Oral Presentation Science Protecting Plant Health 2017

Genetic dissection of Foc resistance using Musa acuminata ssp. malaccensis (4382)

Andrew Chen 1 , Jessica D Morgan 1 , Sam Fraser-Smith 1 , Manual Zander 1 , Pradeep Ruperao 2 , Jacqueline Batley 2 , Sharon Hamill 3 , David Edwards 2 , Elizabeth Aitken 1
  1. School of Agriculture and Food Science, University of Queensland, St Lucia, QLD, Australia
  2. School of Plant Biology, University of Western Australia, Perth, WA, Australia
  3. Department of Agriculture, Fisheries and Forestry, Maroochy Research Station, Nambour, QLD, Australia

Fusarium wilt is one of the major diseases threatening banana production worldwide. The causal agent is the soil-borne fungus Fusarium oxysporum sp. cubense (Foc) which enters the roots and then colonises the vascular tissues to induce a lethal wilt. We have identified Foc resistance in the wild banana Musa acuminata subsp malaccensis. F2 progeny testing showed segregation of a single dominant gene conferring resistance to race 1, sub-tropical race 4 and tropical race 4. Genotyping-By-Sequencing was performed on resistant and susceptible progeny to identify SNPs on a genome-wide scale. A strong level of association between SNP zygosity and resistance was identified in a region on chromosome 3. Using SNP based markers, this region was fine-mapped. The QTL was delimited to a 157 kb physical sequence containing 28 putative candidate genes. Only 15 genes are predicted to carry non-synonymous SNPs leading to changes in the encoded amino acid sequence. Analysis of the expression profiles of these candidates are underway using Foc infected roots of resistant and susceptible plants. Transcriptional changes will be correlated with resistance. SNPs from gene markers co-segregating with the resistance locus are currently being validated for the detection of the resistance allele in other diploid banana genotypes. Identifying the gene underpinning resistance will help to understand better the mechanisms of resistance at the molecular level. The molecular markers closely linked to resistance will be useful tools in marker-assisted breeding programs.