Correlation between Ralstonia solanacearum population in soils and occurrence of tobacco bacterial wilt

To rapidly and accurately detect the population of Ralstonia solanacearum in tobacco-planting soils and to monitor the dynamic occurrence of tobacco bacterial wilt, a real-time fluorescent quantitative PCR (qRT-PCR) method was developed for real-timely monitoring the occurrence of R. solanacearum in tobacco-planting soils. The developed method was used to detect the overwintering population of R. solanacearum and the population of R. solanacearum when tobacco bacterial wilt occurred at Lincang and Wenshan tobacco-planting areas. The results showed that the specific primer (RSf1/RSr1) of endoglucanase gene from R. solanacearum had a high amplification efficiency and strong specificity, and there was a better linear relationship between C_T value of standard curve and the population of R. solanacearum in soils with the correlation coefficient of 0.996 5 and the amplification efficiency of 93.60%. The disease index of tobacco bacterial wilt negatively correlated to C_T value of R. solanacearum population in soils. The overwintering population of R. solanacearum and the population of R. solanacearum when tobacco bacterial wilt occurred were multiple detected by the developed method. This result indicated that the overwintering population of R. solanacearum positively correlated to final disease index. With the increase of overwintering population of R. solanacearum, the occurrence of tobacco bacterial wilt became more serious.