Molecular Diagnosis and Vegetative Compatibility Group Analysis of Fusarium Wilt of Banana in Nepal

Fusarium wilt of banana (FWB), caused by Fusarium oxysporum f. sp. cubense (Foc), is the most important constraint of the banana industry globally. In Nepal, epidemics resembling FWB have been increasingly observed on the Malbhog cultivar in the past several years. However, the disease has not been officially reported yet, and consequently, little is known about the pathogen present across the country. In this study, we characterized 13 fungal strains isolated from banana plants of the Malbhog cultivar (Silk, AAB) showing symptoms similar to FWB in banana plantations in Nepal. All of the strains were typed as belonging to the F. oxysporum and caused FWB symptoms when inoculated in the Malbhog and Cachaco (Bluggoe, ABB) cultivars. No symptoms were observed in the Williams cultivar (Cavendish, AAA). Vegetative compatibility group (VCG) analysis classified the strains as VCG 0124 or VCG 0125. PCR analyses conducted with primers specific for Foc race 1 (Foc R1) or Foc tropical race 4 (TR4) revealed that all the strains reacted positively for Foc R1 and none for TR4. Altogether, our results demonstrated that the pathogen populations causing FWB of the Malbhog cultivar in Nepal were Foc R1. This work reported, for the first time, the occurrence of FWB in Nepal. Further studies with larger Foc populations are needed to better understand disease epidemiology to design sustainable disease management strategies.

[1]  L. Mostert,et al.  A Polyphasic Approach Reveals Novel Genotypes and Updates the Genetic Structure of the Banana Fusarium Wilt Pathogen , 2022, Microorganisms.

[2]  J. C. Rojas,et al.  First report of Fusarium oxysporum f. sp. cubense Tropical Race 4, causing Fusarium wilt in Cavendish bananas in Peru. , 2021, Plant disease.

[3]  Fusarium wilt of Banana, a Recurring Threat to Global Banana Production , 2021, Frontiers Research Topics.

[4]  M. Loganathan,et al.  First report of Fusarium oxysporum f.sp. cubense VCG 0125 and VCG 01220 of Race 1 infecting Cavendish bananas(Musa sp. AAA) in India. , 2020, Plant disease.

[5]  M. C. Mathews,et al.  First report of Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) causing banana wilt in the Island of Mayotte. , 2020, Plant disease.

[6]  M. Seidl,et al.  First Report of Fusarium Wilt Tropical Race 4 in Cavendish Bananas Caused by Fusarium odoratissimum in Colombia , 2020, Plant Disease.

[7]  Y. Duan,et al.  Identification of pathogenic groups and pathogenic molecular characterization of Fusarium oxysporum f. sp. sesami in China. , 2020, Phytopathology.

[8]  D. Turner,et al.  The Epidemiology of Fusarium Wilt of Banana , 2019, Front. Plant Sci..

[9]  A. Molina,et al.  First detection of Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) on Cavendish banana in India , 2019, European Journal of Plant Pathology.

[10]  S. Rajan,et al.  First Report of Fusarium Wilt in Banana Caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 in India , 2019, Plant Disease.

[11]  Michael F. Seidl,et al.  New Geographical Insights of the Latest Expansion of Fusarium oxysporum f.sp. cubense Tropical Race 4 Into the Greater Mekong Subregion , 2018, Front. Plant Sci..

[12]  T. Dubois,et al.  Genetic Diversity of Fusarium oxysporum f. sp. cubense in East and Central Africa. , 2018, Plant disease.

[13]  Michael F. Seidl,et al.  Worse Comes to Worst: Bananas and Panama Disease—When Plant and Pathogen Clones Meet , 2015, PLoS pathogens.

[14]  R. Ploetz.  Management of Fusarium wilt of banana: A review with special reference to tropical race 4 , 2015 .

[15]  T. Ganapathi,et al.  Fusarium wilt of banana: biology, epidemiology and management , 2015 .

[16]  M. Zander,et al.  Sequence variation in the putative effector gene SIX8 facilitates molecular differentiation of Fusarium oxysporum f. sp. cubense , 2014 .

[17]  Koichiro Tamura,et al.  MEGA6: Molecular Evolutionary Genetics Analysis version 6.0. , 2013, Molecular biology and evolution.

[18]  S. Zhong,et al.  Identification and application of a unique genetic locus in diagnosis of Fusarium oxysporum f. sp. cubense tropical race 4 , 2013 .

[19]  Jiang Zi-de.  Rapid Detection and Identification of Fusarium oxysporum f. sp. cubense Race 1 and Race 4 , 2012 .

[20]  R. Thangavelu,et al.  First Report on the Occurrence of a Virulent Strain of Fusarium Wilt Pathogen (Race-1) Infecting Cavendish (AAA) Group of Bananas in India. , 2010, Plant disease.

[21]  Manoel T. Souza,et al.  A molecular diagnostic for tropical race 4 of the banana , 2010 .

[22]  E. Steenkamp,et al.  Evolutionary Relationships among the Fusarium oxysporum f. sp. cubense Vegetative Compatibility Groups , 2009, Applied and Environmental Microbiology.

[23]  R. Ploetz,et al.  Multiple evolutionary origins of the fungus causing Panama disease of banana: concordant evidence from nuclear and mitochondrial gene genealogies. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[24]  J. Correll.  Nitrate nonutilizing mutants of Fusarium oxysporum and their use in vegetative compatibility tests , 1987 .

[25]  J. E. Puhalla.  Classification of strains of Fusarium oxysporum on the basis of vegetative compatibility. , 1985 .