Isolation and Identification of Trichoderma asperellum , the Novel Causal Agent of Green Mold Disease in Sweetpotato

Postharvest disease is an important limiting factor for sweetpotato production. Recently, a new green mold disease was found in sweetpotato storage roots. To investigate the mechanism underlying the pathogenesis of the disease, the pathogen was isolated and identified based on morphological and molecular features, and its characteristics were further analyzed by pathogenic and antagonistic evaluations. The results showed that the isolated pathogen (CRI-Ta1) was identified as based on the similar growth and morphological features with spp., 99% homology of internal transcribed spacer (ITS) sequence, and membership to the same phylogenetic group with the model strain of (CBS 433.97). The pathogenic analysis revealed that CRI-Ta1 could cause green mold disease through wound infection on the storage roots and the strains reisolated from infected storage roots could cause disease in different sweetpotato varieties, which was fulfilled in Koch's postulate. Moreover, CRI-Ta1 could also infect other common crop species, including chestnut, carrot, apple, pear, and others. It indicated that CRI-Ta1 was the pathogen to the storage roots of sweetpotato and had a wide host range. Additionally, in vitro antagonistic evaluation showed that CRI-Ta1 effectively inhibited the growth of common sweetpotato pathogens, including and . However, further research is needed on the potential of CRI-Ta1 to control sweetpotato diseases in vivo. Collectively, our findings provided valuable insights into the characteristics of the CRI-Ta1 in sweetpotato and would be helpful to the prevention and control of sweetpotato green mold disease.