Effects of Trichoderma asperellum 6S-2 on Apple Tree Growth and Replanted Soil Microbial Environment

Abstract

Trichoderma asperellum strain 6S-2 with biocontrol effects and potential growth-promoting properties was made into a fungal fertilizer for the prevention of apple replant disease (ARD). 6S-2 fertilizer not only promoted the growth of Malus hupehensis Rehd seedlings in greenhouse and pot experiments, but also increased the branch elongation growth of young apple trees. The soil microbial community structure changed significantly after the application of 6S-2 fertilizer: the relative abundance of Trichoderma increased significantly, the relative abundance of Fusarium (especially the gene copy numbers of four Fusarium species) and Cryptococcus decreased, and the relative abundance of Bacillus and Streptomyces increased. The bacteria/fungi and soil enzyme activities increased significantly after the application of 6S-2 fertilizer. The relative contents of alkenes, ethyl ethers, and citrullines increased in root exudates of M. hupehensis Rehd treated with 6S-2 fertilizer and were positively correlated with the abundance of Trichoderma. The relative contents of aldehydes, nitriles, and naphthalenes decreased, and they were positively correlated with the relative abundance of Fusarium. In addition, levels of ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N), available phosphorus (AP), available potassium (AK), organic matter (SOM), and pH in rhizosphere soil were also significantly related to changes in the microbial community structure. In summary, the application of 6S-2 fertilizer was effective in alleviating some aspects of ARD by promoting plant growth and optimizing the soil microbial community structure.

Application of Trichoderma asperellum in apple trees as a growth regulator and antagonist for the control of Alternaria sp.

“…The benefit of Trichoderma as plant growth regulator was also reported in wheat growing with T. reesei, with increased numbers of shoots, higher weight of dried and fresh shoots, higher root length and root numbers (Ikram et al, 2019). The Trichoderma asperellum strain 6S-2 promoted the growth of apple seedlings in greenhouse, and also enhanced branch elongation of young apple trees (Wang et al, 2022).…”

Effect of Hydrogen Peroxide on the Soil Microbial Community Structure and Growth of Malus hupehensis Rehd. Seedlings under Replant Conditions

“…Bacillus not only inhibited the reproduction of pathogenic fungi, improved microbial community structure, and enhanced plant disease resistance but also secreted catabolic phytase to increase the amount of free phosphorus in the soil, promoted phosphorus uptake by plants, and improved the crop yield . Making fungi fertilizer from Trichoderma asperellum strain both promoted replanted seeding growth and development, optimized the soil microhabitats, and effectively alleviated ARD . In aquatic and terrestrial habitats, Lophiostom commonly occurs as sapwood on branches, stems, or bark in woody and herbaceous plants .…”

“… 59 Making fungi fertilizer from Trichoderma asperellum strain both promoted replanted seeding growth and development, optimized the soil microhabitats, and effectively alleviated ARD. 60 In aquatic and terrestrial habitats, Lophiostom commonly occurs as sapwood on branches, stems, or bark in woody and herbaceous plants. 61 Intaraudom et al 62 found that the secondary metabolites of Lophiostoma bipolare BCC25910 had no obvious inhibitory effect on disease-causing bacteria.…”

The effects of allelochemicals from root exudates of Flaveria bidentis on two Bacillus species

“…The experimental evidences in our systems suggest that the soil available nutrients and the nitrogen-fixing ability of B. megaterium increased with the increase in concentration of root exudates. Some studies have also demonstrated that the root exudates of Ageratina adenophora , maizes, and apple trees significantly increase the abundance of Bacillus in the soil and the soil available nitrogen ( Sun et al., 2021 ; Wang et al., 2021 ; Wang et al., 2022 ). The interactions among plant-microbes-nutrient may give positive feedback on the exotic plants ( Arafat et al., 2020 ).…”