| Rice(Oryza Sativa L.)is the most important cereal crops,which consumed a lot of water during its production.In the face of the contradiction between the shortage of water resources and the expansion of population,the cultivation of water-saving and drought-resistant rice varieties is suitable for the urgent needs of agricultural production and accordance with the national Strategy sustainable development strategy.Shanlan upland rice,as a special local upland rice variety in Hainan province,has abundant genetic diversity and abundant drought-resistant gene resources.It is also an important germplasm resource for breeding drought-resistant rice varieties.However,most of the studies on Shanlan upland rice focused on cultivation and physiological characteristics,the molecular mechanism of drought resistance of Shanlan upland rice was seldom studied.In this study,the drought resistance of 20 species of Shanlan upland rice varieties was preliminarily identified.two varieties with stronger drought resistance,Dongfang-Manpoxiang(MPX)and Baishanuo(BSN),with strong drought resistance were selected.We used 20% PEG-6000 to simulate drought stress and used high-throughput sequencing technique to study the changes of transcriptome level before and after drought stress in two varieties of Shanlan upland rice.Transcription data related to drought resistance in Shanlan upland rice were analyzed to clarify the Gene expression profiling of Shanlan upland rice under drought stress.The main results were as follows:1.Gene Level Analysis: For MPX,829 genes were differentially expressed after drought stress,including 332 unannotated genes,2,791 genes differentially expressed and 1,192 unannotated genes after drought stress in BSN.The number of differentially expressed genes of MPX which had stronger drought resistance was less than that of BSN.2.Analysis of transcription factors in differentially expressed genes: There were 58 differentially expressed transcription factors in MPX,and 184 differentially expressed transcription factors in BSN.The transcription factors of Znf family increased the most in both varieties after drought stress.3.Spatio-temporal expression of differentially expressed genes: Os10g0505900(unannotated)and Os07g0251900 were spatio-temporal expressed.The result showed the expression of Os10g0505900 increased gradually with the time of drought stress increasing(0 h,24 h,48 h and 72 h).The expression of Os07g0251900 decreased gradually with the time of drought stress increasing.4.Analysis of drought resistance of the two varieties: the drought resistance of the two varieties of Shanlan upland rice was different,and the drought resistance mechanism was also different.MPX could resist drought mainly by maintaining strong photosynthesis ability and improving anti-oxidation ability under drought stress,while BSN could improve drought resistance by producing plant hormone,increasing cutin resistance and osmotic adjustment.5.The Gene Os09g0346500(chlorophyll a/b binding protein 1R)was up-regulated 160-fold after drought stress in MPX,and was enriched in GO team and KEGG pathway.MPX can resist drought stress through the strong photosynthetic metabolic pathway through this gene under drought stress.Based on the study of drought-resistance phenotype of Shanlan upland rice,the transcriptome expression of drought-resistance-related genes in Shanlan upland rice was analyzed by Illumina second generation high-throughput sequencing technique.It is of great significance to explore the drought-resistant genes of Shanlan upland rice and study the drought-resistant mechanism of Shanlan upland rice so as to provide reference for breeding drought-tolerant rice varieties. |
