Pear trees have a long history of cultivation in China and are valued for their medicinal and nutritional properties. However, in recent years, pear tree rot disease has become increasingly severe, emerging as a primary limiting factor affecting the lifespan, yield, and quality of pear trees. On April 17, Professor He Yujian's team from the Future Technology Institute at the University of Chinese Academy of Sciences published a paper in the international academic journal Frontiers in Microbiology detailing the biological control of pear tree rot disease. They reported the discovery of a strain of biocontrol fungus, Trichoderma virens, selected from the wild, which exhibits excellent antagonistic effects against the pathogens causing pear tree rot disease, and explored the related mechanisms of fungal inhibition.
Pear tree rot disease is mainly divided into ulcerative (wet rot) and twig blight (dry rot) types, and it is the most common and destructive disease affecting pear trees. This disease occurs worldwide, with notable impacts on famous Chinese pear varieties such as Hongxia pear and Korla fragrant pear from Xinjiang, resulting in significant reductions in yield and quality.
Previous research has indicated that pear tree rot disease is caused by the fungus Valsa pyri, and current orchard practices such as lesion removal and chemical fungicides have some control effects. However, due to the invasion of the pathogen into the cambium and xylem of pear trees, along with broader ecological factors, the disease is challenging to control effectively. Affected branches often decline, requiring pruning, ultimately leading to the eventual abandonment of the tree. Thus, finding a comprehensive solution for pear tree rot disease has remained an industry challenge.
In this study, Professor He Yujian's team found that the culture filtrate of Trichoderma virens could disrupt the mycelial membrane of the pathogens causing pear tree rot disease, effectively inhibiting their growth. Under laboratory conditions, the biocontrol efficiency against pear tree rot disease reached 73.5%. Further research revealed that the culture filtrate of Trichoderma virens significantly downregulated the expression of antioxidant system-related genes in the pathogens causing pear tree rot disease, and inhibited the activities of catalase and superoxide dismutase enzymes, leading to the accumulation of reactive oxygen species in the fungal hyphae, causing cellular damage or death. Additionally, LC-MS analysis identified artemisinin ester as one of the active components in the culture filtrate of Trichoderma virens, with this strain preserved at the China General Microbiological Culture Collection Center (CGMCC No.40848).
This research provides scientific evidence for the biological control of pear tree rot disease, offering a comprehensive solution to this industry challenge. Combined with Professor He Yujian's team's soil remediation and improvement techniques, field trials conducted in over 500 acres of Hongxia pear orchards in Huairou, Beijing, demonstrated significant restoration of pear tree health within the year, with yields, quality, and flavor returning to normal levels.
This research was supported by the National Natural Science Foundation of China and the government of Huaibei Town, Huairou District, Beijing. Zhang Yang, a doctoral student at the University of Chinese Academy of Sciences, is the first author of the paper, with He Yujian and Associate Professor Wu Li from the University of Chinese Academy of Sciences serving as corresponding authors.
Related Paper Information: https://doi.org/10.3389/fmicb.2024.1377683
The screened green mold fungus (CGMCC No.40848) exhibits significant control effects against pear tree rot disease. Image source: Frontiers in Microbiology.
