziri Mondher
Publication year - 2011
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2011.02424.x
Subject(s) - biology , virulence , microbiology and biotechnology , leafy , botany , genetics , gene
Summary The phytopathogenic Actinomycete Rhodococcus fascians induces leafy galls on a wide range of hosts, causing major economical losses in the ornamentals industry. Although differences in the responsivity occur within species, no plant tested so far could be considered resistant to R. fascians strain D188 infection. Here, we observed that members of the genus Dalbergia , which belong to the Fabaceae, did not develop leafy galls when challenged with R. fascians and we set out to unravel the mechanism of this recalcitrance. Whereas organic extracts of Dalbergia tissues exhibited toxicity towards the bacteria, more importantly, dichloromethane bark extracts inhibited the induction of bacterial virulence gene expression without any apparent loss of viability, illustrating that resistance is likely multifactorial. The virulence quencher was identified as a new prenylated isoflavanone, termed perbergin, and specifically targeted the AttR regulon (a LysR‐type transcriptional regulator) which is imperative for the switch of R. fascians from an epiphytic to a pathogenic lifestyle. The mode of action of perbergin demonstrated that just like in Gram‐negative host–microbe interactions, also in Gram‐positive phytopathogens autoregulation is being targeted by the plant as an efficient means of defence. Moreover, the identification of perbergin opens the path to disease control in affected nurseries.