| With the deterioration of global ecological environment, drought has already caused great impacts and losses on human society and economic life as well as industrial and agricultural areas, especially inrice production.Malignant transformation of the globalnatural climate makes the drought cycle shorter and shorter, and more and more serious, which causes serious threats to grain production. Grain reduction caused by drought exceeds the sumof reduction caused by other environmental threats. Drought has been considered as one of the most important abiotic influence factorsaffecting rice production. Therefore, exploring the resources of drought resistance rice, studying the mechanism of drought resistance and then breeding the new rice varieties withdrought resistanceis an effective measure to reduce the disadvantages of drought.Dongxiang wild rice(O. rufipogon Griff., hereafter referred to as DWR) has plenty of excellent genes, and is considered as the ancestor of cultivated rice. The previous studies have shown that DWR is extreme drought resistance.Using DWR and Xieqingzao B(Oryza sativa L.)which is droughtsensitive variety as the recurrent parent, backcrossintrogression lines(BC1F9) weredeveloped. Based on these researches, this study screened two drought resistance introgression lines(M0749 and M0769), using repeated drought treatmentand the evaluation indexof seedling death rate. The average survival rateof M0749 and M0769 by repeated droughtare 91.6% and 90.5%,respectively. Meanwhile, we analyzed the physiological parameters of M0749 and its parents under the condition of normal and drought stress, the resultsshowedthat the soluble sugar, protine and soluble protein content of DWR and M0749 after drought stress treatmentincreasedsignificantly than those under normal condition, and their relative growthratesweremuchhigherthanthoseofXieqingzao B.In order to identify genes related to drought resistance, cDNA-AFLP approach was employed to identify genes differentially expressed in DWR, Xieqingzao B and introgression line M0749 under drought treatment. A total of 27 differentially expressed transcript-derived fragments(TDFs) were identified with 6 primer pairs. The TDFs presented significant similarity with the functional genes which can be classified into stress protein expression, signal transduction, transcription factors, retrotransposons, redox and unknown function proteins, and so on. Using qRT-PCR approach to verify the expression of 5 random TDFs, and the results were consist with cDNA-AFLP method. Therefore, cDNA-AFLP techniques can be applied toscreen theDWR drought resistance genes, the experimental results can provide reference for drought resistance molecular mechanism of DWR. |
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