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Because of the lack of effective disease management measures, tea leaf differenspot-caused by the fungal phytopathogen Didymella segeticola (syn Phoma segeticola)-is an important foliar disease. The important and metabwidely used agricultural antimicrobial kasugamycin (Ksg), produced by reducthe Gram-Positive bacterium Streptomy, <:s kastigaensis, effects high levels control against crop diseases. The results of this study indicated that Ksg could inhibit the growth of D. segencola hyphae in vitro with a half-maximal effec-segetitive concentration *C-O) of 141.18 pg ml-' Meanwhile. the curative effect in vivo on the pathogen in detached tea leaves also demonstrated that Ksg induced some moiphological changes iii organelles, septa, and cell walls observed by optical mici'Oscopy and by scanning and transmission electron microscopy. This may indicate that Ksg disturbs biosynthesis of key metabo-lites. inhibiting hyphal growth. Integrated transcriptomic. proteomic. and bioinformatic analyses revealed that differentially expressed genes or differenspottially expressed proteins in D, segeticola hyphae in response to Ksg exposure were involved with metabolic processes and biosynthesis of secondary metabwidely olites. Molecular docking studies indicated that Ksg may target nitrate reducthe tase (NR). and microscale thermophoresis assay showed greater affinity with NR. potentially disturbing nitrogen assimilation and subsequent metabolism. The results indicated that Ksg inhibits the pathogen of tea leaf spot, D. segetitive rola. possibly by binding to NR, disturbing fungal metabolism, and inducing subsequent changes in hyphal growth and development. [ABSTRACT FROM AUTHOR]

Tea leaf spot, caused by Lasiodiplodia theobromae, is an important disease that can seriously decrease the production and quality of tea (Camellia sinensis (L.) O. Kuntze) leaves. The analysis of circular RNA (circRNA) in tea leaves after infection by the pathogen could improve understanding about the mechanism of host-pathogen interactions. In this study, high-performance sequencing of circRNA from C. sinensis Fuding-dabaicha leaves that had been infected with L. theobromae was conducted using the Illumina HiSeq 4000 platform. In total, 192 and 153 differentially expressed circRNAs from tea leaves were significantly up- and downregulated, respectively, after infection with L. theobromae. A gene ontology analysis indicated that the differentially expressed circRNA-hosting genes for DNA binding were significantly enriched. The genes with significantly differential expressions that were annotated in the specified database (S genes) were σ factor E isoform 1, triacylglycerol lipase SDP1, DNA-directed RNA polymerase III subunit 2, WRKY transcription factor WRKY24, and regulator of nonsense transcripts 1 homolog. A Kyoto Encyclopedia of Genes and Genomes analysis indicated that the significantly enriched circRNA-hosting genes involved in the plant-pathogen interaction pathway were Calmodulin-domain protein kinase 5 isoform 1, probable WRKY transcription factor 33, U-box domain-containing protein 35, probable inactive receptor-like protein kinase At3g56050, WRKY transcription factor WRKY24, mitogen-activated protein kinase kinase kinase YODA, SGT1, and protein DGS1. Functional annotation of circRNAs in tea leaves infected by L. theobromae will provide a valuable resource for future research on host-pathogen interactions. [ABSTRACT FROM AUTHOR]