A group of scientists in New Zealand has turned their attention to
Brevibacillus laterosporus (Bl) to determine if the said bacterium can
endophytically live in cabbage plants and potentially reduce costs to fight
off insect pests of brassica species.

Bl is an insecticidal bacterium known to be toxic to different invertebrates
after ingestion. Its isolates were taken from the surface of sterile cabbage
seeds, specifically of the Brassica oleracea var. capitata, and were used to
make colonies in brassica plants grown in the field and laboratory. The
brassica plants placed in the laboratory were inoculated with Bl and were
grown up to the vegetative stage, then the bacterium was gathered from the
leaf, stem and root sections of the seedlings. On the other hand, the
cabbages that were grown under field trial conditions were allowed to
mature. Bl was also harvested from the leaf, stem, and root sections of the
mature plants.

Analysis confirmed the presence of the recovered bacterial isolates. These
were tested on diamondback moths using cabbage seedlings treated with Bl
1951 isolate, which is known to be toxic to the said moth after ingestion.
The scientists observed that there was a significant decrease in the
diamondback moth pupation on the treated plants.

Through confocal microscopy, it was established that Bl was present in the
cabbage root tissue, therefore proving that the bacterium is, in fact,
endophytic. In simpler terms, Bl has the ability to live between living
plant cells of the brassica species. The same endophytic nature of Bl was
also present in other brassica species that were tested: Chinese kale,
oilseed rape, and radish. The confirmation of the Bl's endophytic nature may
lead to future studies to determine if it can substantially reduce the need
for foliar applications of the Bl spores that may lead to reducing control
costs in economically important brassica crops.

[journals.plos.org]