Comparative Genomics of Myxobacterial Chemosensory Systems

Abstract: Chemosensory systems (CSS) are among the most complex organizations of proteins functioning cooperatively to regulate bacterial motility and other cellular activities. These systems have been studied extensively in bacteria, and usually, they are present as a single system. Eight CSS, the highest number in bacteria, have been reported in Myxococcus xanthus DK1622 and are involved in coordinating diverse functions. Here, we have explored and compared the CSS in all available genomes of order Myxococcales. Myxococcales members contain 97 to 476 twocomponent system (TCS) proteins, which assist the bacteria in surviving and adapting to varying environmental conditions. The number of myxobacterial CSS ranges between 1 and 12, with the largest number in family Cystobacteraceae and the smallest in Nannocystaceae. CheA protein was used as a phylogenetic marker to infer evolutionary relatedness between different CSS, and six novel CSS (“extra CSS” [ECSS]) were thus identified in the myxobacteria besides the previously reported Che1 to Che8 systems from M. xanthus. Che1 to Che8 systems are monophyletic to deltaproteobacteria, whereas the newly identified ECSS form separate clades with different bacterial classes. The comparative modular organization was concordant with the phylogeny. Four clusters lacking CheA proteins were also identified via CheB-based phylogenetic analysis and were categorized as accessory CSS (ACSS). In Archangium, an orphan CSS was identified, in which both CheA and CheB were absent. The novel, accessory, and orphan multimodular CSS identified here suggest the emergence of myxobacterial CSS and could assist in further characterizing their roles.

Gaurav Sharma, Indu Khatri, and Srikrishna Subramanian. Comparative Genomics of Myxobacterial Chemosensory Systems. Journal of bacteriology, 200(3): 2017.
@article { bib:2017_Myxo,
author = { Gaurav Sharma and Indu Khatri and Srikrishna Subramanian },
title = { Comparative Genomics of Myxobacterial Chemosensory Systems },
journal = { Journal of bacteriology },
volume = { 200 },
number = { 3 },
year = { 2017 },
doi = { 10.1128/JB.00620-17 },
Myxo screenshot