Isolation and identification of Colletotrichum as fungal pathogen from tea and preliminary fungicide screening

Abstract

The increasing incidence of anthracnose disease in tea plant caused by Colletotrichum has become an important global concern. It is the cause of withered leaves of the tea plant, leading to a considerable decrease in the economic yield of tea, and thereby threatening the sustainable development of tea industries. In this study, Colletotrichum infected tea leaves were collected from three separate regions: Zhouning, Longyan, and Ningde in Fujian province, China. The pathogen was isolated from the leaves and identified based on morphology following Koch's postulates and DNA sequencing of the nuclear rDNA internal transcribed spacer (ITS) region, betatubulin 2 (β-Tub2), the large sub-unit of the nuclear ribosomal RNA gene (LSU), Glutamine synthetase (GS), and an oligonucleotide primer (CgInt). A total of six strains were identified with different cultural, morphological, and molecular characteristics. Furthermore, multi-locus phylogenetic analysis showed the six strains that belong to C.fructicola. Finally, a preliminary screening of nine chemical fungicides to inhibit the strain N by toxicity test identified 40% prochloraz at 0.1 μg mL-1 as the most effective method. The phylogenetic tree analysis revealed a close relationship between the identified strains, and the strains were classified based on cultural, morphological, and molecular characteristics. The findings of this study add to our understanding of C.fructicola, which will aid in the development of preventive measures, the improvement of tea quality, and the assurance of safe production.