AUTHOR=Xu Zhizhou , Wang Mingyuan , Du Jinpeng , Huang Ting , Liu Jianfu , Dong Tao , Chen Yinglong 

TITLE=Isolation of Burkholderia sp. HQB-1, A Promising Biocontrol Bacteria to Protect Banana Against Fusarium Wilt Through Phenazine-1-Carboxylic Acid Secretion

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.605152

DOI=10.3389/fmicb.2020.605152

ISSN=1664-302X

ABSTRACT=<p>Fusarium wilt is a devastating soil-borne fungal disease caused by <italic>Fusarium oxysporum</italic> f.sp. <italic>cubense</italic> (Foc). In recent years, some antifungal bacteria have been applied for the prevention and biocontrol of pathogenic fungi. In our study, a bacterial strain HQB-1, isolated from banana rhizosphere soil, was cultured for investigation. It showed broad-spectrum antifungal activities against representative phytopathogenic fungi including <italic>Fusarium oxysporum</italic>, <italic>Colletotrichum gloeosporioides</italic>, <italic>Botrytis cinerea</italic>, and <italic>Curvularia fallax</italic>. The strain HQB-1 was identified as <italic>Burkholderia</italic> sp. by morphological, physiological, and biochemical examinations, confirmed by 16S rRNA gene sequence analysis. Among the metabolites produced by the strain, we identified an antifungal compound which was identified phenazine-1-carboxylic acid (PCA) (C<sub>13</sub>H<sub>8</sub>N<sub>2</sub>O<sub>2</sub>) through ultraviolet, liquid chromatography quadrupole-time of flight mass spectrometer, and nuclear magnetic response. Furthermore, PCA exhibited the lowest minimum inhibitory concentration (MIC) against <italic>F. oxysporum</italic> (1.56 μg/ml) and yielded the highest MIC against <italic>C. gloeosporioides</italic>. Pot experiments showed that application of 5 μg/ml or more of PCA efficiently controlled banana wilt and promoted the growth of banana plants. These results suggested that <italic>Burkholderia</italic> sp. HQB-1, as an important microbial resource of PCA, could be a promising biological agent against wilt diseases and promoting banana growth.</p>