Poster: Plant-pathogen interactions

Abs # 543: Hypersenstive Response Induced by Compatible Bacterial pathogen in PFLP Transgenic Tobacco was harpin mediated

Presenter:	Huang, Hsiang En , hhn@gate.sinica.edu.tw
Authors	Huang, Hsiang En  (A)   Ger, Man-jey  (A)   Feng, Teung-yung  (A)
Affiliations:	(A): Academai Sinica,Institute of Botany

The hypersensitive response (HR) displayed by resistant plants against invading pathogens is a prominent feature of plant-pathogen interactions. It has been demonstrated that a plant ferredoxin-like protein (PFLP) from sweet pepper, that functions as an electron receptor of photosystem I, would affect the expression of harpinPss-mediated HR. In this work, overexpresion of PFLP in transgenic tobacco showed host resistance to virulent bacterial pathogens (Pseudomonas syringae pv. tabaci and Erwinia carotovora subsp. carotovora) infection. The leaves infected by compatible pathogens, E. carotovora subsp. carotovora and Pseudomonas syringae pv. tabaci exhibited several features: (i) a HR-like necrosis appeared and the proliferation of bacterial pathogens in tobacco leaves was highly retarded; (ii) the expression of a HR-marker gene, hsr203j, was apparently induced; (iii) the amounts of H2O2 and SA increased. These results postulate that the disease resistance of transgenic plants may result from the induction of a HR by a virulent pathogen infection. Indicated that PFLP might be an auxiliary protein for the elicitation of plant defense and the enhanced resistance to bacterial diseases could be achieved by increased expression of PFLP in transgenic tobacco. We also used harpin defective E. carotovora subsp. carotovora to further check the sensitivity of PFLP towards harpin. Interestingly, no HR was observed when PFLP transgenic were infected with harpin deficient E. carotovora subsp. carotovora. The above results suggested that disease resistance of pflp transgenic comes from the bacterial harpin.