Evidence of High Genetic Diversity and Differences in the Population Diversity of the Eucalyptus Leaf Blight Pathogen from Diseased Leaves and Soil in a Plantation in Guangxi, China.

is an important causal agent of leaf blight in southern China. This pathogen causes tree disease across numerous regions in southern China. In addition to diseased leaves, has occasionally been isolated from soil in plantations. The aim of this study was to clarify whether causing leaf blight in China is mainly clonally reproduced and to determine the potential spreading mechanism of between diseased leaves and soil. To this end, 10 polymorphic microsatellite markers were analyzed to detect the genetic diversity of 97 isolates from diseased leaves and soil in a plantation in Guangxi Zhuang Autonomous Region, southern China. The analysis showed that the genetic diversity of the isolates from both the diseased leaves and soil was high. However, the gene and genotype diversity of the isolates from diseased leaves were higher than those of the isolates from the soil. Moreover, all genotypes detected in the isolates from the soil were also found in the isolates from the diseased leaves. Structural analyses did not show clear population structures related to the population substrates of the diseased leaves or soil, and molecular variance analyses indicated that no significant genetic differentiation existed between the diseased leaf and soil populations. These results suggest that in soil spreads from diseased leaves, and that an asexual cycle is the primary reproductive mode in both diseased leaf and soil populations. This is the first study on the genetic diversity and population structure of . The high genetic diversity and spread pathways of this pathogen may pose challenges in controlling the disease. from both diseased leaves and soils in plantations needs to be carefully monitored for disease control and management.