miR395abcd与其靶基因ATRX在不同耐寒木薯品种中对低温响应的差异性分析

The Differential Analysis of mi R395abcd and Its Target Gene ATRX Response to Low Temperature in Different Cold Tolerance Cassava Varieties

通过实时定量PCR方法分析了mi R395abcd与其靶基因ATRX在两个木薯品种的4种低温处理下的差异表达情况,靶基因的定量引物设计在与mi RNA结合区的上游、结合边缘、结合区3个位置。结果显示mi R395abcd与其靶基因在两个木薯品种、4种低温处理和3个靶基因引物位置的表达量均不同,且mi R395abcd在C4和SC124两个品种间4种低温处理的6组两两比较中的相对表达量呈现完美的反向关系。进一步比较发现mi R395abcd与靶基因的负相关性在C4中最好,尤其是位于mi RNA与m RNA结合区上游的a引物的消长关系在AH(驯化后寒害:25~14℃驯化5 d后再降至4℃)和NAH(非驯化寒害:25℃直接降至4℃)中表现得最典型。具体而言,mi R395abcd在C4的AH和NAH处理中上调而在SC124的AH和NAH处理中下调表达,前期表型分析中AH和NAH处理下C4的低温胁迫症状小于SC124,预示着mi R395abcd的上调表达有利于木薯减轻低温伤害,其表达差异能够表征C4和SC124在耐低温性能的表型差异,且mi R395abcd对其靶基因ATRX的调控在木薯低温响应过程中起着正向保护作用。

By using of the real-time quantitative polymerase chain reaction(q PCR) technique, we analyzed the differential expression of mi R395 abcd and its target gene ATRX in two cassava varieties under 4 low temperature treatments. Quantitative primers of target gene were designed with three primers base-paired to the upstream, the edge and internal region which matching with the mi RNA. The results showed that the expression level of mi R395 abcd and its target gene ATRX differed among the two cassava varieties, four chilling treatments and 3primers base-paired with different positions of same target gene, and the relative expression of mi R395 abcd exhibited perfect contrary relationship between C4 and SC124 in six pairwise comparisons under four low temperature treatments. Further, the negative correlation between mi R395 abcd and ATRX target gene was most typical in C4, especially in the primer a which matched upon the upstream of mi RNA: m RNA matchinng region under the AH(cold injury after acclimation: after five days acclimation from 25℃ to 14℃, and then dropped to 4℃)and NAH(non-acclimation cold injury: directly dropped from 25℃ to 4℃) treatments. Specifically, mi R395 abcd was up-regulated in C4 while down-regulated in SC124 under AH and NAH treatments, and symptom of low temperature stress of C4 was lower than SC124 under AH and NAH in prophase phenotype analysis. It indicated that up-regulation of mi R395 abcd was in favour of cassava reducing cold damage, and the expression differences of mi R395 abcd could characterize the phenotypic differences of C4 and SC124 subjected to low temperature treatments, and the regulations of mi R395 abcd on ATRX played positive protection roles in cassava low temperature responses.