Transient expression of pepper Bs2 gene in Citrus limon as an approach to evaluate its utility for management of citrus canker disease

SENDIN, L.N.; FILIPPONE, M.P.; OCRE, I.G.; RIGANO, L.; ENRIQUE, R.; PEÑA, L.; VOJNOV, A.A.; MARANO, M.R.; CASTAGNARO, A.P.

PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2011 p. 1 - 10

0032-0862

The pepper Bs2 gene confers resistance to Xanthomonas campestris pv. vesicatoria (Xcv) pathogenic strains containing theavrBs2 avirulence gene in susceptible pepper and tomato. The avrBs2 gene is highly conserved in the Xanthomonas genusand when bacteria lack this gene their growth in a susceptible host is diminished, indicating that the avrBs2 gene productcould confer an adaptive advantage to the pathogen. The avrBs2 of Xanthomonas citri subsp. citri (Xcc), cause of citrus canker,shares 96% homology with avrBs2 of Xcv. To evaluate if Bs2 could recognize avrBs2 of Xcc in citrus plants andthereby activate plant defence mechanisms to increase resistance to canker, transient expression experiments were conductedusing Agrobacterium tumefaciens in lemon plants subsequently challenged with wildtype Xcc. The results showed that transientexpression of Bs2 reduced canker formation in lemon and induced plant defence mechanisms, as shown by callosedeposition and PR-1 expression. Moreover, when an avrBs2 mutant of Xcc was used, no decrease in disease symptoms wasobserved. This work shows that the Bs2 gene from Solanaceae is functional in lemon, a member of the Rutaceae family.Therefore, Bs2 is a potential candidate gene for stable expression in transgenic citrus plants in order to improve resistance tocanker disease.