Abstract
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing devastating vascular wilt disease of banana plants and has become a great concern threatening banana production worldwide. However, little information is known about the molecular mechanisms that govern the expression of virulence determinants of this important fungal pathogen. In this study, we showed that null mutation of three mitogen-activated protein (MAP) kinase genes, designated as FoSlt2, FoMkk2 and FoBck1, respectively, led to substantial attenuation in fungal virulence on banana plants. Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid. Biochemical analysis further confirmed the essential role of MAP kinases in modulating the production of fusaric acid, which was a crucial phytotoxin in accelerating development of Fusarium wilt symptoms in banana plants. Additionally, we found that the MAP kinase FoSlt2 was required for siderophore biosynthesis under iron-depletion conditions. Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2. Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.
Highlights
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing vascular wilt disease of banana plants, which is the most important lethal disease of banana leading to serious crop losses in banana plantations [1]
Considering the various role of Mitogen-activated protein (MAP) kinases in other fungal organisms, we set to search for the presence of their homologues in F. oxysporum f. sp. cubense (FOC) tropical race 4 strain XJZ2, which was isolated from diseased banana in Guangdong Province, China [2]
As the genome sequence of strain XJZ2 is not yet available, we firstly search the genome sequence of FOC tropical race 4 strain II5 using the coding sequences of the MAP kinase (MAPK) gene MGV1 of F. graminearum [10], the MAP kinase kinase (MAPKK) gene Mkk2 and the MAP kinase kinase kinase (MAPKKK) gene Bck1 from A. fumigatus [8] as query sequences
Summary
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing vascular wilt disease of banana plants ( called Panama disease), which is the most important lethal disease of banana leading to serious crop losses in banana plantations [1]. Cubense (FOC) is an important soil-borne fungal pathogen causing vascular wilt disease of banana plants ( called Panama disease), which is the most important lethal disease of banana leading to serious crop losses in banana plantations [1]. The pathogen invades, colonizes and blocks the xylem vessels of the roots, and disrupts water and nutrient translocation resulting in severe plant wilting [2]. Roles of MAP Kinases in F. oxysporum f. PLOS ONE | DOI:10.1371/journal.pone.0122634 April 7, 2015
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
