Fusarium graminearum ATP-Binding Cassette Transporter Gene FgABCC9 Is Required for Its Transportation of Salicylic Acid, Fungicide Resistance, Mycelial Growth and Pathogenicity towards Wheat

Abstract

ATP-binding cassette (ABC) transporters hydrolyze ATP to transport a wide range of substrates. Fusarium graminearum is a major causal agent of Fusarium head blight, which is a severe disease in wheat worldwide. FgABCC9 (FG05_07325) encodes an ABC-C (ABC transporter family C) transporter in F. graminearum, which was highly expressed during the infection in wheat and was up-regulated by the plant defense hormone salicylic acid (SA) and the fungicide tebuconazole. The predicted tertiary structure of the FgABCC9 protein was consistent with the schematic of the ABC exporter. Deletion of FgABCC9 resulted in decreased mycelial growth, increased sensitivity to SA and tebuconazole, reduced accumulation of deoxynivalenol (DON), and less pathogenicity towards wheat. Re-introduction of a functional FgABCC9 gene into ΔFgABCC9 recovered the phenotypes of the wild type strain. Transgenic expression of FgABCC9 in Arabidopsis thaliana increased the accumulation of SA in its leaves without activating SA signaling, which suggests that FgABCC9 functions as an SA exporter. Taken together, FgABCC9 encodes an ABC exporter, which is critical for fungal exportation of SA, response to tebuconazole, mycelial growth, and pathogenicity towards wheat.

Pyocyanin, a Metabolite of Pseudomonas Aeruginosa, Exhibits Antifungal Drug Activity Through Inhibition of a Pleiotropic Drug Resistance Subfamily FgABC3

“…A possible mechanism has been suggested by Kerr et al, (1999) that involves a reduction in camp in hyphae formation [36]. The treatment with pyocyanin resulted also in a decrease in the secretion of the B-trichothecenes mycotoxins, Deoxynivalenol (DON) and Nivalenol (NIV) by the fungi, re- flecting the protective role of pyocyanin on wheat plant against infections which is comparable to the study done by [15].…”

“…graminearum has 62 ABC transporter genes, which are divided into seven families (A-G) according to domain architecture and phylogenetic data [14]. FgABC9, an ABC-C transporter gene with an MRP domain, is involved in the export of salicylic acid by F. graminearum and in the fungal response to tebuconazole and pathogenesis in wheat [15]. Qi PF et al, (2018) have shown that the deletion of FgAB-CC9 led to a decrease in mycelial growth, a reduction in the accumulation of deoxynivalenol (DON), and consequently to a less pathogenicity towards wheat [15].…”

“…FgABC9, an ABC-C transporter gene with an MRP domain, is involved in the export of salicylic acid by F. graminearum and in the fungal response to tebuconazole and pathogenesis in wheat [15]. Qi PF et al, (2018) have shown that the deletion of FgAB-CC9 led to a decrease in mycelial growth, a reduction in the accumulation of deoxynivalenol (DON), and consequently to a less pathogenicity towards wheat [15]. Another study reported that the deletion of other FgABC transporters, FgABC3 and FgABC4, enhanced sensitivity to several SBI class I fungicides [16].…”

“…Test organisms, gram-negative bacteria P. aeruginosa, and the fungus F. graminearum, were obtained from [15,21]. These organisms were obtained from Rahme LG et al, (1995) and the school of Agriculture and maintained at the Lebanese University on nutrient agar slants at 4 °C until use.…”

Pathogenicity and Virulence Factors of Fusarium graminearum Including Factors Discovered Using Next Generation Sequencing Technologies and Proteomics

“…Many studies have indicated the roles of multiple ATP-binding cassette transporters or major facilitator superfamily (MFS) proteins in virulence activities of the fungi such as Botrytis cinerea, Cochliobolus carbonum, Cercospora kikuchii, Fusaria, Magnaporthe grisea, Mycosphaerella graminicola and Penicillium digitatum [83][84][85][86][87][88][89][90][91][92]. The same applies to F. graminearum, ATP-Binding Cassette Transporter Gene FgABCC9 was found to be involved in the fungus's pathogenicity towards wheat [93]. F. graminearum attacks its host plant through the secretion of mycotoxins characterized as virulence factors.…”