Biotechnological potential of bacteria from genera Bacillus Paraburkholderia and Pseudomonas to control seed fungal pathogens

Biocontrol potential of endophytic Bacillus subtilis A9 against rot disease of Morchella esculenta

Introduction

Morchella esculenta is a popular edible fungus with high economic and nutritional value. However, the rot disease caused by Lecanicillium aphanocladii, pose a serious threat to the quality and yield of M. esculenta. Biological control is one of the effective ways to control fungal diseases.

Methods and results

In this study, an effective endophytic B. subtilis A9 for the control of M. esculenta rot disease was screened, and its biocontrol mechanism was studied by transcriptome analysis. In total, 122 strains of endophytic bacteria from M. esculenta, of which the antagonistic effect of Bacillus subtilis A9 on L. aphanocladii G1 reached 72.2% in vitro tests. Biological characteristics and genomic features of B. subtilis A9 were analyzed, and key antibiotic gene clusters were detected. Scanning electron microscope (SEM) observation showed that B. subtilis A9 affected the mycelium and spores of L. aphanocladii G1. In field experiments, the biological control effect of B. subtilis A9 reached to 62.5%. Furthermore, the transcritome profiling provides evidence of B. subtilis A9 bicontrol at the molecular level. A total of 1,246 differentially expressed genes (DEGs) were identified between the treatment and control group. Gene Ontology (GO) enrichment analysis showed that a large number of DEGs were related to antioxidant activity related. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the main pathways were Nitrogen metabolism, Pentose Phosphate Pathway (PPP) and Mitogen-Activated Protein Kinases (MAPK) signal pathway. Among them, some important genes such as carbonic anhydrase CA (H6S33_007248), catalase CAT (H6S33_001409), tRNA dihydrouridine synthase DusB (H6S33_001297) and NAD(P)-binding protein NAD(P) BP (H6S33_000823) were found. Furthermore, B. subtilis A9 considerably enhanced the M. esculenta activity of Polyphenol oxidase (POD), Superoxide dismutase (SOD), Phenylal anineammonia lyase (PAL) and Catalase (CAT).

Conclusion

This study presents the innovative utilization of B. subtilis A9, for effectively controlling M. esculenta rot disease. This will lay a foundation for biological control in Morchella, which may lead to the improvement of new biocontrol agents for production.

Rational management of the plant microbiome for the Second Green Revolution

The Green Revolution of the mid-20th century transformed agriculture worldwide and has resulted in environmental challenges. A new approach, the Second Green Revolution, seeks to enhance agricultural productivity while minimizing negative environmental impacts. Plant microbiomes play critical roles in plant growth and stress responses, and understanding plant-microbiome interactions is essential for developing sustainable agricultural practices that meet food security and safety challenges, which are among the United Nations Sustainable Development Goals. This review provides a comprehensive exploration of key deterministic processes crucial for developing microbiome management strategies, including the host effect, the facilitator effect, and microbe-microbe interactions. A hierarchical framework for plant microbiome modulation is proposed to bridge the gap between basic research and agricultural applications. This framework emphasizes three levels of modulation: single-strain, synthetic community, and in situ microbiome modulation. Overall, rational management of plant microbiomes has wide-ranging applications in agriculture and can potentially be a core technology for the Second Green Revolution.

Comparative Analysis of Microbial Community Diversity and Dynamics on Diseased Tubers During Potato Storage in Different Regions of Qinghai China

Effective storage of potatoes is very important for the food industry. Given the problems involving rotten potatoes and low quality during storage, harvested potatoes from the main potato-producing areas in the Qinghai Plateau were treated by selection and air drying (Group "A") and the others were stored directly as controls (Group "C"). Then, the microbial community structure and diversity of diseased potato tubers from four main production areas were analyzed by high-throughput sequencing technology in different storage stages. The results showed that the community composition and diversity of microbes in different regions and storage periods were different, and the dominant fungi in diseased potato tubers were Boeremia in Huangyuan (HY), Maying (MY) and Zhongling (ZL) and Apiotrichum in Huangzhong (HZ) at the genus level. The dominant bacterial genus was Pseudomonas, but its abundance varied in samples from different regions and storage periods. In the analysis of indicator species, there were some common species and endemic species in each region and period, and the period with the largest number of different species was the third period. Among the four storage periods, the region with the largest number of different species was HZ. Some fungi, especially Fusarium and other potato pathogens, were more abundant in control Group "C" than in treatment Group "A." In the diversity analysis, the α diversity of fungi in Group "C" was higher than that in Group "A," but the α diversity of bacteria in Group "A" was higher than that in Group "C," and there was no obvious regularity with storage time. The β diversity varied significantly among different regions. In addition, through functional prediction analysis, it was found that a plant pathogen was one of the main nutritional types of fungi, which indicated that treatment by selection and drying could significantly reduce phytopathogenic microbe and other microorganisms and could be used as an effective measure for potato storage compared with the prevention and control by drugs that can cause environmental pollution. Further analysis of co-occurrence network showed that pathogenic fungi Fusarium was negatively correlated with pathogenic bacteria Erwinia, and there is also a negative correlation between pathogens and antagonistic microorganisms indicated that there were various symbiotic relationships among microorganisms in diseased potatoes. This study may provide a theoretical basis for biological control of potato cellar diseases and the maintenance of potato quality during long-term storage.