Role of MaHSFA1 and MaHSP70 in heat-induced chilling tolerance of banana fruit

ObjectiveThe present experiment was conducted to investigate role of MaHSFA1 and MaHSP70 genes in heat-induced chilling tolerance of banana, in order to provide reference for prolong period of storage and transportation of bananas. MethodThe sequences of MaHSFA1 and MaHSP70 genes were searched from the banana genome database (http://banana-genome.cirad.fr/), and two pairs of specific primers were designed. Then, the expression of MaHSFA1 and MaH-SP70 genes in heat treatment and cold storage of banana fruit was analyzed using quantitative real-time PCR(qRT-PCR).ResultThe results showed that, the MaHSFA1 gene shared low homology with HSFA1s gene of other species, and only its HSF DNA-bind domain was highly conserved. The MaHSP70 gene contained a HSPA1-2,6-8-like NBD domain, and shared high homology with HSP70 gene of other species. As a whole, the cold storage(7 ℃) decreased gradually expres-sion of MaHSFA1 and MaHSP70 genes in banana fruit. The gene expression of MaHSFA1 were increased by heat-water treatment(52℃), and reached peak at 0.5 h after heat treatment. When banana fruit was stored at 7 ℃, the gene expres-sion of MaHSFA1 gene increased rapidly to the maximum in heat-treated fruit at 4.0 h, and then rapidly declined. In addi-tion, the expression of MaHSP70 gene increased rapidly to the maximum at 0.5 h after heat treatment, and was four times that of control, and then rapidly declined. In the whole treatment process, the expression of MaHSFA1 and MaHSP70 genes in heat-treated fruits were higher than that of control(non-heated fruits) at other times. ConclusionThe chilling tolerance of postharvest banana fruit may be closely related to high expression level of MaHSFA1 and MaHSP70 genes. Heat treatment can induce chilling tolerance of banana fruit in production and prolong period of storage and transportation of bananas.