Abstract
In fluorescent pseudomonads, the Gac/Rsm signal transduction pathway controls secondary metabolism to suppress of fungal root pathogens via the expression of regulatory small RNAs (sRNAs). Because of its high cost, this pathway needs to be turned off in response to environmental stress. However, little is known about its underlying molecular mechanisms. In this study, it has been demonstrated that Lon protease negatively regulated the Gac/Rsm cascade in Pseudomonas protegens. It has also been shown that the alarmone ppGpp (guanosine tetraphosphate) appears to be essential for sustaining epiphytic fitness and biocontrol activity of P. protegens.
