Endophytic bacterial community in Gannan navel orange affected by huanglongbing

Abstract:

[Objective] To analyze the endophytic bacteria in leaves of Huanglong disease affected and healthy Gannan navel oranges, and to compare the bacterial community under different culture conditions. [Methods] Candidatus Liberibacter was verified by PCR. Based on 16S rRNA gene high throughput sequencing, the diversity of endophytic bacteria in the leaves of diseased and healthy plants (each five plants) cultured in different media was analyzed. [Results] Thirteen strains existed in diseased plants and seven of them were also found in all healthy plants. The dominant bacterial population of both diseased and healthy plants was mainly from Defluviicoccus sp. and Granulicella sp., whose average contents in healthy plants were higher than that in diseased ones. The similarity of diseased and healthy samples had obvious boundary. The strains obtained after cultivation in different samples and media were different. Enterobacter sp., Curtobacterium sp., Pseudomonas sp. and Pantoea sp. got a lot of enrichment, whereas the enrichment of 9 genera including Acinetobacter sp. and Serratia sp. was less. Besides, the amount of unclassified bacteria in the samples had obvious differences. [Conclusion] There were obvious differences between endophytic bacteria in disease and healthy Gannan navel oranges. The existence of Ca. Liberibacter changed the bacterial community structures. Only direct detection from the living plant tissue could obtain the real endophytic bacterial distribution. It is expected to find the bacteria associated with Ca. Liberibacter growth by analyzing the community difference of bacteria.