Several Pestalotiopsis -like species cause gray blight disease in tea plants, resulting in severe tea production losses. However, systematic and comprehensive research on the diversity, geographical distribution, and pathogenicity of pathogenic species associated with tea plants in China is limited. In this study, 168 Pestalotiopsis -like isolates were obtained from diseased tea plant leaves from 13 primary tea-producing provinces and cities in China. Based on a multilocus (internal transcribed spacer, translation elongation factor 1-α, and β-tubulin gene region) phylogenetic analysis coupled with an assessment of conidial characteristics, 20 Neopestalotiopsis unclassified isolates, seven Pestalotiopsis species, including two novel ( Pestalotiopsis menhaiensis and Pestalotiopsis sichuanensis ), four known ( Pestalotiopsis camelliae , Pestalotiopsis chamaeropis , Pestalotiopsis kenyana , and Pestalotiopsis rhodomyrtus ) and one indistinguishable species, and three Pseudopestalotiopsis species, including two known ( Pseudopestalotiopsis camelliae-sinensis and Pseudopestalotiopsis chinensis ) and one indistinguishable species, were identified. This study is the first to evaluate Pestalotiopsis chamaeropis on tea plants in China. The geographical distribution and pathogenicity tests showed Pseudopestalotiopsis camelliae-sinensis to be the dominant cause of gray blight of tea plants in China. In vitro antifungal assays demonstrated that theobromine not only derepressed mycelial growth of the 29 representative isolates but also increased their growth. Correlation analysis revealed a linear positive relationship between the mycelial growth rate and pathogenicity ( P = 0.0148).
Huihui Yang,Ling Wang,Shengjie Li,Xingbiao Gao,Ningning Wu,Yifan Zhao,Weihong Sun
In the present study, the biocontrol efficacy of Metschnikowia pulcherrima E1 against grey spot rot ( Pestalotiopsis vismiae ) on loquat fruits was assessed and along with potential mechanisms of action. Results indicated that decay incidence and lesion diameter were both significantly reduced by treatment of fruits with the yeast, M. pulcherrima E1. M. pulcherrima E1 quickly colonized wounds in loquat fruit stored at either 20 °C or 4 °C. Scanning electron microscopy revealed that the yeast formed a biofilm on the wound surface in loquat fruit which inhibited the invasion of pathogenic fungi. M. pulcherrima E1 also competed with the pathogen for nutrients (iron) and space. Results of dual-culture petri dish assay indicated that M. pulcherrima E1 produces volatile antifungal compounds that inhibit the growth of P. vismiae. SPME-GC–MS analysis revealed that 3-methyl-1-butanol, phenylethyl alcohol and 1-Hexanol are the main volatile organic compounds produced by M. pulcherrima E1 and that had a significant inhibitory effect on the growth of fungal mycelia. M. pulcherrima E1 induced a higher level of defense-related enzyme activity in loquat fruit, including polyphenol oxidase, peroxidase, catalase, ascorbate peroxidase, and phenylalanine ammonia-lyase. Collectively, the results of the present study indicate that M. pulc herrima E1 has good potential to be used as a biocontrol agent against postharvest grey spot rot on loquats. The different mechanisms of action exhibited by M. pulcherrima E1 enhances its ability to control P. vismiae .
危险品化学品经营许可证（带存储）