Abstract：Ralstonia solanacearum, the causal agent of bacterial wilt disease, demonstrates seriously pathogenic diversity. In order to understand the pathotypes of Ralstonia solanacearum strains from Fujian Province and its association to the composition of avirulence genes, the pathogenicity of 63 Ralstonia solanacearum strains isolated from different regions and host plants in the Fujian Province was detected using attenuation index (AI) method. The tested strains were divided into 3 pathogenic types which were virulent, interim and avirulent. The avirulence genes avrA, popP1 and popP2 of tested strains were also detected. Three avirulence genes had different distribution frequencies, avrA and popP1 showed the highest and lowest distribution frequency. It was 79.37% and 46.03%, respectively. The composition of avirulence genes of R. solanacearum strains differed in different host plants. The strains isolated from tomato (Lycopersicum esculentum) and pepper (Capsicum annuum) commonly contained 2~3 types of avirulence genes, but for the strains isolated from eggplant (Solanum melongena), two types of avirulence genes were the main distribution, and only avrA gene or no avirulence gene was detected in the strains isolated from peanut (Arachis hypogaea ). The composition of avirulence genes of R. solanacearum strains varied in different regions. Take R. solanacearum strains isolated from tomato host as an example, strains from Nanping City, Jianou County mainly distributed 3 and 2 types of avirulence genes, the proportion were 45.45% and 31.82%, respectively. Three avirulence genes were equally distributed in the strains from Ningde City, Pingnan County. Only avirulence genes avrA and popP2 were detected in the strains from Fuzhou City, Beifeng Town, and they were equally distributed. The strains from Fuzhou City, Yingkou Town had only popP2 gene, and the distribution frequency reached to 60.00%. Different pathogenic R. solanacearum strains had different composition of avirulence genes. For avirulent strains, 3 and 2 types of avirulence genes were the main distribution, while for interim strains 2 types of avirulence genes were detected, for virulent strains, only 1 type of avirulence gene was detected. Three avirulence genes showed positive correlation with the pathogenicity of R. solanacearum strains based on the Pearson correlation coefficient (PCC) analysis. The correlation coefficiency of popP1 gene to the pathogenicity of strains was the highest with the value of PCC 0.31, which reached to significantly positive. In conclusion, this work provides some important information for early warning and controlling the bacteria wilt disease.
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