簇毛麦3V染色体变异系创制及其抗条锈基因的染色体定位

Stripe rust, is considered one of the most dangerous diseases of wheat (Triticum aestivum L.) . There is an urgent need for exploring and identifying novel effective rust resistance genes from relatives of wheat. Dasypyrum villosum possessing numerous agronomically important traits, which is considered as a valuable pool of genes for wheat disease resistance. In the previous study, we obtained a novel wheat-D. villosum 3V(3D) substitution line, CD-3 that has considerably high stripe rust resistance at the adult stage, and we deduced that the stripe rust resistance gene(s) is originated from the chromosome 3V of D. villosum by pedigree analysis. To date, we developed several wheat-D. villosum dissection lines through 60Co-γ irradiation and crossing with CS-ph1b mutant. With the aim to identified the chromosomal location of the rust resistant gene(s) and further use the gene(s), the present project will be conducted as the following steps: 1) to develop more lines possessing 3V structural mutant chromosomes using 60Co-γ irradiation and CS-ph1b mutant; 2) to obtain the resistant plant using rust resistance survey and identify accurately the plants carrying the structural changed chromosome(s) by cytological and molecular methods; 3) to primary map chromosomal position of the stripe rust resistance gene(s) in chromosome 3V through integrating the stripe rust resistance survey, cytological and molecular methods. This project will benefit for the utilization and molecular mark-assisted breeding of stripe rust resistance gene(s) and enriching the genetic resources for wheat improvement

小麦条锈病是小麦生产的第一大病害。在小麦近缘种中发掘新的条锈抗性基因在小麦抗性改良上具有重要意义。一年生簇毛麦具有多种优良性状，是小麦的优异基因源。本项目通过前期研究，筛选到一份高抗条锈的小麦-簇毛麦3V（3D）代换系，CD-3。由系谱推导，其抗条锈基因位于簇毛麦3V染色体。为明确该抗性基因所在染色体区段，从而研究利用该基因，本项目已通过辐照和CS-ph1b突变体对CD-3进行了诱导，并获得了数份小麦-3V染色体突变系。本研究拟在上述基础上开展如下研究：1）利用辐照和CS-ph1b突变体创制更多小麦-3V染色体变异系；2）通过抗性鉴定筛选出高抗条锈的小麦-3V染色体变异系，并用分子细胞学手段对变异系进行精确鉴定；3）结合抗性鉴定和分子细胞学鉴定，将分子标记和条锈抗性基因定位于3V染色体的特异区段上。上述研究将为簇毛麦条锈抗性基因的利用及分子标记辅助选育奠定基础，为小麦条锈抗性改良提供材料。

一年生簇毛麦是一种拥有多种优良性状的一年生小麦近缘种属，可用于小麦遗传改良。本项目前期鉴定到了一份高抗小麦条锈病的中国春-簇毛麦3V#3(3D)代换系, CD-3，并将其条锈抗性基因定位到了簇毛麦3V#3染色体上，命名为YrCD-3。本项目利用辐照技术，处理了CD-3种子，通过荧光原位杂交、分子标记和条锈抗性鉴定连续筛选，最终在M4代获得了两份CS-簇毛麦3V#3.3D易位系，22-12和24-20。结果显示，22-12是3V#3S.3DL易位系，24-20是3DS.3V#3L易位系。条锈抗性鉴定结果显示，22-12高抗条锈病，而24-20中感条锈病，表明YrCD-3应位于3V#3染色体短臂上。为在小麦背景下高效追踪3V#3染色体，将前人报道的18条3V#4特异EST标记定位到了3V#3染色体臂上，其中7条位于3V#3短臂上，11条位于3V#3长臂上。此外，本项目还探索了不同小麦遗传背景下，四个组合（CD-3/KL、KL/CD-3、CD-3/CM42 和 CM42/CD-3）F2代中3V#3染色体的遗传特性，结果表明，3V#3染色体在 CM42 和 KL 背景中传递率显著低于理论值（75%），且二者遗传背景对其传递率无影响。为进一步在小麦育种中利用YrCD-3, 将CD-3与四川小麦品种进行杂交，并从BC1F2代中筛选到了一份高抗小麦条锈病的川麦60-簇毛麦3V(3D)代换系，1901-245。以上高抗小麦条锈病的小麦-簇毛麦异源材料的获得为小麦抗性育种提供了宝贵的资源材料，筛选到的3V#3特异EST标记也为YrCD-3的进一步挖掘和利用提供了技术保障。