Study of growth-improving and sporophore-inducing endobacteria isolated from Pleurotus pulmonarius

Abstract

Several Pleurotusspecies (oyster mushrooms) are commercially cultivated in India owing to the favorable tropical agro-climatic conditions. However, there are only a few studies on the microbiome of mushrooms, especially oyster mushrooms. The aim of this study was to assess the effect of endophytic bacteria on mycelial growth, spawning, sporophore development, and proximate composition of P. pulmonarius. We isolated several bacterial strains from the sporophores of P. pulmonarius and assessed the in vitro production of indole acetic acid, ammonia, and siderophores. The selected bacteria were individually supplemented with spawn, substrate, or both for sporophore production. Three of 130 isolates were selected as mycelial growth-promoting bacteria in both solid and submerged fermentation. These bacterial isolates were identi ed through Gram staining, biochemical characterization, and 16S rRNA sequencing. Isolate PP showed 99.24% similarity with Priestia para exa, whereas isolates PJ1 and PJ2 showed 99.78% and 99.65% similarities, respectively, with Rossellomorea maris avi. The bacterial supplementation with spawn, substrate, or both, increased the biological e ciency (BE) and nutrient content of the mushrooms. The bacterial supplementation with substrate augmented BE by 64.84%, 13.73%, and 27.13% using PJ2, PP, and PJ1, respectively; under similar conditions of spawn supplementation, BE wasincreased by 15.24%, 47.03%, 48.10%, respectively. Overall, the supplementation of endophytic bacteria to improve oyster mushroom cultivation may open a new avenue for sustainable agricultural practices in the mushroom industry.