Scientists Prove Endophytic Ability of Brevibacillus laterosporus Bacterium in Brassica Plants

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.

Read the full paper in PLOS One.