TY - JOUR
T1 - Defence Signalling Pathways Involved in Plant Resistance and Phosphite-Mediated Control of Phytophthora Cinnamomi
AU - Eshraghi, Leila
AU - Anderson, Jonathan P.
AU - Aryamanesh, Nader
AU - McComb, Jen A.
AU - Shearer, Bryan
AU - Giles, Giles E.
N1 - Funding Information:
Acknowledgments We thank Dr Philip O’Brien for his valuable input to this research. We also thank Mr. Gordon Thomson for his technical support on microscopic assessments. This work was funded by Murdoch University. The senior author was a recipient of an International Post-graduate Research Scholarship (IPRS) and a Murdoch University Research Scholarship (MURS).
PY - 2014/4
Y1 - 2014/4
N2 - Phytophthora cinnamomi is one of the most devastating plant pathogens worldwide. Current control of P. cinnamomi in natural ecosystems primarily relies on chemical phosphite (Phi). To investigate host- and Phi-mediated resistance, A. thaliana ecotypes and mutants defective in salicylic acid (SA), jasmonic acid (JA), ethylene (ET) and abscisic acid (ABA) signalling pathways were screened for susceptibility to P. cinnamomi. In contrast to Col-0, the aba2-4 mutant, deficient in the synthesis of ABA, was susceptible suggesting a role for ABA in resistance to P. cinnamomi. Phi treatment increased resistance in aba2-4, but not to the level of Col-0, suggesting that Phi may act through both ABA-dependent and ABA-independent pathways. Phi treatment or P. cinnamomi inoculation of Col-0 down-regulated AtMYC2, a positive regulator of ABA signalling, which negatively regulates JA/ET-related pathogenesis-related genes, such as PDF1.2, whilst positively regulating JA-mediated herbivore responses such as VSP and PI. Consistent with this, P. cinnamomi or Phi treatment caused up-regulation of PDF1.2 and THI2.1 and down-regulation of VSP2 and the ABA-responsive gene RD22. Despite the up-regulation of JA/ET-dependent defence genes, the JA-defective mutant, jar1-1 and ET-defective mutants, ein2-1 and etr1-3, showed wild-type levels of resistance to P. cinnamomi, suggesting that these JA/ET defences are not required for resistance to P. cinnamomi. These results suggest that the resistance response of Col-0 act, at least in part, through a mechanism dependent on ABA synthesis, which appears independent of the interaction between ABA and elements of the JA/ET pathway, whilst Phi-mediated resistance, although inducing a response resembling the resistance response of Col-0, is independent of ABA signalling.
AB - Phytophthora cinnamomi is one of the most devastating plant pathogens worldwide. Current control of P. cinnamomi in natural ecosystems primarily relies on chemical phosphite (Phi). To investigate host- and Phi-mediated resistance, A. thaliana ecotypes and mutants defective in salicylic acid (SA), jasmonic acid (JA), ethylene (ET) and abscisic acid (ABA) signalling pathways were screened for susceptibility to P. cinnamomi. In contrast to Col-0, the aba2-4 mutant, deficient in the synthesis of ABA, was susceptible suggesting a role for ABA in resistance to P. cinnamomi. Phi treatment increased resistance in aba2-4, but not to the level of Col-0, suggesting that Phi may act through both ABA-dependent and ABA-independent pathways. Phi treatment or P. cinnamomi inoculation of Col-0 down-regulated AtMYC2, a positive regulator of ABA signalling, which negatively regulates JA/ET-related pathogenesis-related genes, such as PDF1.2, whilst positively regulating JA-mediated herbivore responses such as VSP and PI. Consistent with this, P. cinnamomi or Phi treatment caused up-regulation of PDF1.2 and THI2.1 and down-regulation of VSP2 and the ABA-responsive gene RD22. Despite the up-regulation of JA/ET-dependent defence genes, the JA-defective mutant, jar1-1 and ET-defective mutants, ein2-1 and etr1-3, showed wild-type levels of resistance to P. cinnamomi, suggesting that these JA/ET defences are not required for resistance to P. cinnamomi. These results suggest that the resistance response of Col-0 act, at least in part, through a mechanism dependent on ABA synthesis, which appears independent of the interaction between ABA and elements of the JA/ET pathway, whilst Phi-mediated resistance, although inducing a response resembling the resistance response of Col-0, is independent of ABA signalling.
KW - Abiotic and biotic stress
KW - Abscisic acid
KW - Arabidopsis thaliana
KW - Oomycete pathogen
KW - Plant defence signalling
UR - http://www.scopus.com/inward/record.url?scp=84894245085&partnerID=8YFLogxK
U2 - 10.1007/s11105-013-0645-5
DO - 10.1007/s11105-013-0645-5
M3 - Article
AN - SCOPUS:84894245085
SN - 0735-9640
VL - 32
SP - 342
EP - 356
JO - Plant Molecular Biology Reporter
JF - Plant Molecular Biology Reporter
IS - 2
ER -