Isolation and characterization of Bacillus sp. strain BC01 from soil displaying potent antagonistic activity against plant and fish pathogenic fungi and bacteria

Abstract

Fungal and bacterial pathogens infect a diverse range of hosts including various plant and animal species. Fungal and bacterial diseases, especially of plants and aquatic animals, such as fish, lead to significant damage to crops and aquaculture, respectively, worldwide. The present study was conducted to isolate and characterize potent Bacillus strains with significant antagonistic activity against the major plant and fish pathogenic fungi and bacteria. We randomly collected 22 isolates of Bacillus from the soil, rhizosphere, and sediment from different parts of Bangladesh. Initial characterization, based on in vitro antagonistic activity on the culture plate, resulted in the selection of four gram-positive Bacillus sp. isolates. Among these, the isolate BC01, obtained from soil demonstrated the highest broad-spectrum anti-bacterial and anti-fungal activities. We confirmed the genus of BC01 to be Bacillus by morphological and biochemical tests as well as using molecular data analysis tools, including the study of 16s rDNA, phylogenetic relationship, and evolutionary divergence scores. The isolate significantly inhibited the mycelial growth of the plant pathogen, Penicillium digitatum and fish pathogen, Aphanomyces invadans in vitro. The anti-bacterial effect of the isolate was also evaluated against Pseudomonas spp. and Xanthomonas spp., the two deadliest plant pathogens, and Aeromonas veronii, Pseudomonas fluorescens, and Streptococcus iniae, three major fish pathogens that are primarily responsible for global aquaculture loss. The results of the present study could pave the way for developing potent drugs to combat microbial infection of plants and fish.

Effects of Bacillus velezensis Supplementation on the Growth Performance, Immune Responses, and Intestine Microbiota of Litopenaeus vannamei

“…Many strains of some Bacillus sp. are currently used as probiotic dietary supplements in aquatic animal feeds (Foysal and Lisa, 2018;Kewcharoen and Srisapoome, 2019;Kuebutornye et al, 2019;Zhai et al, 2019;Zhou et al, 2019;Liu et al, 2020). These probiotics not only produce certain essential micronutrients that promote better growth and feed utilization of the hosts (Xie et al, 2019) but also participate in the digestion processes that break down nutrients, such as carbohydrates, proteins, and lipids by producing extracellular enzymes (e.g., amylase, trypsin, lipase) (Wang et al, 2007;Zhang et al, 2020).…”

Leptospirosis and Coinfection: Should We Be Concerned?

“…During arbovirus-related outbreaks, a systematic diagnostic protocol should include Bacteria belonging to the genus Bacillus are Gram-positive, rod-shaped, spore-forming, motile and easily found in the soil. Although used to protect plants and animals from microbial infection by secretion of antibiotics, volatile compounds, and enzymes [147], it was not considered pathogenic to humans, except for a few strains such as Bacillus anthracis that can cause anthrax in humans and animals. Humans usually get infected during contact with infected animals or spore ingestion due to the inhalation of spores from soil management activities [148].…”

Emerging trends of culturing microalgae for fish‐rearing environment protection

“…Hence, the biomass harvested by sedimentation, centrifugation, flocculation, and filtration, all of which are widely used in microalgae industry, can contain a number of wastewater‐borne microbes. Since some of the microbes, such as Streptococcus iniae , Pseudomonas aeruginosa , Aeromonas hydrophila , and Vibrio harveyi , are pathogenic to aquatic animals, the biomass may not be directly exploited as fish diet for aquaculture practice 10,34 . Even if the pathogenic microbes contained in biomass can be killed by sterilization, the toxins secreted by some bacteria and fungi still pose a serious threat to the survival of aquatic animals.…”