AUTHOR=Hu Wei , Kuang Fan , Lu Zhanjun , Zhang Ning , Chen Tingtao 

TITLE=Killing Effects of an Isolated Serratia marcescens KH-001 on Diaphorina citri via Lowering the Endosymbiont Numbers

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.00860

DOI=10.3389/fmicb.2018.00860

ISSN=1664-302X

ABSTRACT=<p>Huanglongbing (HLB) is the most devastating citrus disease worldwide, and suppression of the Asian citrus psyllid (<italic>Diaphorina citri</italic>) is regarded as an effective method to inhibit the spread of HLB. In this study, we isolated a strain named as <italic>Serratia marcescens</italic> KH-001 from <italic>D. citri</italic> nymphs suffering from disease, and evaluated its killing effect on <italic>D. citri</italic> via toxicity test and effect on microbial community in <italic>D. citri</italic> using high-throughput sequencing. Our results indicated that <italic>S. marcescens</italic> KH-001 could effectively kill 83% of <italic>D. citri</italic> nymphs, while the fermentation products of <italic>S. marcescens</italic> KH-001 only killed 40% of the <italic>D. citri</italic>nymphs. High-throughput sequencing results indicated that the <italic>S. marcescens</italic> KH-001 increased the OTU numbers from 62.5 (PBS buffer) to 81.5, while significantly lowered the Shannon index compared with <italic>Escherichia coli</italic> DH5α (group E) (<italic>p</italic> &lt; 0.05). OTU analysis showed that the <italic>S. marcescens</italic> KH-001 had significantly reduced the relative abundance of endosymbionts <italic>Wolbachia</italic>, <italic>Profftella</italic>, and <italic>Carsonella</italic> in group S compared with that in other groups (<italic>p</italic> &lt; 0.05). Therefore, the direct killing effect of the fermentation products of <italic>S. marcescens</italic> KH-001 and the indirect effect via reducing the numbers of endosymbionts (<italic>Wolbachia</italic>, <italic>Profftella</italic>, and <italic>Carsonella</italic>) of <italic>D. citri</italic> endow <italic>S. marcescens</italic> KH-001 a sound killing effect on <italic>D. citri</italic>. Further work need to do before this strain is used as a sound biological control agents.</p>