The genome sequence of hairy root Rhizobium rhizogenes strain LBA9402.
Bioinformatics analysis suggests the presence of a new opine system in
the agropine Ri plasmid
Abstract
We report here the complete genome sequence of the Rhizobium rhizogenes
(formerly Agrobacterium rhizogenes) strain LBA9402 (NCPPB1855rifR), a
pathogenic strain causing hairy root disease. In order to assemble a
complete genome we obtained short-reads from Illumina sequencing as well
as long-reads from Oxford Nanopore Technology sequencing. The genome
consists of a 3,958,212 bp chromosome, a 2,005,144 bp chromid (secondary
chromosome) and a 252,168 bp Ri plasmid (pRi1855), respectively. The
primary chromosome was very similar to that of the avirulent biocontrol
strain K84, but the chromid showed a 724 kbp deletion accompanied by a
large 1.8 Mbp inversion revealing the dynamic nature of these secondary
chromosomes. The sequence of the agropine Ri plasmid was compared to
other types of Ri and Ti plasmids. Thus we identified the genes
responsible for agropine catabolism, but also a unique segment adjacent
to the TL-region that has the signature of a new opine catabolic gene
cluster including the three genes that together encode an opine
dehydrogenase. Our sequence analysis also revealed a novel gene at the
very right end of the TL-DNA, which is unique for the agropine Ri
plasmid. The protein encoded by this gene was most related to the
succinamopine synthases of chrysopine and agropine Ti plasmids and thus
may be involved in synthesis of the unknown opine that can be degraded
by the adjacent catabolic cluster. The available sequence will
facilitate the use of R. rhizogenes and especially LBA9402 in both the
laboratory and for biotechnological purposes.