5.4.3) Lrp and ArcZ
In Erwinia amylovora , the causal agent of fire blight disease
that devastates apple and pear trees, Lrp modulates several
virulence-associated traits and it is post-transcriptionally regulated
by the Hfq-dependent sRNA ArcZ (Schachterle and Sundin, 2019). ArcZ
interacts with the 103-nt-long 5’UTR of lrp to destabiliselrp mRNA. ArcZ was shown to positively regulate the motility
phenotype and the transcription of flagellar genes indirectly through
Lrp, while directly repressing the translation of flhDC mRNA.
This incoherent feed-forward loop could generate a uniquely shaped
output pulse in flagellar motility in response to variations in Lrp
quantity. Thus, Lrp could temporarily shift motility under specific
environmental conditions, mostly through its regulation of flhDC .
Other sRNAs, such as ArcZ, may be involved in lrp regulation, as
described in E. amylovora . We can therefore postulate that
post-transcriptional regulation of lrp involving sRNAs may be
crucial, even if the sRNA varies.