The insect- and plant-associated life of Pseudomonas protegens CHA0 are preserved following serial passage by means of insect larvae

Abstract

The plant-beneficial bacterium Pseudomonas protegens CHA0 (CHA0) is extensively studied for the organic management of soil-borne plant illnesses. Beyond its root-colonising capabilities, CHA0 may also infect and kill insect larvae and thus displays a multi-host life-style shared with different plant- and insect-colonising micro organism. To higher perceive the robustness of this multi-host life-style, we subjected CHA0 to 10 consecutive passages by means of larvae of the pest insect Plutella xylostella by way of repeated cycles of insect colonisation and killing forcing it into an insect-only life-style. Overall, serial passaging didn’t lead to constant modifications in insect killing pace, larval or root colonisation, plant safety effectivity, microbial antagonism or in vitro development. This means that its multi-host life-style was conserved following serial passage. Nonetheless, a couple of independently passaged strains confirmed a rise in larval killing pace, which in a single case is likely to be linked to choline uptake. To disentangle modifications particular to the insect host from these arising because of the experimental system itself, we carried out parallel serial passages by means of the identical system whereas omitting the insect host. In a few of these strains, publicity to the background of the system led to modifications in microbial antagonism and in in vitro development, which probably are related to mutations in areas encoding for regulatory techniques. Our findings point out that P. protegens CHA0 stays phenotypically steady in advanced environments comparable to an insect host, suggesting that the multi-host life-style may additionally be conserved when utilized within the area and supporting CHA0’s potential for dependable biocontrol efficiency towards each plant illnesses and bug pests.