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Poster: Biology & Disease Mgmt: Genetics of Resistance


Transgenic expression of pattern recognition receptor EFR in tomato leads to effective field resistance to bacterial wilt
S. KUNWAR (1), S. Kunwar (1), E. Evaristo da Silva (2), F. Iriarte (2), L. Ritchie (2), D. Clark (2), J. Freeman (2), R. Stall (3), J. Jones (3), J. Minsavage (3), C. Zipfel (4), D. Horvath (5), M. Paret (2) (1) University of Florida, U.S.A.; (2) North Fl

Bacterial wilt of tomato caused by Ralstonia solancearum is a major problem in tomato production in the tropics and sub-tropics worldwide and can cause 50-80% yield losses. We investigated whether transgenic tomato (Solanum lycopersicum) expressing the resistance gene EFR (Elongation Factor Tu-Receptor) from Arabidopsis thaliana or Bs2 gene from Capsicum annuum or both provides improved resistance to bacterial wilt disease in a field with R. solanacearum. The presence of EFR and Bs2 or EFR alone on the highly susceptible FL 8000 background, significantly reduced the bacterial wilt incidence compared to Bs2 line (carrying only Bs2) or non-transformed control. Although yields of marketable fruit from EFR or EFR/Bs2 lines were statistically not different than those from Bs2 lines or non-transformed control, the total yield was significantly improved in the EFR and EFR/Bs2 lines. Following harvest, the basal and middle stem sections of the remaining living plants in the field were assessed by diluting plating on modified SMSA media. The results revealed no significant differences in the populations at the basal stem. Interestingly, in the middle stem, no bacteria could be recovered from EFR lines or EFR/Bs2 lines but R. solanacearum populations were recovered from Bs2 and non-transformed control lines at 104 CFU/g and 103 CFU/g tissue, respectively. This finding indicates the potential of EFR gene for field management of tomato bacterial wilt.