In order to resolve the key genes for weed control by Trichoderma polysporum at the genomic level, we extracted the genomic DNA and sequenced the whole genome of T. polysporum strain HZ-31 on the Illumina Hiseq platform. The raw data was cleaned up using Trimmomatic and checked for quality using FastQC. The sequencing data was assembled using SPAdes, and GeneMark was used to perform gene prediction on the assembly results. The results showed that the genome size of T. polysporum HZ-31 was 39,325,746 bp, with 48% GC content, and the number of genes encoded was 11,998. A total of 148 tRNAs and 45 rRNAs were predicted. A total of 782 genes were annotated in the Carbohydrase Database, 757 genes were annotated to the Pathogen-Host Interaction Database, and 67 gene clusters were identified. In addition, 1023 genes were predicted to be signal peptide proteins. The annotation and functional analysis of the whole genome sequence of T. polymorpha HZ-31 provide a basis for the in-depth study of the molecular mechanism of its herbicidal action and more effective utilization for weed control.

Trichoderma polysporum (Link) Rifai HZ-31 fermentation broth was separated and purified by extraction, column chromatography, and high-performance liquid chromatography. Four monomer compounds with strong herbicidal activity were obtained: p-hydroxyphenyl-2,3-dihydroxypropyl ether, o-hydroxy-3-carbonyl-1-phenylpropanol, 1,8-propanediol o-xylene, and 2-3-dihydroxypropyl propionate. The biological activity verification test indicated that the four monomer compounds could inhibit the germination of wild oat (Avena fatua L.) and canola (Brassica napus L.) seeds. Of the four, compound 3 (1,8-propanediol o-xylene) had obvious inhibitory effects on the germination of A. fatua and B. napus seeds, with inhibition rates of 83.33% and 86.67%, respectively. Therefore, the identification of this monomer compound lays a foundation for the further development of a novel microbial herbicide by directly utilizing it and developing new derivatives with herbicidal functions as lead compounds.

Biological control is a scientific management method used in modern agricultural production, and microbially derived biopesticides are one effective method with which to control weeds in agricultural fields. In order to determine the key genes for weed control by Trichoderma polysporum, transcriptome sequencing was carried out by high-throughput sequencing technology, and the strains of T. polysporum HZ-31 infesting Avena fatua L. at 24, 48, and 72 h were used as the experimental group, with 0 h as the control group. A total of 690,713,176 clean reads were obtained, and the sequencing results for each experimental group and the control group (0 h) were analyzed. In total, 3464 differentially expressed genes were found after 24 h of infection with the pathogen, including 1283 down-regulated genes and 2181 up-regulated genes. After 48 h of infection, the number of differentially expressed genes was 3885, of which 2242 were up-regulated and 1643 were down-regulated. The number of differentially expressed genes after 72 h of infection was the highest among all the groups, with 4594 differentially expressed genes, of which 2648 were up-regulated and 1946 were down-regulated. The up-regulated genes were analyzed by GO and KEGG, and the results showed that the up-regulated differentially expressed genes were mainly enriched in the biosynthesis of phenylalanine, tyrosine, and tryptophan; the degradation of aromatic compounds; methane metabolism; and other pathways. Among them, the PHA2, GDH, ADH2, and AROF genes were significantly enriched in the above-mentioned pathways, so they were hypothesized to play an important role in the synthesis of the herbicidally active substances of T. polysporum HZ-31. The results of this study can provide a theoretical basis for further studies on the pathogenicity of T. polysporum to A. fatua L., and accelerate the development and utilization of new and efficient bioherbicides.

The aim of this study was to investigate the potential and pathogenic mechanism of the pathogenic fungus Alternaria alternata strain GD-011-B against four major agricultural weeds on the Tibetan plateau, and to lay a foundation for the commercial production and application of this strain. The mycelial masses had herbicidal activity against the isolated leaves of the weeds Chenopodium album, Elsholtzia densa, Malva verticillata, and Amaranthus retroflexus L., with a descending herbicidal activity order of M. verticillata > E. densa > A. retroflexus > C. album. The fermentation broth also showed herbicidal activity by treating the whole plants of these four weeds in the descending order of C. album > E. densa > M. verticillata > A. retroflexus. Scanning electron microscopy revealed that GD-011-B mycelia invaded the inner part of the leaf of A. retroflexus through the stomata and epidermal tissue gap and extended to the back, damaging the leaf epidermis and tissues and sporulating on the leaf surface, ultimately resulting in leaf disease. The fermentation broth of pathogen GD-011-B was not pathogenic to Vicia faba L., Pisum sativum L., Hordeum vulgare L., or Triticum aestivum L., but it was slightly pathogenic to Brassica napus L. Therefore, Alternaria alternata can be used as a herbicidal microorganism with high potential for biological control of four major agricultural weeds on the Tibetan plateau.

The herbicidal efficacy and crop safety of Fusarium acuminatum strain HL-29, an endophytic fungus isolated from infected Amaranthus retroflexus in Qinghai Province, were evaluated. In vitro leaf assays demonstrated its pathogenicity against four broadleaf weeds, with efficacy ranked as follows: Elsholtzia densa = Senecio vulgaris = Chenopodium album > Malva verticillata. Pot trials further confirmed that the HL-29 fermentate caused 100% disease incidence in S. vulgaris, C. album, and E. densa. Notably, the strain showed no pathogenicity toward seven major local crops, indicating excellent selectivity. Scanning electron microscopy (SEM) revealed key morphological changes during the infection process on C. album leaves. These results establish F. acuminatum HL-29 as a promising biocontrol candidate against broadleaf weeds in the Qinghai–Tibet Plateau, providing a theoretical foundation for developing alpine-adapted mycoherbicides.

The herbicidally active Botrytis strain HZ-011 was isolated from naturally infected leaves of Rumex patientia L., and previous studies found that strain HZ-011 exhibits highly effective herbicidal effects against the broadleaf weeds Amaranthus...