Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Wheat

Abstract

Biocontrol by inoculation with beneficial microbes is a proven strategy for reducing the negative effect of soil-borne pathogens. We evaluated the effects of microbial inoculants BIO-1 and BIO-2 in reducing soil-borne wheat diseases and in influencing wheat rhizosphere microbial community composition in a plot test. The experimental design consisted of three treatments: (1) Fusarium graminearum F0609 (CK), (2) F. graminearum + BIO-1 (T1), and (3) F. graminearum F0609 + BIO-2 (T2). The results of the wheat disease investigation showed that the relative efficacies of BIO-1 and BIO-2 were up to 82.5% and 83.9%, respectively. Illumina MiSeq sequencing revealed that bacterial abundance and diversity were significantly higher ( P < 0.05 ) in the treatment groups (T1 and T2) than in the control, with significantly decreased fungal diversity in the T2 group. Principal coordinates and hierarchical clustering analyses revealed that the bacterial and fungal communities were distinctly separated between the treatment and control groups. Bacterial community composition analysis demonstrated that beneficial microbes, such as Sphingomonas, Bacillus, Nocardioides, Rhizobium, Streptomyces, Pseudomonas, and Microbacterium, were more abundant in the treatment groups than in the control group. Fungal community composition analysis revealed that the relative abundance of the phytopathogenic fungi Fusarium and Gibberella decreased and that the well-known beneficial fungi Chaetomium, Penicillium, and Humicola were more abundant in the treatment groups than in the control group. Overall, these results confirm that beneficial microbes accumulate more easily in the wheat rhizosphere following application of BIO-1 and BIO-2 and that the relative abundance of phytopathogenic fungi decreased compared with that in the control group.

Effects of Two Bacillus Velezensis Microbial Inoculants on the Growth and Rhizosphere Soil Environment of Prunus davidiana

“…This shows that the use of inoculants has a significant positive impact on the bacterial community in the peach rhizosphere, which can slow the decline in microbial richness and diversity in the rhizosphere soil. This is consistent with many studies showing that inoculation with Bacillus can improve the α diversity of plant rhizosphere microorganisms [ 15 , 37 ]. Correlation analysis showed that there was a significant positive correlation between the soil nutrient content and the diversity of bacteria.…”

“…Chen et al [ 14 ] showed that a B. subtilis inoculant changed the relative abundance of the dominant soil phylum, increased the available nitrogen in the soil, and increased the wheat yield by 33.4%. Wang et al [ 15 ] found that inoculation treatments with BIO-1 and BIO-2 significantly enriched beneficial microorganisms such as Sphingomonas , Bacillus , Nocardioides , Rhizobium , Streptomyces , Pseudomonas and Microbacterium and the therapeutic effects on wheat diseases were as high as 82.5% and 83.9%, respectively. Thus, the application of microbial inoculants has been considered an effective strategy to overcome the obstacles of crop succession, improve the structure of microbial communities, and maintain their beneficial functions [ 16 , 17 ].…”

Wheat Microbiome: Structure, Dynamics, and Role in Improving Performance Under Stress Environments

“…Moreover, the bacterial inocculents Paenibacillus jamilae and Bacillus amyloliquefaciens were observed to reduce (82 and 83%, respectively) soil-borne wheat diseases and significantly affect the rhizosphere microbial community structure. The beneficial rhizosphere bacteria like Sphingomonas , Bacillus , Nocardioides , Rhizobium , Streptomyces , Pseudomonas , and Microbacteriu and the beneficial fungal genera like Chaetomium , Penicillium , and Humicola were enriched, whereas the pathogenic fungal strains, Fusarium and Gibberella were restricted upon treatment of Paenibacillus jamilae and Bacillus amyloliquefaciens ( Wang et al, 2021 ). Likewise, Stenotrophomonas maltophilia, Bacillus cereus , and richoderma harzianum showed biocontrol activity against F. graminearum ( Dal Bello et al, 2002 ).…”

Response of Bacterial Community to the Occurrence of Clubroot Disease in Chinese Cabbage

“…Besides in the HR soil, the differential abundance of Pseudomonas was also observed in the HR cabbage roots, but no significant dominant bacterial species were found in this study. N. caerulescens was identified as the major differential bacteria in the cabbage roots belonging to the Nocardioides genus, which has been revealed to possess resistance to various plant diseases and has been considered as the candidate biocontrol reagent and biofertilization (Battini et al, 2016 ; Wang et al, 2021 ). In a prior yield experiment, soil pH was identified as a critical factor that markedly influenced the biocontrol effect of Heteroconium chaetospira on clubroot disease together with moisture content and pathogen density (Narisawa et al, 2005 ).…”