Endophytes represent a ubiquitous and magical world in plants. Almost all plant species studied by different researchers have been found to harbor one or more endophytes, which protect host plants from pathogen invasion and from adverse environmental conditions. They produce various metabolites that can directly inhibit the growth of pathogens and even promote the growth and development of the host plants. In this review, we focus on the biological control of plant diseases, aiming to elucidate the contribution and key roles of endophytes and their metabolites in this field with the latest research information. Metabolites synthesized by endophytes are part of plant disease management, and the application of endophyte metabolites to induce plant resistance is very promising. Furthermore, multi-omics should be more fully utilized in plant–microbe research, especially in mining novel bioactive metabolites. We believe that the utilization of endophytes and their metabolites for plant disease management is a meaningful and promising research direction that can lead to new breakthroughs in the development of more effective and ecosystem-friendly insecticides and fungicides in modern agriculture.

Anthracnose, caused by the fungus Collectotrichum fructicola (C. fructicola), is a major disease affecting the quality and yield of Camellia oleifera (C. oleifera); it reduces C. oleifera yield by 40%–80%. Bacillus subtilis (B. subtilis) YL13 is an antagonistic endophytic bacteria strain isolated from healthy C. oleifera leaves. This study was aimed at investigating the potential of YL13 for the biocontrol of C. oleifera anthracnose and the possible mechanisms involved. In in vitro assays, YL13 demonstrated remarkable antagonistic activity of C. fructicola. Its cell-free filtrates displayed antagonistic activity, which suggested that the metabolites of YL13 might play important roles. In vivo tests showed that the disease index of YL13-treated plants was obviously reduced under greenhouse conditions. YL13 secretes a variety of bioactive metabolites, including protease, cellulase, and siderophore, which might participate in the resistance to C. fructicola. In addition, C. oleifera treated with the fermentation broth of YL13 demonstrated different defense responses, e.g., accumulation of hydrogen peroxide (H₂O₂) and activation of the defense-related enzyme peroxidase (POD), which might contribute directly or indirectly to overcome external stresses. The significant biocontrol effect and host defense-induction activity of YL13 suggested that this B. subtilis strain as well as its metabolites have the potential to be exploited as microbial control agents for the efficient management of C. oleifera anthracnose.

Camellia oleifera (C. oleifera) is one of the four main, woody, edible oil tree species in the world, while C. oleifera anthracnose is mainly caused by the fungus Colletotrichum fructicola (C. fructicola), which severely affects the yield of C. oleifera and the quality of tea oil. Bacillus velezensis (B. velezensis) CSUFT-BV4 is an antagonistic endophytic bacterium isolated from healthy C. oleifera leaves. This study aimed to investigate the biocontrol potential of strain CSUFT-BV4 against C. oleifera anthracnose and its possible functional mechanism, and to determine its growth-promoting characteristics in host plants. In vitro, CSUFT-BV4 was shown to have efficient biofilm formation ability, as well as significant functions in the synthesis of metabolic substances and the secretion of probiotic substances. In addition, the CSUFT-BV4 fermentation broth also presented efficient antagonistic activities against five major C. oleifera anthracnose pathogens, including C. fructicola, C. gloeosporioides, C. siamense, C. camelliae, and C. kahawae, and the inhibition rate was up to 73.2%. In vivo, it demonstrated that the growth of C. oleifera treated with CSUFT-BV4 fermentation broth was increased in terms of stem width, plant height, and maximum leaf area, while the activities of various defense enzymes, e.g., superoxide dismutase (SOD), phenylalanine aminotransferase (PAL), and polyphenol oxidase (PPO), were effectively increased. The remarkable antagonistic activities against C. oleifera anthracnose, the growth-promoting characteristics, and the induction of host defense responses indicate that endophytic bacterium CSUFT-BV4 can be effectively used in the biological control of C. oleifera anthracnose in the future, which will have a positive impact on the development of the C. oleifera industry.

