MaHSFA1和MaHSP70在热处理诱导香蕉抗冷性中的作用

【目的】探讨MaHSFA1和MaHSP70基因在热处理诱导香蕉抗冷性中的作用,为有效延长香蕉贮运期提供参考依据。【方法】从香蕉基因组数据库(http://banana-genome.cirad.fr/)中搜索到MaHSFA1和MaHSP70基因序列,分别设计特异引物,利用实时荧光定量PCR(qRT-PCR)检测这2个基因在香蕉热处理和低温贮藏中的表达情况。【结果】MaHSFA1基因与其他物种的HSFA1基因同源性较低,仅在HSF DNA-bind区域的保守性很高;MaHSP70基因含有一个HSPA1-2,6-8-like NBD区域,且与其他物种的HSP70基因同源性很高。7℃冷藏诱导香蕉果实的MaHSFA1和MaHSP70基因表达量整体上呈下降趋势。经52℃热水处理诱导的MaHSFA1基因表达增强,且在热激处理后0.5 h有一个小高峰;在7℃低温贮藏过程中,经热处理后的MaHSFA1基因表达量在贮藏4.0 h时迅速升高至最大值,之后又迅速下降;MaHSP70基因表达量在热激处理后0.5 h迅速升高至最大值,约是对照处理(未经热激处理)的4倍,之后逐渐下降。在整个试验过程中除7℃贮藏120.0 h外,其他时段热激处理的MaHSFA1和MaHSP70基因表达量均高于对照处理。【结论】采后香蕉果实的抗冷性与MaHSFA1和MaHSP70基因表达增强密切相关,生产上可通过热处理提高香蕉果实的抗冷性,进而延长贮运期。

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

Objective]The 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. Method]The 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).Result]The 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. Conclusion]The 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.