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Title: GLOBAL EXPRESSION PROFILING OF PATHOGEN-DEFENSE RELATED GENES FROM PAPAYA

Author
item QUI, XIAOHUI - HI AG RES CNT
item WANG, MING-LI - HI AG RES
item ZHU, Y - HI AG RES CNT
item Moore, Paul
item Albert, Henrik

Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2003
Publication Date: 7/25/2003
Citation: Qui, X., Wang, M., Zhu, Y.J., Moore, P.H., Albert, H.H. 2003. Global expression profiling of pathogen-defense related genes from papaya. American Society of Plant Physiologists. Abstract P792. p.168. 2003.

Interpretive Summary: Abstract only.

Technical Abstract: Papaya has been shown to respond to pathogen challenge and benzothiadiazole (BTH) treatment with an increase in ß-glucanase and chitinase enzyme activities [1]. To allow global analysis of defense related gene regulation, we have isolated a set of papaya genes which are up-regulated in response to BTH treatment. This set of genes was obtained in a subtracted cDNA library using suppression subtractive hybridization [2, 3]. 28 unique EST sequences were obtained from 34 clones randomly selected from this library and 14 of them were confirmed by northern blot to be induced by BTH. 332 additional clones were screened by reverse northern analysis and confirmed by northern blot. Quantitative analysis of mRNA levels was performed on a phosphoimager system. In all 26 unique ESTs upregulated by BTH (> 1.5 fold induction) have been isolated from the subtracted cDNA library. Among these are ESTs for a peroxidase, two chitinases and one osmotin-like protein which may be used as molecular markers of systemic acquired resistance in papaya. After root inoculation with Phytophthora palmivora, a virulent pathogen of papaya, the peroxidase mRNA level in leaves was found to be increased significantly six days after inoculation; however PR1A , the two chitinases and the osmotin-like protein mRNA were not detectably changed. In future work, these SAR marker genes may be used to compare plant responses to avirulent vs. virulent pathogens, or to analyze plant protection treatments. 1. Zhu, Y.J., et al. Acta Horticulturae, 2002. 576: p. 475-481. 2. Diatchenko, L., et al. Methods Enzymol, 1999. 303: p. 349-80. 3. Diatchenko, L., et al. Proc Natl Acad Sci U S A, 1996. 93(12): p. 6025-30.