Fajarudin Ahmad, Nani M. Martawi, Yuyu S. Poerba, Hans de Jong, Henk Schouten, Gert H. J. Kema

Theoretical and Applied Genetics, 25 August 2020 on-line

Abstract

Banana is an important fruit and food crop, but is threatened by Fusarium wilt, one of the most devastating soil-borne fungal diseases. Only host resistance facilitates banana cultivation in infested soils around the world, but the genetic basis of Fusarium wilt of banana (FWB) is unknown. We selfed a heterozygous wild banana accession Musa acuminata ssp. malaccensis (Mam, AA, 2n=22) to generate a mapping population and to investigate the inheritance of resistance to Race 1 and tropical race 4 (TR4) that cause FWB. Phenotyping (N=217) revealed segregation for resistance, and genotyping by sequencing resulted in 2802 high-quality single-nucleotide polymorphic markers (SNPs) that were used for genetic mapping. Combined analyses of these data showed that a single dominant resistance locus controls resistance to Race 1 and maps near the distal part of chromosome 10. Recombinants, together with the position of the putative resistance gene, were further analysed using graphical genotyping, which retrieved markers fanking a 360 kb genetic region that associates with Race 1 resistance. The region contains 165 putative genes on the reference genome, including 19 leucine-rich repeat receptor-like kinase-like genes. At the same position and phase, we also identifed a QTL for TR4 resistance, showing that the locus for resistance against Race 1 provided partial resistance to TR4. However, this efect was far less signifcant and hence not included in the mapping. These data support the breeding of new banana varieties with resistance to Fusarium wilt.

See https://doi.org/10.1007/s00122-020-03677-y

Figure 2:

Distribution of SNP markers across the 11 chromosomes according to their physical positions on the reference genome of Musa acuminata ssp. malaccensis (Mam) DH ‘Pahang’, version 2, released January 2016 (http://banana-genome-hub.southgreen.fr/ organism/Musa/acuminata). All chromosomes are covered by segregating markers, which means all chromosomes are heterozygous in the Mam parent that was self-pollinated in this study, thus allowing genetic mapping of all chromosomes in the segregating population.