The genome and transcriptome of Musa itinerans unveil novel candidate genes for fusaric acid resistance

Fusarium wilt by Fusarium oxysporum f. sp. cubense, especially the tropical race 4 (Foc-TR4), caused severe losses of worldwide banana. A critical toxin produced by Foc-TR4 is the fusaric acid (FA), yet few studies have investigated the source of potential resistance. We identified the FA-resistant wild banana Musa itinerans var. formosana and assembled the chromosome-level genome. Our fully factorial transcriptome analyses showed that genes upregulated in the susceptible M. acuminata AAA Cavendish "Pei-Chiao" are associated with the downstream response after FA impact, while those upregulated in the resistant M. itinerans are involved in the membrane system and endocytosis, potentially reflecting the upstream reaction to repair FA damage to the membrane. Through a novel analysis taking the gene expression plasticity response into account, we identified a strong candidate gene, eEF1A, the only gene with consistent expression upregulation in the resistant species M. itinerans upon FA treatment at all time points. While generally regarded as a housekeeping gene, eEF1A shows FA resistance effects when overexpressed in tobacco leaves. The results unveil novel candidate genes of FA resistance that have not been reported in banana species and propose a unique direction for future engineering of banana varieties.