Seasonal variation and detection frequency of Candidatus Liberibacter asiaticus in Binchuan, Yunnan province China

In this study, we investigated the seasonal variations in the population dynamics of Clas and assessed the possible genetic variations among the identified isolates. We conducted a disease survey in tangerine citrus groves affected with HLB in Binchuan county, Yunnan province, China, on a monthly basis over a period of one year. The collected leaf samples were analyzed every month via nested PCR, targeting the 16S rRNA and the β-operon ribosomal protein-encoding genes of Clas. The abundance of the HLB-causing pathogen changes several times, with high temperatures in July 2017 yielding low pathogen abundance, followed by a high peak in December and January 2017-18. The number of bacteria inside each tree was inconsistent, showing drastic variations every month. Clas-negatively affected the endophytic microbial communities inside the citrus trees. There could be a direct relationship between the low number of endophytes and the high number of pathogens present inside each tree. Moreover, the genetic diversity of Clas can be used to elucidate the pattern and epidemiology of this pathogen in different regions. The obtained sequences were phylogenetically related to other sequences from China. A comparison of Clas gene sequences revealed little variation among the isolates circulating in China. The primers used in this study did not show cross-reactivity with other plant pathogens or with endophytes isolated from citrus trees. In addition, no mismatches were observed when an in s...
Source: Physiological and Molecular Plant Pathology - Category: Molecular Biology Source Type: research