Biological Control of Tomato Bacterial Wilt, Kimchi Cabbage Soft Rot, and Red Pepper Bacterial Leaf Spot Using Paenibacillus elgii JCK-5075

Abstract

The over and repeated use of chemical bactericides to control plant bacterial diseases has resulted in unwanted effects, such as environmental pollution, residual toxicity, and resistance buildup in bacterial pathogens. Many previous studies have aimed to develop biological control agents to replace chemical bactericides. In this study, the antibacterial efficacy of the fermentation broth of Paenibacillus elgii JCK-5075 and its antibacterial compounds were evaluated against plant pathogenic bacteria, using both in vitro and in vivo bioassays. Pelgipeptins (PGPs) A, B, C, and D that were isolated from P. elgii JCK-5075 displayed broad-spectrum antibacterial activity against various plant pathogenic bacteria. The fermentation broth of P. elgii JCK-5075, at 5-fold dilution, effectively suppressed the development of tomato bacterial wilt, Kimchi cabbage soft rot, and red pepper bacterial leaf spot in pot experiments with control values of 81, 84, and 67%, respectively. PGP-A and C, at 200 μg/ml, were also found to markedly reduce the development of Kimchi cabbage bacterial soft rot by 75% and tomato bacterial wilt by 83%, respectively, and their disease control efficacy was comparable to that of oxolinic acid with control values of 81 and 85%, respectively. Additionally, the antibacterial activity of PGP-C was found to be directly correlated with membrane damage mechanisms. These results indicates that P. elgii JCK-5075 producing PGPs could be used as a biocontrol agent for the control of plant bacterial diseases. This is the first report on the in vitro and in vivo antibacterial activity of PGPs against bacterial plant pathogens.

Streptomyces sp. JCK-6131 Protects Plants Against Bacterial and Fungal Diseases via Two Mechanisms

“…The antimicrobial activity of the fermentation filtrate of Streptomyces sp. JCK-6131 was examined against all test microorganisms using a broth dilution method according to previous reports for bacteria ( Le et al, 2020 ) and fungi ( Kim et al, 2020 ). A serial two-fold dilution of the fermentation filtrate (10, 5, 2.5, 1.25, 0.63, 0.31, 0.16, and 0.08%) was prepared for these assays.…”

“…The inoculated plants were kept in the dark for 24 h and then transferred to an incubation room at 30°C and 75% RH with 12 h daylight per day for 10 days. The disease index was graded on the following scale: 0 = no leaf symptom, 1 = one leaf wilted, 2 = two or three leaves wilted, 3 = more than four leaves wilted, and 4 = plant dead ( Le et al, 2020 ).…”

Suppression of Bacterial Leaf Spot by Green Synthesized Silica Nanoparticles and Antagonistic Yeast Improves Growth, Productivity and Quality of Sweet Pepper

“…Disease severity was recorded using the following scale according to Le et al, [ 28 ]: 1 = symptomless, 2 = a few necrotic spots on a few leaflets, 3 = a few necrotic spots on many leaflets, 4 = many spots with coalescence on few leaflets, 5 = many spots with coalescence on many leaflets, 6 = severe disease and leaf defoliation, and 7 = plant dead. The disease severity scale was used based on leaf spot disease development in which infected plants were recorded in each replicate.…”

Deciphering the Relationship Between Cycloheximides Structures and Their Different Biological Activities

“…Identification of JCK-6092 was performed using 16S rRNA gene sequencing as conducted by Le et al (2020) , with slight modifications. Briefly, PCR amplification was performed using specific primer pair sets for the subsequent sequencing of 16S rRNA (Genotech Co., Daejeon, South Korea).…”