INVESTIGADORES
CASTAGNARO Atilio Pedro
artículos
Título:
Inducible expression of Bs2 R gene from Capsicum chacoense in sweet orange (Citrus sinensis L. Osbeck) confers enhanced resistance to citrus canker disease
Autor/es:
SENDÍN , L; ORCE, GI; GÓMEZ, R; GRELLET BOURNONVILLE, CF; NOGUERA, AS; VOJNOV, AA; MARANO, MR; CASTAGNARO, AP; FILIPPONE, MP
Revista:
PLANT MOLECULAR BIOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2017 vol. 93 p. 607 - 621
ISSN:
0167-4412
Resumen:
Pepper Bs2 gene confers resistance to Xanthomonas campestris pv. vesicatoria (Xcv) pathogenic strains containing the avrBs2 avirulence gene in susceptible pepper and tomato varieties. The avrBs2 gene is highly conserved among members of the Xanthomonas genus, and the avrBs2 of Xcv shares 96% homology with the avrBs2 of Xanthomonas citri subsp. citri (Xcc), the causal agent of citrus canker disease. A previous study showed that transient expression of pepper Bs2 in lemon leaves reduced canker formation and induced plant defence mechanisms. In this work, the effect of stable expression of Bs2 gene on citrus canker resistance was evaluated in transgenic plants of Citrus sinensis cv. Pineapple. Interestingly, Agrobacterium-mediated transformation of epicotyls was unsuccessful when a constitutive promoter (35SCaMV) was used in the plasmid construction, but seven transgenic lines were obtained with a genetic construction harbouring Bs2 under the control of a pathogen-inducible promoter, the glutathione S-transferase gene from potato. Reduction of disease symptoms of up to 70% was observed in transgenic lines expressing Bs2 with respect to non-transformed control plants. This reduction was directly depending dependent on the Xcc avrBs2 gene since no effect was observed when a mutant strain of Xcc with a disruption in avrBs2 gene was inoculatedused for inoculations. Additionally, canker symptoms reduction was correlated with levels of Bs2 expression in transgenic plants, as assessed by real-time qPCR, and accompanied by production of reactive oxygen species. These results indicate that pepper Bs2 resistance gene is also functional in families other different than family to the Solanaceae, and could be considered for canker control.Pepper Bs2 gene confers resistance to Xanthomonas campestris pv. vesicatoria (Xcv) pathogenic strains containing the avrBs2 avirulence gene in susceptible pepper and tomato varieties. The avrBs2 gene is highly conserved among members of the Xanthomonas genus, and the avrBs2 of Xcv shares 96% homology with the avrBs2 of Xanthomonas citri subsp. citri (Xcc), the causal agent of citrus canker disease. A previous study showed that transient expression of pepper Bs2 in lemon leaves reduced canker formation and induced plant defence mechanisms. In this work, the effect of stable expression of Bs2 gene on citrus canker resistance was evaluated in transgenic plants of Citrus sinensis cv. Pineapple. Interestingly, Agrobacterium-mediated transformation of epicotyls was unsuccessful when a constitutive promoter (35SCaMV) was used in the plasmid construction, but seven transgenic lines were obtained with a genetic construction harbouring Bs2 under the control of a pathogen-inducible promoter, the glutathione S-transferase gene from potato. Reduction of disease symptoms of up to 70% was observed in transgenic lines expressing Bs2 with respect to non-transformed control plants. This reduction was directly depending dependent on the Xcc avrBs2 gene since no effect was observed when a mutant strain of Xcc with a disruption in avrBs2 gene was inoculatedused for inoculations. Additionally, canker symptoms reduction was correlated with levels of Bs2 expression in transgenic plants, as assessed by real-time qPCR, and accompanied by production of reactive oxygen species. These results indicate that pepper Bs2 resistance gene is also functional in other different than family to the Solanaceae, and could be considered for canker control.Agrobacterium-mediated transformation; AvrBs2 gene; Citrus breeding; Glutathione S-transferase promoter; Resistance genes; Xanthomonas citri subsp. citri