Genome and Transcriptome Analysis of the Fungal Pathogen Fusarium oxysporum f. sp. cubense Causing Banana Vascular Wilt Disease

Abstract

BackgroundThe asexual fungus Fusarium oxysporum f. sp. cubense (Foc) causing vascular wilt disease is one of the most devastating pathogens of banana (Musa spp.). To understand the molecular underpinning of pathogenicity in Foc, the genomes and transcriptomes of two Foc isolates were sequenced.Methodology/Principal FindingsGenome analysis revealed that the genome structures of race 1 and race 4 isolates were highly syntenic with those of F. oxysporum f. sp. lycopersici strain Fol4287. A large number of putative virulence associated genes were identified in both Foc genomes, including genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions. Importantly, relative to the Foc race 1 isolate (Foc1), the Foc race 4 isolate (Foc4) has evolved with some expanded gene families of transporters and transcription factors for transport of toxins and nutrients that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana. Transcriptome analysis disclosed a significant difference in transcriptional responses between Foc1 and Foc4 at 48 h post inoculation to the banana ‘Brazil’ in comparison with the vegetative growth stage. Of particular note, more virulence-associated genes were up regulated in Foc4 than in Foc1. Several signaling pathways like the mitogen-activated protein kinase Fmk1 mediated invasion growth pathway, the FGA1-mediated G protein signaling pathway and a pathogenicity associated two-component system were activated in Foc4 rather than in Foc1. Together, these differences in gene content and transcription response between Foc1 and Foc4 might account for variation in their virulence during infection of the banana variety ‘Brazil’.Conclusions/SignificanceFoc genome sequences will facilitate us to identify pathogenicity mechanism involved in the banana vascular wilt disease development. These will thus advance us develop effective methods for managing the banana vascular wilt disease, including improvement of disease resistance in banana.

Functional analysis of the G-protein α subunits FGA1 and FGA3 in the banana pathogen Fusarium oxysporum f. sp. cubense

“…Until now, the molecular pathogenicity mechanism of Foc was not well understood. The whole genome sequence analysis of this fungus revealed a large number of putative virulence associated genes, including Ga genes and a Gb gene [14]. The functional analysis of the Ga s subunit FGA2 and the Gb subunit FGB1 in Foc have been completed and covered separately [15].…”

In-Silico Identification of Novel Resistant Genes for Fungal Pathogen Fusarium oxysporum f. sp. cubense Race 4: Causative Agent of Banana Vascular Wilt Disease

“…The information about the pathogenic SIX1a, SIX1b, SIX1c, SIX2 and SIX8 proteins of the fungus were obtained through literature [21].…”

Transcriptome Analysis in Banana

“…Sequencing of the genomes and transcriptomes of two Fusarium oxysporum f. sp. cubense (Foc) isolates, the pathogens of banana that causes vascular wilt disease lead to the identification of genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions and more importantly transporters and transcription factors for toxins and nutrients transport that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana [14]. The transcriptome analysis of the banana fruit during the ripening process revealed the underlying mechanism of ripening and also to the identification of a large number of novel differentially regulated genes associated with cell wall degradation and synthesis of aromatic volatiles [15].…”

“…Its application in Musa could improve our understanding of the molecular mechanisms involved in defence [14], biosynthesis, and other biochemical processes [12,13,15] providing a potential resource for future genetic or genomic studies on this important food crop. It can also be expected to bridge a critical gap that exists in the Musa comparative genomics and could ultimately contribute to the evolutionary and functional studies of its genes and genomes.…”