Effect of Low Temperature Stress on Physiological Characteristics and Differential Expression of Cold-related Genes of Loquat
The physiological changes and the expression of EjICE1 gene related to cold resistance embryos of two young loquat fruit under low temperature stress were studied to provide theoretical basis for the screening of new cold-resistant materials and the analysis of cold-resistant molecular mechanism of loquat.Using Dongting loquat(yellow-flesh)and its mutant type(white-flesh)that were growing in pots with fruits(DTM)as materials,the effects of simulated low temperature stress on the relative electrical conductivity,malondialdehyde(MDA)content,superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)activity and the expression of EjICE1 gene were studied.The results showed that the relative electrical conductivity(REC)of embryos of two young loquat fruits presented an'S'type curve change pattern,and the Logistic equation showed that the semi-lethal temperature of Dongting loquat and its mutant type was-4.759 and-2.811℃,respectively.The cold resistance of DTM was stronger than Dongting loquat.The SOD,POD and CAT activities of the two loquats and the MDA contents of Dongting loquat showed a trend of increasing first and then decreasing change pattern with the different time point of reaching the peak,while the MDA contents of Dongting loquat showed a slowly increased trend.SOD activity of Dongting loquat reached the peak at 1℃,and the content of MDA,POD,CAT activity reached peak at-1℃.The SOD,POD and CAT activity of DTM reached the peak at-3℃,while the content of MDA reached the peak at-5℃.The expression level of EjICE1 gene of DTM was higher than that of Dongting loquat at the same time.The expression of EjICE1 gene in DTM was the highest at-3℃,and that in Dongting loquat was the highest at-1℃.The expression level of EjICE1 gene was strongly inhibited in the two loquats under low temperature stress at-5℃.The cold resistance of DTM was stronger than Dongting loquat,under low temperature stress,DTM could rapidly activate higher protective enzyme activity and the expression of genes related to cold resistance,activate the low temperature response mechanism to resist and adapt to low temperature injury.
loquatlow temperature stresssemi-lethal temperaturephysiological characteristicsgene expression
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