普通小麦-欧山羊草6U异源易位系创制与抗旱性评价

Fewer reports focus on alien introgression of drought-tolerant genes in wheat improvement. It was found that wheat - Aegilops biuncialis 6U disomic addition line manifested stronger drought tolerance than their recipient wheat in our previous research, which implied that chromosome 6U of Ae. biuncialis carried the gene(s) related to drought resistance. Development of wheat - Ae. biuncialis 6U translocation lines will integrate the drought resistant gene(s) to wheat chromosome and facilitate its utilization in wheat improvement.. In this project, wheat - Ae. biuncialis 6U disomic addition line A9041 was used as bridge material to produce wheat - Ae. biuncialis 6U translocation lines induced by CS ph1b mutant. Genomic in situ hybridization (GISH) will be used to identify the translocation lines in the progeny. Fluorescence in situ hybridization (FISH) will be applied to determine the wheat chromosomes translocated with 6U segments. In addition, the physiological and agronomic responses of wheat - Ae. biuncialis 6U translocation lines to drought stress will be investigated in the germination, seedling and adult stages under polyethylene glycol (PEG) treatment in the greenhouse and rainfed planting in the field. The lines with better drought resistance and elite agronomic traits will be screened as novel germplasms for wheat drought-resistant breeding. Furthermore, 6U specific markers will be developed through the comparative genomics approaches, which will be helpful to trace 6U chromosomal segments in wheat background and used in marker-assisted selection.

通过外源基因/基因组区段渗入改良栽培小麦抗旱性的报道较少。本课题组前期研究发现，与受体亲本相比，小麦-欧山羊草6U异附加系抗旱性显著提高。由此推断，欧山羊草6U染色体携带抗旱相关基因。创制小麦-欧山羊草6U易位系是有效利用该外源抗旱基因的重要途径。. 本项目以ph1b突变体诱导小麦-欧山羊草6U二体异附加系A9041获得的衍生系为材料，通过基因组原位杂交（GISH）和荧光原位杂交（FISH）技术，鉴定得到小麦-欧山羊草6U易位系，并且明确参与易位的小麦染色体。对获得的6U易位系进行PEG模拟和田间水分胁迫试验，在萌发期、苗期和成株期测定膜脂过氧化水平、细胞保护酶活性、叶片水分状况和光合特性等抗旱相关生理指标及产量性状，筛选抗旱能力强、农艺性状好的易位系。利用比较基因组学方法，开发6U特异分子标记，用于小麦育种过程中外源染色体相关区段的遗传追踪和辅助选择。

由于现代耕作制度，小麦种内遗传多样性急剧减少。欧山羊草（Aegilops biuncialis）携带抗病抗逆等可供小麦遗传改良的有益基因，将其导入受体小麦是改良栽培小麦的有效途径之一。本项目利用原位杂交技术（GISH、mcGISH、FISH和ND-FISH）和分子标记技术对小麦-欧山羊草衍生系材料进行了分子细胞遗传学鉴定，获得1个小麦-欧山羊草5Mb二体异附加系、1个3Ub-3D二体异代换系、3个小麦-欧山羊草异源易位系和外源渐渗系等携带外源遗传成分的远缘材料。农艺性状调查表明，5Mb染色体携带影响穗部发育相关基因、3Ub携带有高抗条锈病基因、种质WA9111携带高穗粒数基因、6份衍生系材料高抗条锈病及其他抗病抗逆材料。利用简化基因组测序技术，开发了242个欧山羊草特异SLAF标记，并将其划分为4种类型。242个标记共有298种不同扩增带型，包括172个U和M基因组通用标记，6个U基因组特异标记，102个M基因组特异标记和18个欧山羊草Y17特异标记。小麦-欧山羊草附加系、代换系和易位系的鉴定，为有效利用欧山羊草外源基因提供重要的材料基础；欧山羊草特异分子标记的获得，为快速追踪鉴定小麦背景下欧山羊草遗传成分及其他携带U和M基因组外源片段提供了分子标记。