Poster: Plant-pathogen interactions

Abs # 548: Using synthetic RPP1 gene clusters to model R-gene evolution by meiotic recombination

Presenter:	Sun, Jian , jisun3@vt.edu
Authors	Sun, Jian  (A)   Janakiraman, Vasant  (A)   McDowell, John  (A)   Jelesko, John  (A)
Affiliations:	(A): Fralin Biotechnology Center, Virginia Tech

Meiotic unequal crossing-over between paralogous gene within in a gene cluster causes gene rearrangements and the formation of novel chimeric genes with potential novel functions. Plants disease resistance genes (R genes) are frequently organized as gene clusters that encode proteins required for the recognition of invading pathogens and confer specific disease resistance to plants. In this study, we constructed a reconfigurable synthetic RPP1 gene cluster (synthRPP1) which is composed of three linked R gene homologs. The synthRPP1 gene cluster will be transformed into Arabidopsis CW84 which is susceptible to a wide variety of downy mildew isolates and transgenic plant lines that contain a single copy synthRPP1 will be selected. The initial synthRPP1 inserts will be alternatively reconfigured in vivo to produce two alternative RPP1 alleles. Lines containing the reconfigured synthRPP1 alleles will be crossed together to allow meiotic homologous recombination to form chimeric RPP1 genes. The chimeric RPP1 genes will be identified by a gain-of-Luciferase phenotype (luc+). Luc+ plants will be isolated and characterized for chimeric RPP1 gene structure and function. Future studies will include determining the frequency of several distinct types of meiotic recombination, mapping of recombination resolution sites, and determining altered or novel downey mildew recognition profiles. The poster will outline recent progress.