CSB Seminar Series – Kee Hoon Sohn, PhD – Department of Agricultural Biotechnology, Seoul National University

CSB Departmental Seminar

Kee Hoon Sohn, PhD

Department of Agricultural Biotechnology, Seoul National University

TITLE: An atypical NLR confers bacterial wilt resistance in a wild Solanum species

ABSTRACT: Ralstonia solanacearum is a devastating pathogen that causes bacterial wilt disease in many plant hosts and causes severe yield loss in the field. However, only a few numbers of resistance genes were identified to induce immunity against R. solanacearum. Solanum americanum is a close relative of economically important solanaceous crops, and it is diploid with a 1.1Gb genome and harbors around 500 nucleotide-binding leucine-rich repeat receptors (NLRs), which makes S. americanum desirable for finding novel resistance genes. To identify novel bacterial wilt resistance genes, natural accessions of Solanum americanum were tested for bacterial wilt resistance. R. solanacearum type III-secreted effector RipAZ1 from Pe_26 strain was previously shown to trigger immune responses in S. americanum SP2273 accession but not in SP2275. Using bulk segregant analysis, we mapped the resistance gene locus at the upper arm of chromosome 5. Among 19 candidate NLRs, Resistance to R. solanacearum 1a (Rrs-amr1a) and Rrs-amr1b are shown to be required as pair NLRs for RipAZ1 recognition. Interestingly, Rrs-amr1a has an atypical NLR architecture with an additional nucleotide-binding leucine-rich repeat domain in its C-terminal. Taken together, identifying the novel pair NLRs that recognize RipAZ1 will help develop bacterial wilt-resistant solanaceous crops. Future studies on the function of integrated domains of Rrs-amr1a and how the pair NLRs triggers immunity will elucidate the mechanism of bacterial wilt resistance in S. americanum.

HOST: Darrell Desveaux

LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432