Characteristics of Epicoccum latusicollum as revealed by genomic and metabolic phenomic analysis, the causal agent of tobacco Epicoccus leaf spot

Front Plant Sci. 2023 Aug 24:14:1199956. doi: 10.3389/fpls.2023.1199956. eCollection 2023.

Abstract

Epicoccum latusicollum is a fungus that causes a severe foliar disease on flue-cured tobacco in southwest China, resulting in significant losses in tobacco yield and quality. To better understand the organism, researchers investigated its optimal growth conditions and metabolic versatility using a combination of traditional methods and the Biolog Phenotype MicroArray technique. The study found that E. latusicollum exhibited impressive metabolic versatility, being able to metabolize a majority of carbon, nitrogen, sulfur, and phosphorus sources tested, as well as adapt to different environmental conditions, including broad pH ranges and various osmolytes. The optimal medium for mycelial growth was alkyl ester agar medium, while oatmeal agar medium was optimal for sporulation, and the optimum temperature for mycelial growth was 25°C. The lethal temperature was 40°C. The study also identified arbutin and amygdalin as optimal carbon sources and Ala-Asp and Ala-Glu as optimal nitrogen sources for E. latusicollum. Furthermore, the genome of E. latusicollum strain T41 was sequenced using Illumina HiSeq and Pacific Biosciences technologies, with 10,821 genes predicted using Nonredundant, Gene Ontology, Clusters of Orthologous Groups, Kyoto Encyclopedia of Genes and Genomes, and SWISS-PROT databases. Analysis of the metabolic functions of phyllosphere microorganisms on diseased tobacco leaves affected by E. latusicollum using the Biolog Eco microplate revealed an inability to efficiently metabolize a total of 29 carbon sources, with only tween 40 showing some metabolizing ability. The study provides new insights into the structure and function of phyllosphere microbiota and highlights important challenges for future research, as well as a theoretical basis for the integrated control and breeding for disease resistance of tobacco Epicoccus leaf spot. This information can be useful in developing new strategies for disease control and management, as well as enhancing crop productivity and quality.

Keywords: Biolog Phenotype MicroArray; Epicoccum latusicollum; biological characteristics; flue-cured tobacco; whole genome sequence.

Grants and funding

This work was supported by the China National Tobacco Corporation (110202101048(LS-08), 110202001035(LS-04)), the National Natural Science Foundation of China (31960550, 32160522), the Hundred Level Innovative Talent Foundation of Guizhou Province [GCC(2022)028-1], the Guizhou Science Technology Foundation (ZK[2021]Key036), the International Science and Technology Cooperation Base ([2020]4102), Guizhou Provincial Academician Workstation of Microbiology and Health ([2020]4004), and the Guizhou Tobacco Company (2020XM22, 2020XM03). This work was also funded by the Guizhou Province Applied Technology Research and Development Funding Post-subsidy Project. The authors declare that this study received funding from the China National Tobacco Corporation and Guizhou Tobacco Company. The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.