Romão A S, Spósito M B, Andreote F D, Azevedo J L, Araújo W L
Departamento de Genética, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Piracicaba, SP, Brasil.
Genet Mol Res. 2011 Feb 15;10(1):243-52. doi: 10.4238/vol10-1gmr952.
The endophyte Guignardia mangiferae is closely related to G. citricarpa, the causal agent of citrus black spot; for many years these species had been confused with each other. The development of molecular analytical methods has allowed differentiation of the pathogen G. citricarpa from the endophyte G. mangiferae, but the physiological traits associated with pathogenicity were not described. We examined genetic and enzymatic characteristics of Guignardia spp strains; G. citricarpa produces significantly greater amounts of amylases, endoglucanases and pectinases, compared to G. mangiferae, suggesting that these enzymes could be key in the development of citrus black spot. Principal component analysis revealed pectinase production as the main enzymatic characteristic that distinguishes these Guignardia species. We quantified the activities of pectin lyase, pectin methylesterase and endopolygalacturonase; G. citricarpa and G. mangiferae were found to have significantly different pectin lyase and endopolygalacturonase activities. The pathogen G. citricarpa is more effective in pectin degradation. We concluded that there are significant physiological differences between the species G. citricarpa and G. mangiferae that could be associated with differences in pathogenicity for citrus plants.
内生真菌芒果球座菌与柑橘黑斑病的病原菌柑橘球座菌密切相关；多年来，这两个物种一直相互混淆。分子分析方法的发展使得能够将病原菌柑橘球座菌与内生真菌芒果球座菌区分开来，但尚未描述与致病性相关的生理特征。我们研究了球座菌属菌株的遗传和酶学特性；与芒果球座菌相比，柑橘球座菌产生的淀粉酶、内切葡聚糖酶和果胶酶数量显著更多，这表明这些酶可能是柑橘黑斑病发展的关键因素。主成分分析表明，果胶酶的产生是区分这些球座菌属物种的主要酶学特征。我们对果胶裂解酶、果胶甲酯酶和内切多聚半乳糖醛酸酶的活性进行了定量；发现柑橘球座菌和芒果球座菌的果胶裂解酶和内切多聚半乳糖醛酸酶活性存在显著差异。病原菌柑橘球座菌在果胶降解方面更有效。我们得出结论，柑橘球座菌和芒果球座菌之间存在显著的生理差异，这可能与对柑橘植物致病性的差异有关。