Dalbergia odorifera (D. odorifera), commonly named the fragrant rosewood, is one of the second-level protected wild plants in China, and one of 34 species of rosewood in five genera and eight categories in the National Standard of China. As a kind of traditional Chinese medicine (TCM), it plays an important role in the pharmaceutical industry, including the treatment of cardiovascular diseases, rheumatic pain, etc. With the continuous expansion of the planting area of D. odorifera, the diseases and pests of D. odorifera become more and more serious, among which leaf-eating pests are the most serious. In this study, ultraviolet rays and microwaves were used to mutagenize Beauveria bassiana (B. bassiana) strain HNCMBJ-P-01, and excellent mutant strains with high spore yield and high virulence were screened out, and then they were prepared into a wettable powder for forest control experiments to study their biocontrol effects. The virulence screening test showed that the virulence of strain HBWB-44 was the strongest, and the 10 day corrected mortality rate was 80.00%, and the lethal time was 5.622 days. The results of biological control test showed that the control effect of B. bassiana wettable powder 100 times solution reached 60.89%, second only to the botanical fungicide matrine. Generically, The B. bassiana that we screened and mutated showed a good killing effect on Plecoptera bilinealis (P. bilinealis), and the wettable powder produced by it showed a good control effect on the leaf-eating pests of D. odorifera. The application of fungal insecticides in plantations has a good prospect for controlling the occurrence of leaf-eating pests of D. odorifera.

Phosphorus is a crucial nutrient for plant growth, but only a limited quantity is typically accessible in the soil for plants to absorb directly. Phosphate-solubilizing bacteria (PSB) can convert inorganic phosphorus compounds into forms that are more readily usable for plant nutrition. Our previous research has verified the function of Pediococcus pentosaceus PSM16 in degrading phytic acid. On this basis, we further explored the phosphorus-solubilizing capacity of PSM16 and evaluated its potential for practical application in this study. The results indicated that PSM16 significantly enhanced phosphorus utilization, not only enriching the environment with bioavailable phosphorus but also lowering the environmental pH and conductivity. These changes are instrumental in enhancing soil fertility, providing favorable conditions for plant growth, and stimulating seed germination. Through whole-genome sequencing of PSM16, we have identified key genes associated with the production of acid phosphatase. Specifically, the genes of GM000834, GM000917, GM000925, and GM000974 are implicated in PSM16’s phosphorus solubilization function, likely through the production of phosphatase enzymes. Moreover, we have discovered that the phosphatases T.fus-QOS58989.1, A.cae-WP_156200763, M.the-SNW17984, N.gly-GGP12115, T.chr-SDQ48339.1, and T.chr-SDQ90039.1 are homologous to the aforementioned proteins and are present in compost, as confirmed by our informatics analysis. This presence in compost suggests their potential for real-world agricultural applications. This research presents promising candidate strains for the development of phosphorus-degrading bacterial agents, which could increase the efficiency of phosphorus fertilizers and contribute to sustainable agricultural practices. This strategy is not only effective but also environmentally benign and cost-effective, offering a valuable contribution to the field of agricultural biotechnology. IMPORTANCE: This study sheds light on the transformative power of the PSM16 strain, a paragon of phosphorus solubilization that adeptly converts inert phosphorus into a form that is readily absorbed by plants. In this way, it not only elevates the levels of available phosphorus in the environment but also enriches the soil fertility, supporting the healthy growth of plants. The strategic application of PSM16 in tandem with phosphorus fertilizers promises to enhance the utilization rates of these fertilizers, reinforcing sustainable agricultural initiatives and alleviating the environmental pressures caused by excessive application. In addition, the study has uncovered a trove of strains that hold promise for the development of safe dephosphorylating bacterial agents. These agents are poised to deliver an economical, efficient, and eco-friendly alternative, encapsulating a commitment to agricultural advancement that is both responsible and resourceful.

Zearalenone (ZEN), a non-steroidal estrogenic mycotoxin produced by Fusarium graminearum species, poses a significant threat to both human food safety and animal feed quality. In this study, we isolated a strain, designated as Bacillus licheniformis YJ25, from a contaminated moldy corn sample, demonstrating substantial effectiveness in removing ZEN. Our findings revealed that YJ25’s ZEN removal occurs primarily through cell wall adsorption, with enzymatic degradation representing a potential mechanism. In practical applications, enzymatic degradation may yield metabolites with heightened toxicity. However, liquid chromatography–mass spectrometry (LC–MS) analysis revealed that ZEN was not converted into α-/β-zearalenol (α-/β-ZEL) or α-/β-zearalanol (α-/β-ZAL) by YJ25, substantiating the safety profile of YJ25 in the removal of ZEN. Our mechanistic investigations revealed that the cell wall components peptidoglycan and teichoic acid serve as the primary binding sites for ZEN adsorption. Fourier-transform infrared spectroscopy (FTIR) analysis identified O-H, C-H, C=O, and C-O as the principal functional groups participating in the cell wall adsorption process. These investigations establish a scientific foundation for the prospective application of this strain as an efficient biological detoxification agent in food and feed safety management systems.