Diversity and antagonistic effect of endophytic bacteria isolated from Origanum vulgare L. in Xinjiang

Abstract:

[Background] Endophytes associated with plant have a wide range of applications in various fields, such as promoting plant growth, antagonistic activity, biological nitrogen fixation and degradation of toxic compounds. [Objective] The purpose of this study is to isolate and identify endophytic bacteria associated with Origanum vulgare L. and to evaluate their biological control ability against the apple canker disease in Xinjiang Wild Fruit Forest. [Methods] Culture-dependent method and 16S rRNA gene sequencing were used to identify the isolated strains. Endophytic bacteria were screened by plate confrontation method for their ability against the pathogen of apple canker. [Results] In this study, a collection of 168 endophytic bacteria were isolated from Origanum vulgare L. and identi?ed based on their 16S rRNA gene sequences as 4 phyla, 5 classes, 8 orders, 12 families and 17 genera. The dominant genus was Bacillus. Additionally, the results of isolation of endophytic bacteria from Origanum vulgare L. showed that TSA medium (M1) produced the highest diversity of bacteria, followed by NA medium (M6) and then Histidine-Raffinose medium (M5). The diversity of culturable endophytic bacteria from Origanum vulgare L. was rich in Xinyuan Wild Fruit Forest. The distribution of endophytic bacteria in root was more plentiful compared to that in stem and leaf. Fifty-nine strains of isolated endophytic bacteria were screened by plate confrontation method for their antagonistic against apple canker. The results demonstrate that a number of endophytic bacteria which can effectively inhibit the growth of pathogenic fungi of apple canker. [Conclusion] The diversity of endophytic bacteria associated with Origanum vulgare L. in Xinjiang was rich. In this study, a number of endophytic bacteria which can effectively inhibit the growth of pathogenic fungi of apple canker were screened out. Therefore, the results of this study provide a more abundant and effective source of endophytic bacteria from Origanum vulgare L. for biological control of apple canker disease in Xinjiang Wild Fruit Forest.

Key words:Origanum vulgare L., endophytic bacteria, diversity, apple canker, antagonism