In Bacillus subtilis, motility genes are expressed in a hierarchical pattern – governed by the σ^D transcription factor and other proteins such as the EpsE molecular clutch and SlrA/SlrR regulator proteins. In contrast, motile species in the Bacillus cereus group seem to express their motility genes in a non-hierarchical pattern, and less is known about their regulation, also given that no orthologs to σ^D, EpsE, SlrA or SlrR are found in B. cereus group genomes. Here we show that deletion of cdgL (BTB_RS26690/BTB_c54300) in Bacillus thuringiensis 407 (cry-) resulted in a six-to ten-fold downregulation of the entire motility locus, and loss of flagellar structures and swimming motility. cdgL is unique to the B. cereus group and is found in all phylogenetic clusters in the population except for group I, which comprises isolates of non-motile Bacillus pseudomycoides. Analysis of RNA-Seq data revealed cdgL to be expressed in a three-gene operon with a NupC like nucleoside transporter, and a putative glycosyl transferase for which transposon-based gene inactivation was previously shown to produce a similar phenotype to cdgL deletion. Interestingly, all three proteins were predicted to be membrane-bound and may provide a concerted function in the regulation of B. cereus group motility.

在枯草芽孢杆菌中，运动基因以分层模式表达 - 由 σ ^D转录因子和其他蛋白质（如 EpsE 分子离合器和 SlrA/SlrR 调节蛋白）控制。与此相反，在该能动物种蜡状芽孢杆菌群似乎表达在非分层图案其蠕动基因，而较少有人知道它们的调节，还因为没有向直系同源物σ ^d，EPSE，SLRA或SLRR中发现B.蜡状组基因组。在这里，我们表明，删除cdgL（BTB_RS26690 / BTB_c54300）在苏云金芽孢杆菌407（cry-）导致整个运动轨迹的六到十倍下调，以及鞭毛结构和游泳运动的丧失。cdgL是蜡状芽孢杆菌组所独有的，并且在除 I 组外的所有系统发育簇中都有发现，I 组包含非运动性假丝状芽孢杆菌的分离株。RNA-Seq 数据分析显示cdgL在三基因操纵子中表达，该操纵子具有类似 NupC 的核苷转运蛋白，以及一种推定的糖基转移酶，此前已证明基于转座子的基因失活可产生与cdgL缺失相似的表型。有趣的是，预测所有三种蛋白质都是膜结合的，并且可能在调节B.蜡样群运动性。