Chromosome Location And Molecular Mapping Of Desirable Genes In The Derivatives Between Triticum Aestivum L. And Agropyron Cristatum (L.) Gaertn

The wild relatives of common wheat (Triticum aestivum L.) are a potential gene reservoir for wheat improvement. It's very important economically and theoritically understanding that how to earthout, transfer and utilize some of desirable genes such as genes for biostress and abiostress resistance from the wild relatives of wheat. Agropyron cristatum Gaertn (P Genome) has been found to possess many sort of desirable traits distinguished by their high level of drought and cold tolerance, disease resistance and better plant-shape benefit to high yield, that are potentially valuable for wheat improvement.Based on the breakthrough of hybridization between common wheat (Fukuho) to A. cristatum (Z559) and following the F1 plant selfing and backcross to Fukuho, Many wheat-wheatgrass alien disomic addition lines and derivatives were produced by cytogenetical and Fluorescence In Situ Hybridization (FISH) identified methods. In this experiment, there is a systematical design to understand all probably desirable genes on each chromosome of P genome under typical test conditions with a full set of wheat-A. cristatum alien disomic addition lines. Meanwhile, an excellent powdery mildew resistance gene originated in A. cristatum (Z559) was mapped to wheat homologous group with SSR markers throughout construction and molecular marker analysis of a DH population of F1 hybrid between Wula, an A. cristatum derivative holding resistance gene, to Wenmai No. 6, a common wheat variety susceptible to powdery mildew. A new powdery mildew resistance gene was named combining data for response pattern and genetic location. The main successful results were shown as followings:With four Erysiphe graminis isolates, E09, E17, E21 and E26 presently each with low, moderate and high virulence to cropping wheat cultivars in China,This full et whest-A.cristatum disomic addition lines were used to artifical inoculation at adult-plant stage, and seedling stage by leaf segment identification method to evaluate their resistance response. It's shown that the powdery mildew resistance genes locate at 2P and 7P chromosomes, and maybe appear in 3P or 6P chromosome. All these resistant genes could express fine under common wheat genome background. Yellow rust and leaf rust resistance identification were engaged in low-temperature growth chamber and field with mixture spore inoculated of 4 yellow rust isolates and 8 leaf rust isolates, respectively. The results indicated the gene resistant to yellow rust was located on 6P chromosome, with moderate degree resistance in wheat background. But genes for leaf rust resistance with immunity response were pointed on 3P, 7P and 2P chromosome. These genes could sufficiently express in wheat background, will being important gene reservoir in wheat breeding for leaf rust resistance.The drought resistance identification of the full et of disomic addition lines with the method of "repeated drought periods" indicated that genes for drought resistance mainly scatter in the 2P, 4P, and 7P chromosomes. The resistant strength of each disomic addition line was lower than the A. cristatum parent. The genes for cold tolerance were located on 4P and 6P chromosomes. This cold tolerance response was weaker than the parent A. cristatum.Identification of genes for some of the important agronomic traits originated in A.cristatum shown that: genes related to vernalization marked with creeping stem, curl or semi-curl and dark green leaf in seedling stage were located on 2P, 3P and 5P chromosomes; genes controlling tiller number were being 2P and 6P, and genes for potential high yield characterized by many spikelet number, many floscular number, longer peduncle length, and shorter plant height were located on 5P chromosomes but with an undesirable late maturity gene. Additionally, gene(s) for awnlessness appeared on 3P, 6P chromosomes.By electrophoresis gel analysis of HMW glutenin subunits in seed of a set of wheat-A.cristatum addition lines and A.cristatum, it's shown that there are genes in A. cristatum (Z559) inhibiting the expression of HMW glutenin subunits under wheat background. The HMW glutenin genes of A. cristatum (Z559) no express, the female Fukuho possesses 5 subunits: 2．2+12 (encoded by D genome), 2* (A genome) and 7+8 (B genome), but the being of P chromosome had alternative inhibition effect to expression of 2．2 and 12 subunits encoded by D genome in different wheat-A.cristatum alien addition lines.The expression pattern of genes for gliadin subunits of A. cristatum < L. > Gaertn (Z559) was identified. There were richω-gliadin subunits in Z559 but disappeared all these subunits in the 16 wheat-A. cristatum alien addition lines including a addition line with 1P marker. It's already clear thatω-gliadin is controlled by gene family of the first homologous group, so, perhaps there are two kind of situations: default 1P addition line or disable expression ofω-gliadin genes under wheat background. Two specificα-andβ-gliadin subunits were taken out in four 6P addition lines and Z559 resemble to two strong gluten wheat varieties, Marquis and McGuire. It's indicated that theseαandβ-gliadin genes could be not only resources of quality improvement for wheat but 锘縜lso biochemical markers of 6P chromosome. Otherwises, changes ofè …and纬-gliadin subunits was discovered in wheat-A. cristatum derivatives Wula and Lo12．鈽匒 new powdery mildew gene originated in A. cristatum was named based on data of molecular mapping and response pattern analysis. Wula, a wheat-A.cristatum derivative, selected from BC₂ of hybrid Fukuho脳Z559 by pedigree possesses gene immune to powdery mildew. Response pattern analysis indicated that this gene immune to almost all the powdery mildew isolates except to E21 with middle resistance. By establishing DH population of Wula脳Wenmai No.6(susceptible), genetic location and molecular mapping of the powdery mildw gene were carried out. The response pattern of DH families showed 1:1 ratio of resistance to susceptible individuals indicates that the resistance controlled by a single dominant gene. Bulked segregant analysis was used to identify microsatellite markers linked to the gene. Three SSR markers Xgwm341, Xgwm383 and Xgwm645 were mapped in coupling phase to the gene locus, thus, this resistance gene was located on long arm of 3D chromosome. The gene was mapped between Xgwm341 to Xgwm383 with 29．4cM and 26．6cM respectively. And Xgwm645 was mapped 26．4 cM out of Xgwm341．Because there hasn't been powdery mildew gene was located on 3DL until now, so, this is a new powdery mildew resistance gene originated in A. cristatum. It is designated Pm31 tentatively. The paper discussed the propably utilization of these important gene resources, given the suggestions and the perspects in the future.