Post-transcriptional silencing of the SGE1 gene induced by a dsRNA hairpin in Fusarium oxysporum f. sp cubense, the causal agent of Panama disease

Abstract

ABSTRACT. Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin. Thirteen transformants were selected based on different morphological characteristics, and sporulation in these transformants was significantly reduced by approximately 95% (P < 0.05) compared to that of the wild-type strain. The relative SGE1 expression levels in the transformant strains were reduced by 27 to 47% compared to those in the wild-type strain. A pathogenicity analysis revealed that the transformants were able to reach the rhizomes and pseudostems of the inoculated banana plants. However, the transformants induced initial disease symptoms in the banana plants approximately 10 days later than that by the wild-type Foc, and initial disease symptoms persisted even at 45 days after inoculation. These results indicate that the SGE1 gene is directly involved in the virulence of Foc. Therefore, SGE1 may be a potential candidate for host-induced gene silencing in banana plants.

Current progress on pathogenicity‐related transcription factors in Fusarium oxysporum

“…Homologs of SGE1 in Foc tropical race 4 (Foc TR4) and race 1 are also required for regulation of virulence in banana roots. An in planta RNAi (siRNA) approach using host‐induced silencing of the SGE1 gene of Foc TR4 in banana plants confirmed that the SGE1 gene is directly involved in the virulence of Foc (Fernandes et al, 2016). In other Fusarium species, such as F. graminearum and F. verticillioides , Sge1 is thought to regulate the expression of effectors and secondary metabolite biosynthetic genes (Brown et al, 2014; Jonkers et al, 2012).…”

Transcription factor control of virulence in phytopathogenic fungi

“…In addition, conidiation was reduced and subsequent studies in the banana pathovar F. oxysporum f. sp. cubense through gene knockout and RNAi (Fernandes et al, 2016) identified similar regulatory roles for Sge1 in these contexts. For other members of the Fusarium genus, Gti1…”

“…oxysporum f. sp. cubense through gene knockout (Hou et al., 2018) and RNAi (Fernandes et al., 2016) identified similar regulatory roles for Sge1 in these contexts. For other members of the Fusarium genus, Gti1 orthologues are global regulators of effector gene expression or SM biosynthesis (Brown et al., 2014; Jonkers et al., 2012; Michielse et al., 2015).…”

Saffron-Fusarium oxysporum R1 dual transcriptomics unravels, defense mechanism of saffron and robust pathogenicity of Fusarium oxysporum R1

“…In Fusarium oxysporum f.sp. cubense tropical race 4 (Foc TR4) and race 1, Sge1 is required for virulence in banana roots (Fernandes et al 2016). In the present study, during Fox R1 infection, 11.4 log2Fold expression of gene encoding TF Sge1 was recorded.…”