Different Alfalfa Varieties' MRNA Relative Contents Of PhyA,phyB In Different Photoperiod Treatments

In recent years, because of crop structure adjustment and the rapid development of animal husbandry, alfalfa acreage expanded dramatically to address the imminent production of selecting varieties of fall dormancy.In order to explore the mechanism of the international community clearly fall dormancy problems ,we need breakthroughs for the urgent need dormancy At present, the study of fall dormancy mechanism is a few. Some studies indicate that Phytochrome(phy) ,the important receptor of light in plant is related to alfalfa fall dormancy .there are two phytochrome genes named A and B, which is related and restrict each other in phytochrome family .Low temperature and short day is caused by fall dormancy of alfalfa the major environmental factors, phyA, phyB photoreceptor are the main regulator of the fall dormancy alfalfa. In order to explore the phyA, phyB in alfalfa in the regulation and control mechanism in fall dormancy, the test is divided into two part s:temperature test: In short day (8 h), the study of different temperature 5℃, 15℃, 25℃, 35℃type of fall dormancy of alfalfa (Vernal) phyA, phyB mRNA relative content; light cycle test;The SYER Green fluorescent dye method is to determine the different photoperiod (8 h, 12h, 16 h) and (6 h, 12h, 18 h) three types of fall dormancy of alfalfa-type phyA, phyB mRNA relative content.First,we devised a pair of primers according to actin genes coding region sequence from Medicago Truncatula. Total RNA was isolated from the leaves of Medicago Sativa, and then obtained the objective gene cDNA. After the cDNA gene was sequenced,it was blasted in NCBI with other plants. Results demonstrated that the sequence is actin gene of the Medicago Sativa′s Actin gene fragments. And then we can go further the experiment.Temperature tests used semi-quantitative RT-PCR method (gray-scale analysis )to determine fall dormancy alfalfa phyA, phyB mRNA relative contentin on 8h (short day) conditions, phyA at a lower temperature synthesis is under of high temperature capacity, and phyB at a lower temperature synthesis is more than high temperature capacity, which shows that phyA, phyB exist ing interaction effects, or it may be with other family members of phytochrome interaction, short day phyB synthesis more at the low-temperature than high-temperature,This shows that phyB played a more important role in the regulation and control fall dormancy.Photoperiod experiment used FQ-PCR SYBR-Green to measure different fall dormancy alfalfa type phyA, phyB mRNA expression under the conditions of different photoperiod,the testing indicated that in the short sunlight conditions, phyA, phyB mRNA with a high level, which is similar with phyB protein level,the fall dormancy alfalfa can synthesis more Phytochrome, the law of fall dormancy -5 and fall dormancy-8 alfalfa are obvious regularity; phyA is not very clear,and this shows phyB plays a major role,not phyA..