The Exploration Of MiRNA408 In Arabidopsis And Rice Photosynthetic Function And Antioxidant System Under The UV-B Radiation Stress

Rice is the main agricultural crops of supply of the world's population,but it is also one of the model plant in biology science research?In recent years,UV-B radiation enhanced was caused by the thinning ozone layer in order that this made the output of grain crops to greatly reduced,become one of the focus of global attention.Moreover,plant photosynthesis,antioxidant system and the DNA will be affected under the UV-B radiation enhancement.Previous studies have found that the expression of miR408 in European populus tomentosa was increased,miR408 in rice and European populus tomentosa is extremely high,So,we have made miR408 precursor gene expression vector into agrobacterium root carcinoma through genetic engineering methods of getting the transformation plant in order to study the effect of UV-B radiation on plant mechanism,and provide reliable scientific basis for agricultural production.This paper studies the expression of miR408,photosynthetic function change and antioxidant properties in Arabidopsis and rice under the stress of enhanced UV-B radiation so that this can provide theory basis for the plant breeding in field of resistance to UV-B radiation.(1)The report is building the rice miR408 special expression vector PCXUN,and successfully using root carcinoma of agrobacterium-mediated genetic variations to get the transgenic rice plants.(2)Overexpression of miR408 transformation of arabidopsis and rice plants in UV-B radiation stress are compared with the other groups are showed a more serious condition that the height of the plants is decreased,the cotyledons and leaves is curlied.This condition showed that overexpression of miR408 arabidopsis and rice under UV-B radiation stress are growth more serious.Resistance to UV-B radiation stress is reduced,photosynthesis and antioxidant system are affected.miR408 have important regulatory role in resistance of arabidopsis and rice.(3)Overexpression of miR408 transformation of arabidopsis and rice plants in UV-B radiation stress are compared with the other groups are showed a more serious condition that the content of chlorophyll a and chlorophyll b is decreased,chlorophyll fluorescence kinetics parameter Fv/Fm,qP value decreased,qN number increases,affected the process of photosynthesis of plants.At the same time,the activity of antioxidant system enzymes SOD,CAT,POD are decreased,the content of oxidation material MDA increased,affected plant resistance to radiation,damaged to plant growth and development process.This condition showed that overexpression of miR408 arabidopsis and rice under UV-B radiation stress are growth more serious.Resistance to UV-B radiation stress is reduced,photosynthesis and antioxidant system are affected.miR408 have important regulatory role in resistance of arabidopsis and rice.(4)Semi-quantitative RT-PCR analysis showed that: Overexpression of miR408 transformation of arabidopsis and rice plants in UV-B radiation stress are compared with the other groups are showed higter quantity expression.From the angle of molecular further show that miR408 excessive expression make the resistance to UV-B radiation stress is reduced,photosynthesis and antioxidant system are affected.miR408 have important regulatory role in resistance of arabidopsis and rice.