The Quantitative Studing Of Several Wheat Related Mrinas In Drought Stress

Drought is an important adversity problem that global crops production faces. When plant Water Deficit, drought will threat its metabolism, which make plant produce reative oxygen species(ROS), demage cell membranes and inhibite plants photosynthesis. Therefore, studing the mechanism of wheat drought resistance have a profound significance.After drought stress, there are a series of signal systems in which many molecular components involve in wheat. Ca2+, ABA, IP3 are the second messengers in the signal of drought stress, then induce a series of coding protein and the uncoding protein gene expression, including effector molecules which directly involved in the biochemical response, regulator molecule and non-protein coding gene expression products. miRNAs are inducing products belonging to the non-protein coding gene expression products.MicroRNAs (miRNAs) are a kind of small fragments RNA of that are endogenous non- coding and have regulator function in recent years. Their size range from 19 to 25 nucleotides. They play regulator function in gene transcription level. The major function method of MiRNA is to assemble with other proteins for example AGO to form miRNA silencing inducing complex(miRISC), then binds to target mRNA. It regulates the expression of target gene by directly cleavaging target mRNA or inhibiting mRNA translation. The previous study about plant miRNA for example arabidopsis and rice have revealed that miRNAs play important roles in the physiological and biochemical processes, for example growth, development and adversity stresses(biological stress, abiotic stress) etc.In this study, we use 20% PEG6000 to simulate shanhe 6# which is the drought tolerance type and zhengyin 1# which is the drought sensitive type. We use the stem-loop RT-PCR and real-time quantitative PCR to appraise and verificate miRNA, then study the change of relevant miRNA expression in drought stress and the difference in different genotypes.Our study obtain these main conclusions:(1) Using 20% PEG6000 to simulate the two differece genotypes wheats,analysis the expression of miRNA TV21, miRNA PT12 and miRNA TV13 in laminas. The expression of miRNA TV21, miRNA PT12 upregulate along with increasement of stress time under drought stress. Therefore, we speculate that the two miRNA regulate target gene as a positive regulatory factor. The expression of miRNA TV13 are downregulated along with increasement of stress time under drought stress in laminas. We speculate that the two miRNA regulate target gene as a negative regulatory factor.(2) The three miRNA have expression specificity in two different genotypes of wheat. MiRNA TV21, miRNA PT12 and miRNA TV13 are more sensitive in zhengyin 1# than shanhe 6#.(3) MiRNA TV21, miRNA PT12 and miRNA TV13 have diferent responses time to the drought stress in different genotypes of wheat. Compared to wheat shanhe 6#, miRNA TV13 and miRNA PT12 response to the drought stress is more early in zhengyin 1# , and miRNA TV21 responses to the drought stress is more late in zhengyin 1# than shanhe 6#.(4) According to the difference of electrophoresis results between the Real-time quantitative PCR and Semi-quantitative PCR, we find that some factors influence the expression of miRNA TV21 and miRNA PT12, for example, drought stress, low temperature and metabolism.