【摘要】 为筛选出蒙古冰草（Agropyron mongolicum Keng）抗旱相关的XTH基因，利用生物信息学方法对其理化性质、亚细胞定位、保守基序、进化关系及二、三级结构进行分析，并对4个抗旱相关的XTH基因进行表达分析。结果表明：筛选得到的7个蒙古冰草XTH基因，蛋白大小位于70～357 aa，分子质量为7.67～39.46 ku，理论等电点（PI）在4.67～9.81，均为亲水性蛋白；亚细胞定位表明AmXTH-1定位在细胞壁和细胞质，其余6个定位于细胞壁。XTH基因的二、三级结构以无规则卷曲为主，推测motif1、motif2和motif3为保守基序。进化关系比对发现AmXTH30、AmXTH28-1、AmXTH-1和AmXTH8-1与已知具有抗旱功能的基因具有较高相似性。qRT-PCR分析表明，4个与蒙古冰草抗旱相关的XTH基因均呈下调表达。推测蒙古冰草中差异表达的4个XTH基因在响应干旱胁迫中起负调控作用。更多还原

【Abstract】 To screen the XTH genes related to drought resistance in Agropyron mongolicum Keng, the physical and chemical properties, subcellular localization, conserved motif, evolutionary relationship and secondary and tertiary structures were analyzed by bioinformatics methods, and the expression of four XTH genes related to drought resistance was monitored. The results showed that: The seven XTH genes of A.mongolicum were hydrophilic proteins with molecular weight of 7. 67 to 39. 46 ku, the theoretical isoelectric point(PI) of 4. 67 to 9. 81, and protein size of 70 to 357 aa. Subcellular localization analysed showed that AmXTH-1 was located in the cell wall and cytoplasm, and the rest 6 genes were located in the cell wall. The secondary and tertiary structures of the XTH gene were mainly random coils, and motif1, motif2 and motif3were speculated to be conserved motifs. Phylogenetic analysis showed that AmXTH30,AmXTH28-1,AmXTH-1 and AmXTH8-1 had high similarity with known genes with drought resistance. The qRT-PCR analysis showed that the four XTH genes related to drought resistance of A. mongolicum were downregulated. It is speculated that the four differentially expressed XTH genes in A. mongolicum play a negative regulatory role in response to drought stress.更多还原