Poster: Plant-pathogen interactions

Abs # 571: Disease resistance and abiotic stress tolerance in rice is inversely regulated by an EIN2 homolog-mediated interplay between ethylene and abscisic acid signaling

Presenter:	Zhou, Xiangjun , xzhou@uark.edu
Authors	Zhou, Xiangjun  (A)   Yang, Yinong  (A)
Affiliations:	(A): Department of Plant Pathology, University of Arkansas

EIN2 is a central component of ethylene signaling pathway in Arabidopsis. In this study, we have isolated and sequenced the full-length cDNA of a rice EIN2 homolog. RNA blot analysis showed that the rice EIN2 homolog (OsEIN2) was constitutively expressed at a low level in various tissues and was not inducible by pathogen infection or chemical inducers. To determine the role of the OsEIN2 gene, the OsEIN2 suppression lines were generated through the RNA interference. Suppression of OsEIN2 did not change the ethylene level in the transgenic lines but negatively affected their seed germination, coleoptile elongation and flowering. Suppression of OsEIN2 also resulted in reduced sensitivity to ethylene, but hypersensitivity to abscisic acid. In comparison with control plants, the OsEIN2 suppression lines showed increased susceptibility to fungal (Magnaporthe grisea) and bacterial (Burkholderia glumae) infection and decreased induction of defense-related genes in the late stage of infection. Surprisingly, the same transgenic lines were much more tolerant to cold and salt treatments. These results strongly suggest that the rice EIN2 homolog mediates the cross-talk between ethylene and abscisic acid signaling and inversely regulates disease resistance and abiotic stress tolerance.