TY - JOUR
T1 - The bacterial alarmone (p)ppGpp is required for virulence and controls cell size and survival of Pseudomonas syringae on plants
AU - Chatnaparat, Tiyakhon
AU - Li, Zhong
AU - Korban, Schuyler S.
AU - Zhao, Youfu
N1 - Publisher Copyright:
© 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - The stringent response, mediated by second messenger (p)ppGpp, results in swift and massive transcriptional reprogramming under nutrient limited conditions. In this study, the role of (p)ppGpp on virulence of Pseudomonas syringae pv. syringaeB728a (PssB728a) was investigated. The virulence of the relA/spoT (ppGpp0) double mutant was completely impaired on bean, and bacterial growth was significantly reduced, suggesting that (p)ppGpp is required for full virulence of P.syringae. Expression of T3SS and other virulence genes was reduced in ppGpp0 mutants. In addition, ppGpp deficiency resulted in loss of swarming motility, reduction of pyoverdine production, increased sensitivity to oxidative stress and antibiotic tolerance, as well as reduced ability to utilize γ-amino butyric acid. Increased levels of ppGpp resulted in reduced cell size of PssB728a when grown in a minimal medium and on plant surfaces, while most ppGpp0 mutant cells were not viable on plant surfaces 24h after spray inoculation, suggesting that ppGpp-mediated stringent response temporarily limits cell growth, and might control cell survival on plants by limiting their growth. These results demonstrated that ppGpp-mediated stringent response plays a central role in P.syringae virulence and survival and indicated that ppGpp serves as a global signal for regulating various virulence traits in PssB728a.
AB - The stringent response, mediated by second messenger (p)ppGpp, results in swift and massive transcriptional reprogramming under nutrient limited conditions. In this study, the role of (p)ppGpp on virulence of Pseudomonas syringae pv. syringaeB728a (PssB728a) was investigated. The virulence of the relA/spoT (ppGpp0) double mutant was completely impaired on bean, and bacterial growth was significantly reduced, suggesting that (p)ppGpp is required for full virulence of P.syringae. Expression of T3SS and other virulence genes was reduced in ppGpp0 mutants. In addition, ppGpp deficiency resulted in loss of swarming motility, reduction of pyoverdine production, increased sensitivity to oxidative stress and antibiotic tolerance, as well as reduced ability to utilize γ-amino butyric acid. Increased levels of ppGpp resulted in reduced cell size of PssB728a when grown in a minimal medium and on plant surfaces, while most ppGpp0 mutant cells were not viable on plant surfaces 24h after spray inoculation, suggesting that ppGpp-mediated stringent response temporarily limits cell growth, and might control cell survival on plants by limiting their growth. These results demonstrated that ppGpp-mediated stringent response plays a central role in P.syringae virulence and survival and indicated that ppGpp serves as a global signal for regulating various virulence traits in PssB728a.
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U2 - 10.1111/1462-2920.12744
DO - 10.1111/1462-2920.12744
M3 - Article
C2 - 25626964
AN - SCOPUS:84949315639
SN - 1462-2912
VL - 17
SP - 4253
EP - 4270
JO - Environmental Microbiology
JF - Environmental Microbiology
IS - 11
ER -