Abstract:

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.

Key words: tomato, low night temperature, exogenous ABA, miRNA