Heart rot disease poses a severe threat to the health of Abies georgei var. smithii forests in southeastern Xizang. This study aimed at identifying the causal pathogen and screening highly antagonistic Trichoderma strains as well as evaluating their antifungal activity to provide potential biocontrol resources for managing this disease. The pathogen was identified through tissue isolation, morphology observation and molecular phylogenetic analysis. Antagonistic Trichoderma strains were initially screened using the dual-culture assay, and their inhibitory activity was further evaluated by assessing both volatile metabolites (via the two-sealed-base- plates method) and non-volatile metabolites (via the solid dilution method with sterile culture filtrates). Results indicated that the dominant pathogen infecting living A. georgei var. smithii trees was Fomitopsis subpinicola. In total, 36 Trichoderma strains were isolated, among which strain M28 exhibited the strongest inhibition in the dual-culture assay. Assessment of volatile metabolites revealed that Trichoderma afroharzianum M28 had the highest inhibitory effect, and T. atroviride M49 was in the next place. Tests with sterile culture filtrates demonstrated that filtrates of all seven selected Trichoderma strains inhibited the pathogen’s growth at different tested concentrations. The filtrate of T. atroviride M49 exhibited the strongest inhibitory activity at concentrations of 25% and 33%. This study confirms F. subpinicola as the causal agent of heartwood brown rot in A. georgei var. smithii in southeastern Xizang, and highly antagonistic Trichoderma strains M49 and M28 are excellent candidates of biological control agents.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |