Park Soo-Young, Kim Rumi, Ryu Choong-Min, Choi Soo-Keun, Lee Choong-Hwan, Kim Jong-Guk, Park Seung-Hwan
Systems Microbiology Research Center, KRIBB, Daejeon, Korea.
FEMS Microbiol Ecol. 2008 Aug;65(2):229-37. doi: 10.1111/j.1574-6941.2008.00492.x. Epub 2008 May 1.
Paenibacillus polymyxa, a Gram-positive low-G+C spore-forming soil bacterium, belongs to the plant growth-promoting rhizobacteria. The swarming motility of P. polymyxa strain E681 was greatly induced by a secondary metabolite, citrinin, produced by Penicillium citrinum KCTC6549 in a dose-dependent manner at concentrations of 2.5-15.0 microg mL(-1) on tryptic soy agar plates containing 1.0% (w/v) agar. Flagellum staining showed that citrinin activated the production of flagella by P. polymyxa. This result was supported by reverse transcriptase-PCR analysis of gene expression, which showed increased transcriptional levels of sigD and hag homologues of P. polymyxa E681 in the presence of citrinin. The results presented here show that a mycotoxin, citrinin, has a newly identified function of inducing bacterial motility by transcriptional activation of related genes. This finding contributes to our understanding of the interactions between bacteria and fungal strains in nature.
多粘芽孢杆菌是一种革兰氏阳性、低G+C含量的产芽孢土壤细菌，属于促进植物生长的根际细菌。在含有1.0%（w/v）琼脂的胰蛋白胨大豆琼脂平板上，桔青霉KCTC6549产生的次生代谢产物桔霉素以2.5 - 15.0微克/毫升的浓度以剂量依赖的方式极大地诱导了多粘芽孢杆菌E681菌株的群体运动性。鞭毛染色显示桔霉素激活了多粘芽孢杆菌鞭毛的产生。基因表达的逆转录聚合酶链反应分析支持了这一结果，该分析表明在桔霉素存在的情况下，多粘芽孢杆菌E681的sigD和hag同源物的转录水平增加。此处呈现的结果表明，一种霉菌毒素桔霉素具有通过相关基因的转录激活来诱导细菌运动性的新确定功能。这一发现有助于我们理解自然界中细菌与真菌菌株之间的相互作用。
