Submitted to: Annual International Plant & Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2004
Publication Date: 1/14/2005
Citation: Albert, H.H., Qui, X., Buan, P., Wang, M.L., Moore, P.H., Ahu, Y.J., Hu, J., Borth, W.,. Establishment of cellular reducing conditions with sar induction in papaya, plant, animal & microbe genomes x11. abstract.. Annual International Plant & Animal Genome XIII Conference. Abstracts W265, P61. 2005. Interpretive Summary:
Technical Abstract: BTH induces elevated hydrolytic enzyme activity, expression of two members of the PR1 gene family, and resistance to Phytophthora palmivora in papaya. Twenty five additional papaya genes showing elevated systematic expression three days after BTH treatment have now been identified by suppression subtraction hybridization and confirmed and quantified by quantitative RT-PCR. These genes include several PR genes and related genes known from other systems to have direct anti-microbial activities, and two genes with likely involvement in altering cell wall porosity and lignification. Additionally, six genes with potential roles in establishing reducing conditions following the oxidative burst were induced, including three not previously known to have defense related roles: CPBI 6, a 2-oxoglutarae-dependant oxygenase (2OG-Fe(II) oxygenase), CPBI 14, a malate oxidoreductase, and CPBI 16, a hydroxyphenylpyuvate dioxygenase (HPPDase). In arabidosis, reducing conditions in the cell have been shown to convert cytoplasmic NPR1 oligomers to monomers which can enter the nucleus and activate certain TGA transcription factors. Together, these changes activate transcription of numerous PR genes which coincides with establishment of SAR. The formation of NPR1 oligomers is dependant on specific C residues and these C residues are conserved in the papaya NPR1 protein. Together these data indicate the establishment of cellular reducing conditions following the oxidative burst plays an important role in SAR induction papaya.