Location: Crop Improvement and Protection ResearchTitle: Hormone signaling, growth, and defense response - Arabidopsis ndr1-1 takes center stage
|DHAR, NIKHILESH - University Of California|
|SHORT, DYLAN - University Of California|
|MAMO, BULLO - University Of California|
|CORRION, ALEX - Michigan State University|
|DAY, BRAD - Michigan State University|
|AJWA, HUSEIN - University Of California|
|McCreight, James - Jim|
|CASTEEL, CLARE - University Of California|
|SUBBARAO, KRISHNA - University Of California|
Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2019
Publication Date: 8/4/2019
Citation: Dhar, N., Short, D.P., Mamo, B.E., Anchieta, A.G., Corrion, A., Day, B., Ajwa, H., McCreight, J.D., Casteel, C., Subbarao, K.V., Klosterman, S.J. 2019. Hormone signaling, growth, and defense response - Arabidopsis ndr1-1 takes center stage. American Society of Plant Biologists Annual Meeting, August 4-7, 2019, San Jose, California.
Technical Abstract: Hormone signaling in plants is intricately involved in the cellular communication that coordinates growth, development, and defense responses. Diversion of resources supporting plant growth and development can occur during stress responses through hormonal imbalances and cross-talk. We analyzed the growth and development and defense-related hormone signaling in Arabidopsis thaliana mutants in response to the soil borne pathogen Verticillium spp. We discovered the interplay between defense and gibberellic acid (GA) hormone signaling that regulates growth and flowering time. Infection by two Verticillium species enhanced the early flowering phenotype of the Col-0 (WT) in a GA-dependent manner. Preliminary results indicate that Verticillium infection led to significant reduction in the levels of jasmonic Acid (JA) in the Col-0 (WT), while the levels of bioactive GA4 were significantly increased. These changes in GA levels were accompanied by shifts in expression levels of genes involved in the GA signaling pathway. We provide evidence that the widely characterized defense mutant ndr1-1 in A. thaliana displays early flowering and accelerated growth and significantly elevated GA levels compared with those of the wild type Col-0, and activates a branch of defense controlling CC-NBS-LRR genes (RPM1, RPS2 and RPS5) in a salicylic acid (SA)-dependent manner. In further support of this, ndr1-1 mutants have enhanced susceptibility and accelerated flowering in response to infection by another soil borne fungal pathogen, Fusarium oxysporum. NDR1 involvement in pathogen-mediated changes in flowering time and growth response represents an unexplored avenue for Salicylic Acid SA- GA cross-talk in plants upon activation of defense.