Efficacy of Bacillus subtilis XZ18-3 as a Biocontrol Agent against Rhizoctonia cerealis on Wheat

Abstract

Rhizoctonia cerealis is a major fungal pathogen of wheat that causes great yield losses in all wheat-growing regions of the world. The biocontrol agent Bacillus subtilis XZ18-3 was investigated for inhibiting R. cerealis growth in wheat. The results of the mycelial growth test showed that the sterile filtrate of B. subtilis XZ18-3 could significantly inhibit the mycelial growth of R. cerealis and cause swelling and rupture of the mycelium. Observation by transmission electron microscopy indicated that the sterile filtrate could penetrate the cellular membrane of Rhizoctoniacerealis, resulting in organelle destruction. The effect of the sterile filtrates on the pathogen cells, shown through fluorescent microscopy using different stains, revealed the mechanism by which the sterile filtrate caused DNA fragmentation, accumulation of ROS and changes in cell membrane permeability. To reach a better treatment of the soil-borne fungi, the components of a wettable powder were screened and an optimised formula determined (30.0% kaolin, 4.0% polyvinyl alcohol, 8.0% Tween-80, 2.0% polyethylene glycol and 100% fermentation broth). A quality index analysis revealed that the wetting powder reached acceptable biological pesticide standards. Pot control experiments showed that the wettable powder of B. subtilis XZ18-3 effectively controlled the pathogens with an efficacy of 88.28%. This study has provided the potential biocontrol agents (BCAs) for wheat sharp eyespot disease.

Compound fermentation supernatants of antagonistic bacteria control Rhizoctonia cerealis and promote wheat growth

“…When the fermentation supernatants were exposed to light for more than 6 h, their antifungal activity gradually decreased. But the inhibition rate was greater than 57% without significant changes, which indicated that the CFS had a strong tolerance to light, which agreed with sterile filtrates treated with illuminated light, and were stable in their activity against the pathogen (Yi et al 2022a). Biological control for plant pathogens is associated with the synthesis of bioactive substances, such as active protein, HCN and hydrolytic enzymes, considered as traits defining biocontrol ability (Liu et al 2014).…”

“…Acidbase treatment: CFS were divided into 7 equal parts, and every part was adjusted the pH to 1, 3, 5, 7, 9, 11 and 13 with 1 mol/l HCl and 1 mol/l NaOH, respectively, and pH 7 treatment was set as control (Hasani et al 2018). Ultraviolet light treatment: CFS were divided into 10 equal parts and placed at a distance of 30 cm under a 20 W UV lamp for 15,30,45,60,75,90,105,120,135 and 150 min, respectively, and the untreated CFS were set as control (Zhao et al 2017); light treatment: CFS were divided into 7 equal parts and placed in the illumination incubator (4000 lx) for light irradiation with 0, 2, 4, 6, 8, 10 and 12 h (Yi et al 2022a). Each test was repeated three times.…”

Treatment with organic manure inoculated with a biocontrol agent induces soil bacterial communities to inhibit tomato Fusarium wilt disease

“…In contrast, several taxa were significantly negatively correlated with Fusarium wilt incidence, including Bacillus , Altererythrobacter , Cryptococcus , and Saprospiraceae . Some species of Bacillus are already used as biocontrol agents against a wide range of fungal pathogens, including Rhizoctonia cerealis , Botrytis cinerea , Penicillium digitatum , and P. italicum ( Chen et al, 2020 ; Samaras et al, 2021 ; Yi et al, 2022 ). BF-treated soil also displayed a high abundance of Altererythrobacter , which is consistent with previous studies showing stable proliferation of the Erythrobacter YH-07 strain (which belongs to Altererythrobacter) after soil inoculation ( Tang et al, 2020 ).…”

Evaluation of the Biocontrol Efficiency of Bacillus subtilis Wettable Powder on Pepper Root Rot Caused by Fusarium solani

“…Zhang et al [ 39 ] reported that the application of a consortium of PGPR strains could reduce the sweet pepper disease, with the improvement of fruit quality and soil properties. Bacillus subtilis XZ18-3 was developed into a wettable powder with a control efficacy of 88.28% against Rhizoctonia cerealis on wheat [ 40 ]. In this work, B. subtilis PTS-394 wettable powder has an excellent and stable biocontrol effect both in pot and field trials and is a potential biocontrol agent for controlling the pepper root rot.…”