Quantification of SPS mRNA expression in banana fruit ripened under different conditions using real-time RT-PCR

Real-time reverse transcriptase (RT)-PCR using SYBR GreenI was applied to quantify sucrose phosphate synthase (SPS) mRNA expression at different storage days during the natural ripening (with no treatment), inhibited ripening with ethylene absorbent and accelerated ripening by treatment with propylene of banana fruit. The results showed that expression level of SPS mRNA were significantly different between 3 kinds of ripening fruit. Expression of SPS mRNA in fruit treated with propylene was dramatically promoted, the peak of SPS mRNA expression in these fruits appeared 16 days earlier than that in fruit with natural ripening. On the contrary, when fruit applied with ethylene absorbent, SPS mRNA expression was remarkably inhibited, the amount of SPS mRNA expression were significantly lower than that in naturally ripened fruit. These results indicated that the expression level of SPS mRNA of banana fruit can be impacted by regulating ethylene evolution, and that close relationships may exist between SPS mRNA expression and SPS activity, fruit softening, respiration rate, and ethylene production during ripening of banana fruit.