Poster: Plant Pathogen/Symbiont Interactions

Abs # 690: The Sweet Pepper Ferredoxin-like Protein (pflp) Conferred Resistance against Soft Rot Disease in Oncidium Orchid

Presenter:	Chan, Ming-Tsair , mbmtchan@gate.sinica.edu.tw
Authors	Chan, Ming-Tsair  (A)   Liau, Chia-Hui  (A)   Lu, Jian-Cheng  (A)   Prasad, Venkatesh  (A)   Hsiao, Hsin-hao  (A)   You, Su-Juan  (A)   Lee, Jent-turn  (A)   Yang, Ning-Sun  (A)   Huamg, Hsiang-En  (B) (C)  Feng, Teng-Yung  (B)   Chen, Wen-Huei  (D)
Affiliations:	(A): Institute of BioAgricultural Sciences, Academia Sinica (B): Institute of Botany, Academia Sinica (C): Institute of Plant Pathology, National Taiwan University (D): Taiwan Sugar Corporation
Web Site:	http://www.sinica.edu.tw/~mbmtchan

Genetic engineering till date has not been used to introduce disease resistant genes in the orchid gene pool. The ferredoxin-like protein gene originally isolated from sweet pepper is thought to function as a natural defense against infection due to its antimicrobial properties. Hence it was reasoned that introduction of this gene might confer Oncidium resistant against Erwinia carotovora, the causal agent for the soft rot disease. An expression vector containing sweet pepper ferredoxin-like protein (pflp) cDNA, hph and gusA coding sequence was successfully transformed into protocorm-like bodies (PLBs) of Oncidium orchid by Agrobacterium tumefaciens strain EHA105. A total of 17 independent transgenic orchid lines were obtained, out of which 6 transgenic lines (GUS positive) were randomly selected and confirmed by Southern, northern and western blot analyses. A bioassay was conducted on the transgenic lines. The transgenic plants showed enhanced resistance to Erwinia carotovora, even when the entire plant was challenged with the pathogen. Our results suggest that the pflp gene may be an extremely useful gene for genetic engineering strategies in orchids to confer resistance against soft rot disease.