Abstract

Leaf blight of Camellia oleifera is one of the major diseases in Camellia producing areas of China. The pathogen infects leaves of the host plants and causes leaves to drop, resulting in early defoliation and new treetops death and eventually yield reduction. The pathogen of leaf blight was isolated from the infected leaves ofC. oleifera (NO.CSUFT070160B). The internal transcribed spacer (ITS) region of the nuclear ribosomal DNA from pathogen was sequenced and comprises 516 bp. By comparing them with the sequences in the Gene Bank, we found that the strain was highest homologous to Pestalotiopsis microspora; and the concordance ratio is 99%. The molecule phylogenetic tree indicated that the CSUFT070160B and DQ000995 were in the same branch with high confidence level. Combined with morphological characteristics, the strain was checked as P. microspora. For the control of the C. oleifera leaf blight, antagonistic bacteria were screened from 175endophytic bacteria by confront culture method. The results showed that the antagonistic effect of YB18 strain was the best with 84.7% inhibitory rate. According to the results of the morphology, cultural characteristics, physiological and biochemical properties, 16S gene sequence and molecular phylogenetic tree, YB18 was identified as the strain belonging to Bacillus subtilis.

Key words: Camellia oleifera, leaf blight, pathogen, antagonistic bacteria, biological control.