TY - JOUR
T1 - Identification of Indole-3-Acetic Acid-Regulated Genes in Pseudomonas syringae pv. tomato Strain DC3000
AU - Djami-Tchatchou, Arnaud Thierry
AU - Li, Zipeng Alex
AU - Stodghill, Paul
AU - Filiatrault, Melanie J.
AU - Kunkel, Barbara N.
N1 - Funding Information:
This work was supported by National Science Foundation grant IOS-1645908 (to B.N.K. and M.J.F.) and USDA-ARS project 8062-21000-042-00-D (to M.J.F. and P.S.). Z.A.L. was a WUSTL BioSURF fellow.
Publisher Copyright:
Copyright © 2022 American Society for Microbiology. All Rights Reserved.
PY - 2022/1
Y1 - 2022/1
N2 - The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000). To learn more about the impact of IAA on regulation of PtoDC3000 gene expression, we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by quantitative reverse transcription PCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta. Collectively the data indicate that IAA modulates many aspects of PtoDC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain PtoDC000 and one of its hosts, Arabidopsis thaliana. However, the mechanisms by which IAA impacts the biology of PtoDC3000 and promotes disease are not well understood. Here, we demonstrate that IAA is a signal molecule that regulates gene expression in PtoDC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in type III secretion and genes involved in stress response. This work offers insight into the roles of auxin-promoting pathogenesis.
AB - The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000). To learn more about the impact of IAA on regulation of PtoDC3000 gene expression, we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by quantitative reverse transcription PCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta. Collectively the data indicate that IAA modulates many aspects of PtoDC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain PtoDC000 and one of its hosts, Arabidopsis thaliana. However, the mechanisms by which IAA impacts the biology of PtoDC3000 and promotes disease are not well understood. Here, we demonstrate that IAA is a signal molecule that regulates gene expression in PtoDC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in type III secretion and genes involved in stress response. This work offers insight into the roles of auxin-promoting pathogenesis.
KW - Arabidopsis
KW - Auxin
KW - Gene expression
KW - Indole-3-acetic acid
KW - Pathogenesis
KW - Plant pathogen
KW - Type III secretion
KW - Virulence
UR - http://www.scopus.com/inward/record.url?scp=85123425475&partnerID=8YFLogxK
U2 - 10.1128/JB.00380-21
DO - 10.1128/JB.00380-21
M3 - Article
C2 - 34662236
AN - SCOPUS:85123425475
SN - 0021-9193
VL - 204
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 1
M1 - e00380-21
ER -