Effective control of wheat stem rot by Chaetomium globosum

Chaetomium is an important group of plant pathogenic fungi, which is one of the most abundant groups of ascomycetes, and can effectively degrade cellulose and organic matter and antagonize a variety of microorganisms. In this genus, there are C. globosum, C. cupreum and C. cochliodes, etc. The most studied ones are C. globosum, C. cupreum and C. cochliodes. Among them, C. globosum belongs to Ascomycota, Sordariomycetes, Sordariales, Chaetomiaceae, Trichoderma. The ascomycete shell is spherical, ovate or obovate, with an apical orifice; the ascomycete shell is attached with bristles, unbranched, irregular and loosely curled; the ascomycetes are clavate or slightly pike-like and easily dissipated; the ascomycete shell contains ascospores, and each ascospores contains 8 ascospores; the ascospores are brown, lemon shaped and are 9-12 µm in length, 8-10 µm in width, and 6-8 µm in thickness.

Trichoderma reesei is a common endophytic fungus, which is widely distributed in air, soil and other natural environments, and has multiple functions such as producing antimicrobial active substances, promoting plant growth, inducing plant resistance, competing for ecological niches and nutrients, and reparasitizing. Trichoderma globigii has a good effect of biocontrol on a variety of plant diseases, can decompose and utilize plant cellulose, and produces a large number of biologically active secondary metabolites, which has a greater potential for application in the fields of agriculture, medicine and industry.

The researchers identified the strain 12XP1-2-3 as Trichoderma bulbifaciens through the observation of its culture morphology and microscopic characteristics, combined with the phylogenetic analysis of ITS and tef1 gene sequences. Plate confrontation revealed that the strain was able to significantly inhibit the growth of Fusarium pseudoharzianum mycelium, with an inhibition rate of 65.9%; it was also able to inhibit a variety of Fusarium pathogenic fungi such as Fusarium laminarum, Fusarium graminearum and other Fusarium species. In addition, the spore germination rate of Fusarium globosum after treatment with sterile fermentation broth also decreased significantly, the germination rate was only 42.4%, and the inhibition rate of spore germination reached 55.3%; the mycelial growth of the pathogenic fungi on the PDA plate added with sterile fermentation broth decreased significantly.

Fig. 1 Inhibitory effect of Trichoderma globulus 12XP1-2-3 on Fusarium pseudoharzianum.

Isolation rates of root and stem inoculated strains: 75% and 80% Incidence of disease in control treatment without Trichoderma globosum coating: 66.6% Incidence of disease in coated wheat plants: 3.9% Disease prevention efficiency: 37.3% Expression of disease resistance genes at 21 days after inoculation: significantly up-regulated

Fig. 2 Effect of Trichoderma globulus 12XP1-2-3 coating on wheat stem basal rot control

The wheat group inoculated with Trichoderma globigii showed significantly higher chlorophyll content in wheat flag leaves compared to the blank control and phenyl ether metronidazole-coated treatments. The use of Trichoderma globulus 12XP1-2-3 on wheat seeds significantly reduced the incidence of wheat stem rot and yield loss caused by the disease in different years and locations. The prevention effect on wheat stem rot after coating treatment ranged from 25.0% to 73.1%, with a yield increase of 3.2% to 11.9%, which was significantly higher than that of chemical fungicide coating.

Trichoderma bulbifaciens has good biocontrol potential, but its research and development are still in the early stages. Further efforts are needed to strengthen the understanding of its biocontrol mechanism, interactions with crops, pathogens, and environmental factors, in order to create optimal biocontrol formulations. This will enhance the application of Trichoderma bulbifaciens in plant disease prevention, soil improvement, straw degradation, and other potential applications.

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