Analysis And Identification Of Salt-Tolerance Polygenes GY11 Expression In Rice

Salt injury is one of the most important abiological stresses on agricultural production. Rice is one of the most important food crops in the world, and almost half the world’s population depends on rice as their staple food. Salt damage severely restricts the rice production, and causes severe yield reduction and quality degradation. At present, salinization of arable land in Ningxia has accounted for 1/3 of the entire arable land of Yang Huang irrigation area and the salinization is set to intensify. Therefore, cultivating salt-tolerant rice is so important for reasonable exploitation of saline-alkali soil, and increasing the grain output. In this study, we use the polygenes expression vector GY11 as the research object, and the 27th receptor materials as the control. My research identified the expression and salt resistance of transgenic plants via molecular detection, indoor germination stage of salt tolerance, and physiological index detection and salt tolerance in field. Thus, we can establish a good foundation for the rice salt tolerant breeding. The main findings are as follows:(1)Molecular detection:PCR test results:transgenic plants 86,87,88,89 amplified the target genes; RT-PCR test results:target genes GY1, GY2 expressed in 86,88,89, but GY3, GY4 did not express in all plants. The function of gene expression analysis:the rice strain cultivated for 15 days then treat with 150mM NaCl for different times, the RT-PCR results shows:with the treatment of 48h,72h and 96h salt stress, GY1 and GY2 gens are expressed in 86,88,89, but did not express in 87 until 96h. Conversely, GY3gene did not express in all time; then the GY4 gene is not expressed in 48h,72h, but are expressed in 86,87,88,89 until 96h.Therefore, we speculate that functional expression of genes related to salt stress time.(2)Identification of the salt tolerance of rice in bud stage:Treat the rice strain cultivated for 15 days with OmM、125mM、150mM and 200mM NaCl relatively, after 3 days measure the germinating biability and after 7 days measure the phenotypes including germination percentage, root length, shoot length, principal root number. The result shows that with the treatment of 150mM NaCl salt stress, the germinating biability, germination percentage and root length of 86, 88 and 89 transgenic plants outweigh the control groups dramatically. Among them,88 is the longest root, heaviest fresh weight transgenic plant and the shoot length and has a significant difference; 87 is the maximum principal root number, and has a significant difference. Through multivariate analysis, I categorize the five transgenic plants into three types:salt-sensitive strains (84 strain’s salt tolerance is weak), moderate salt-tolerant strains (87&89 strain’s salt tolerance is moderate) and salt-tolerant strains (86&88 strain’s salt tolerance is high).Measurement of physiological indices of transgenic strains:Through the measurement of the strains’proline content, MDA and catalase activity, I found that with the increase of stress time, the transgenic strains’proline content and catalase activity exceed the control group, but the MDA is less than the control group. The result illustrates that transgenic strains have relative higher salt tolerance.(3) Field identification of salt tolerance:Through the identification and selection with the five transgenic strains experienced the selection of salt tolerance in experimental field of Ningxia Xidatan Core Experimental Area, I measure the survival rate of seedlings in the fields, mature height, panicle length, grain number and GYPP and the result shows that the germination rate of 86,87,88 and 89 transgenic strains all higher than the control groups and have a significant difference. Among them,89 has a maximum plant height, over 70cm,1.87g panicle weight and 105 panicle and 13.5g GYPP, which indicates that the salt tolerance of 89 strains surpass the control strains.