Comparative Study On Gene Expression Difference Of Diploid And Tetraploid Rice Under NaCl Stress

In this experiment,diploid rice 93-11 and homologous tetraploid rice 93-11 were selected as the basic materials.By measuring period of germination and seedling period of physiological and biochemical indicators,for both in the period of germination and seedling period to study the salt resistance of two phases,and combining the transcriptome sequencing technology,analysis of diploid and tetraploid rice in 93-11 under NaCl stress differences in gene expression,at the molecular level to reveal the salt tolerance mechanism of diploid and tetraploid rice and dealing with the NaCl stress rice gene expression differences.This provides a theoretical basis for better utilization of tetraploid rice germplasm,salt tolerance gene discovery and new varieties selection of rice tolerance.The following are the main conclusions of this experiment:1.The effects of NaCl stress on the salt tolerance indexes of diploid 93-11 and tetraploid 93-11 during seed germination were basically the same.Under 50-100 mmol / L NaCl stress had little effect on germination rate,germination potential,plant height,root length,root number and other indicators,while under 150-200 mmol / L NaCl stress had a greater effect on both.However,under the stress of high concentration of NaCl,except that the germination potential of tetraploid 93-11 seeds was affected more than that of diploid 93-11 seeds,other indexes were all affected less than that of diploid 93-11 seeds,indicating that the salt tolerance of tetraploid 93-11 seeds was stronger than that of diploid 93-11 seeds at the germination stage.2.During the three-leaf one-heart period of rice,150mmol/L NaCl was used for stress.The physiological and biochemical indexes of rice seedlings under different stress periods were basically the same.But in the stress cycle,tetraploid 93-11 seedlings of proline,soluble sugar,chlorophyll,SOD,POD index were significantly higher than that of diploid 93-11,malondialdehyde and conductivity were significantly lower than that of diploid 93-11,indicating that homologous tetraploid rice 93-11 had stronger antioxidant capacity,less cell damage and better ability to accumulate osmoregulatory substances than diploid rice 93-11.3.Under 150 mmol/L NaCl stress for 6 hours,transcriptome sequencing analysis was performed on the three-leaf one-heart period of diploid and tetraploid rice seedlings. Sequencing results showed that NaCl stress caused a total of 4,930 differentially expressed genes of diploid 93-11,including 3099 up-regulated genes,1831 down-regulated genes,and the number of differentially expressed genes of tetraploid 93-11 was 5850,of which 3540 were up-regulated genes and 2310 were down-regulated genes.After GO and KEGG metabolic pathway analysis,found that compared with both main enrichment of differentially expressed genes in plant hormone signaling pathways,and compared with tetraploid 93-11 in the corn grain,terpenoids acid and alpha linolenic acid plant hormone synthesis and metabolic pathways of higher protease than diploid 93-11,through q PCR analysis of related genes in the jasmonic acid signaling pathway,it found that tetraploid 93-11 had certain advantages in regulating the expression change and response time of some genes,this suggested that chromosome doubling made tetraploid 93-11 had more complex response mechanisms in response to NaCl stress and may be more adaptable than diploid rice.