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Visualizing the relevance of bacterial blue‐ and red‐light receptors during plant–pathogen interaction
Author(s) -
Ricci Ada,
Dramis Lucia,
Shah Rashmi,
Gärtner Wolfgang,
Losi Aba
Publication year - 2015
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12320
Subject(s) - pseudomonas syringae , virulence , mutant , biology , pathogen , blue light , host (biology) , arabidopsis thaliana , microbiology and biotechnology , arabidopsis , phototropism , gene , bacteria , wild type , phytochrome , genetics , botany , red light , physics , optics
Summary The foliar pathogen P seudomonas syringae pv. tomato DC 3000 ( P st ) leads to consistent losses in tomato crops, urging to multiply investigations on the physiological bases for its infectiveness. As other P . syringae pathovars, P st is equipped with photoreceptors for blue and red light, mimicking the photosensing ability of host plants. In this work we have investigated P st strains lacking the genes for a blue‐light sensing protein ( Pst LOV ), for a bacteriophytochrome ( P st B ph1) or for heme‐oxygenase‐1. When grown in culturing medium, all deletion mutants presented a larger growth than wild‐type ( WT ) P st under all other light conditions, with the exception of blue light which, under our experimental conditions (photon fluence rate = 40 μmol m −2 s −1 ), completely suppressed the growth of the deletion mutants. Each of the knockout mutants shows stronger virulence towards A rabidopsis thaliana than Pst WT , as evidenced by macroscopic damages in the host tissues of infected leaves. Mutated bacteria were also identified in districts distant from the infection site using scanning electron microscopy. These results underscore the importance of P st photoreceptors in responding to environmental light inputs and the partial protective role that they exert towards host plants during infection, diminishing virulence and invasiveness.