低夜温下番茄ABA缺失突变体和野生型叶片中miRNA差异表达分析

为揭示番茄叶片中miRNA对非生物胁迫的响应机制，以番茄ABA缺失突变体sit和野生型番茄RR为试验材料。采用实时荧光定量（qRT-PCR）技术检测叶片中6个miRNA（miR160、miR162、miR166、miR1919、miR397和miR6026）及其预测的靶基因在夜间低温和喷施外源ABA逆境胁迫下的表达情况。结果表明，在15 ℃夜温（对照）下，sit的ABA含量是60 ng · g^-1，RR是120 ng · g^-1，sit叶片的保卫细胞和气孔的开度都明显大于野生型RR，ABA缺失突变体sit中miRNA的表达量与野生型RR相比都显著下调，其靶基因除miR1919外，表达量都上调；夜间低温（6 ℃）处理12 h后，所有miRNA在sit中比RR中的表达量都显著增加；喷施80 mg · L^-1的ABA后，sit中miR162、miR166、miR1919及miR397比0 mg · L^-1 ABA处理的表达量显著上调。推测miR160、miR162和miR6026通过依赖ABA信号途径参与夜间低温胁迫。

The Effect of Low Night Temperature on miRNA Expression in Mutant and Wild Type Tomato Leaf

Wild type RR and ABA deletion mutant（sit）were used to elucidate the mechanism by which miRNAs response to abiotic stress mechanism in tomato（Lycopersicon esculentum L.）leaf. The expression of 6 miRNAs（miR160，miR162，miR166，miR1919，miR397 and miR6026）and their target mRNAs were investigated by quantitative real-time PCR（qRT-PCR）technology. The results show that under 15 ℃（night temperature），the ABA content of sit and RR were 60 ng · g^-1 and 120 ng · g^-1 respectively，while the opening of guard cells and stomata of sit were significantly greater than RR. The expression of all miRNAs decreased in sit plants compared to those of the RR plants treatment. And all their target mRNAs up-regulated other than miR1919. All miRNAs expression in sit increased significantly after 12 h（6 ℃）. When the sit was sprayedwith 80 mg · L^-1 ABA，the expressions of miR162，miR166，miR1919 and miR397 were significantly higher than that with 0 mg · L^-1 ABA. These results suggested that miR160，miR162 and miR6026 play an important role in response to low night temperature stress by ABA-dependent signal pathway.