The CRISPR-Cas system of Prokaryotes is an adaptive immune defense
mechanism to protect themselves from invading genetic elements (e.g.
phages and plasmids). Studies that describe the genetic organization of
these prokaryotic systems have mainly reported on the Enterobacteriaceae
family (now reorganized within the order Enterobacteriales). For some
genera, data on CRISPR-Cas systems remain poor, as in the case of
Serratia (now part of the Yersiniaceae family) where data are limited to
a few genomes of the species marcescens. This study describes the
detection, in silico, of CRISPR loci in 146 Serratia complete genomes
and 336 high-quality assemblies available for the species ficaria,
fonticola, grimesii, inhibens, liquefaciens, marcescens, nematodiphila,
odorifera, oryzae, plymuthica, proteomaculans, quinivorans, rubidaea,
symbiotic, and ureilytica. Apart from subtypes I-E and I-F1, which had
previously been identified in marcescens, we report that of I-C and the
variants I-ES1, I-ES2 and I-F1S1. Analysis of the genomic contexts for
CRISPR loci revealed mdtN-phnP as the region mostly shared (grimesii,
inhibens, marcescens, nematodiphila, plymuthica, rubidaea, and Serratia
sp.). Three new contexts detected in genomes of rubidaea and fonticola
(puu genes-mnmA) and rubidaea (osmE-soxG and ampC-yebZ) were also found.
Plasmid and/or phage origin of spacers was also established.