Species Diversity, Mating Strategy and Pathogenicity of Species from Diseased Leaves and Soils in the Plantation in Southern China.

Many species are causal agents of diseases on several forestry, agricultural and horticultural crops. leaf blight is one of the most important diseases associated with plantations and nurseries in Asia and South America. Recently, symptoms of leaf rot and leaf blight caused by species were observed in a one-year-old experimental plantation in GuangXi Province, southern China. To better understand the species diversity, mating strategy and pathogenicity of species isolated from diseased tissues and soils, diseased leaves and soils under the trees from ten hybrid genotypes were collected. Three hundred and sixty-eight isolates were obtained from diseased leaves and soils under these trees, and 245 representative isolates were selected based on the sampling substrates and genotypes and identified by DNA sequence analyses based on the translation elongation factor 1-alpha (), β-tubulin (), calmodulin () and histone H3 () gene regions, as well as a combination of morphological characteristics. These isolates were identified as (50.2%), (47.4%), (1.6%), (0.4%) and (0.4%). This is the first report of and occurrence in China. was isolated from both diseased leaves and soils; the other four species were only obtained from soils. and gene amplification and mating type assignment results showed that is heterothallic and an asexual cycle represents the primary reproductive mode, and are likely to be heterothallic and and are homothallic. Based on the genetic diversity comparisons for isolates from diseased leaves and soils, we hypothesize that in soils was spread from diseased leaves. Both the mycelia plug and conidia suspension inoculations indicated that all five species were pathogenic to the two genotypes tested and the tolerance of the two genotypes differed. It is necessary to understand the ecological niche and epidemiological characteristics of these species and to select disease resistant genotypes in southern China in the future.