Antifungal Activity and Possible Mode of Action of Ningnanmycin Against Tea Gray Blight Disease Pathogen Pseudopestalotiopsis camelliae-sinensis

Abstract

Gray blight disease is a serious disease of tea (Camellia sinensis (L.) Kuntz), for which there is currently no effective control or preventative measure apart from fungicides. Screening for effectiveness of a natural anti-microbial against this pathogen and identifying its mode of action could contribute to the management of this disease. Antifungal activity of the anti-microbial Ningnanmycin (NNM) from Streptomyces noursei var. xichangensis against the pathogen causing gray blight disease, Pseudopestalotiopsis camelliae-sinensis (F. Liu & L. Cai) strain GZHS-2017-010 was confirmed in vitro by the mycelial growth rate method. Optical microscopy, scanning electron microscopy and transmission electron microscopy were used to observe morphological change of hyphae of Ps. camelliae-sinensis treated with NNM. RNA sequencing, bioinformatics and quantitative real-time PCR were used to identify genes in the hyphae which were differentially expressed in response to treatment with NNM. Thirty-eight genes from sixteen pathways, known as targets of antifungal agents, were used to investigate gene expression in hyphae at the half-maximal effective concentration (EC50) dosage, EC30, and EC70 for 1, 7, or 14 h. The results indicated that NNM can inhibit the growth of hyphae in vitro, with an EC50 of 75.92 U/mL, inducing morphological changes in organelles, septa, and extracellular polysaccharides, targeting ribosomes to disturb translation in protein synthesis, and influencing some biosynthetic functions of the hyphae.

Inhibition Molecular Mechanism of the Novel Fungicidal N-(Naphthalen-1-yl) phenazine-1-carboxamide against Rhizoctonia solani

“…The raw data from processing groups 1, 2, and 3, and controls 1, 2, and 3 were sequenced. After removing the low-quality data, there were 22,582,425,26,800,753,20,692,153,25,126,831,19,678,982, and 20,868,689 clean reads, respectively. The percentages of the ratio of the Q20 (percentage of base mass greater than 20 to total base ratio) were 98.70%, 98.65%, 98.69%, 98.50%, 98.26%, and 98.91%.…”

“…The traditional rice sheath blight control agent jinggangmycin has been used for nearly 40 years, but its efficacy has displayed a downward trend. The EU classifies it as an antibiotic, and its future use will be increasingly restricted [19]. Therefore, developing novel, efficient, and low-risk fungicides for controlling rice sheath blight is paramount.…”

Potentiality of actinobacteria to combat against biotic and abiotic stresses in tea [Camellia sinensis (L) O. Kuntze]

“…xichangensis was studied for antifungal activity against the PPF causing grey blight disease, Pseudopestalotiopsis camelliae‐sinensis , a severe disease of tea. The results indicated that Ningnanmycin can inhibit the growth of fungal hyphae in vitro, by inducing morphological changes and extracellular polysaccharides; interfere with protein synthesis by targeting ribosomes involved in translation (Yang et al, 2021). An important antibiotic is azalomycin, belonging to macrolide group synthesized by Streptomyces malaysiensis MJM1968, and its prospective efficacy as a bio fungicide was tested using the culture filtrate extract to control Colletotrichum gloeosporioides , the causative agent of yam anthracnose (Cheng et al, 2010; Palaniyandi et al, 2016).…”

Development of a Cation Exchange SPE-HILIC-MS/MS Method for the Determination of Ningnanmycin Residues in Tea and Chrysanthemum

“…It has proven effective against rice bacterial blight pathogens and tobacco mosaic virus [ 1 ]. Recent studies have also shown that ningnanmycin could effectively prevent and treat tea leaf spot, making it a valuable antiviral and antifungal agent [ 2 ].…”