Identiifcation And Genetic Analysis Of Common Wheat-Agropyron6P Translocation Lines

Agropyron cristatum (L.) Gaertn chromosome6P contains a lot of excellent genes for wheatimprovement. So it is very important for the genetic research of6P chromosome to identify wheat-Agropyron6P translocation lines and develop molecular markers specific to6P. In this study, wedeveloped EST markers specific to the A. cristatum6P chromosome using the wheat-A. cristatum6Pdisomic addition line4844-12(2n=44) and its common wheat parent 'Fukuho' as well as A. cristatumaccession Z559(2n=4X=28, PPPP), then detected the offspring of wheat-Agropyron6P addition linesand common wheat'Gaocheng8901'with these markers. Positive plants which showed positive by6P-spicific markers were detected by GISH and FISH to identify their type of translocation. Locating the6P-specific molecular markers with these wheat-A. cristatum6P translocation lines, which is used todetermine the relationship among these6P translocation fragments. At the same time,traits of obtainedwheat-A. cristatum6P translocation lines were conducted to analyze the genetic effects brought bytranslocation fragments in common wheat background. The results are as following:1. A total of1306P-specific molecular markers were developed from1453PCR primers designedaccording to the sequences of ESTs gained from the transcriptome sequencing of A. cristatum.2. four wheat-Agropyron translocation lines were found in the self-progeny offspring of SM2-244by in situ hybridization (ISH) and EST markers, which are one large-fragment translocation line27-9(T6PS.6PL-5AL), one small-fragment translocation line37-1(T6PL-5AL.5AS),small-fragment line65-5(T6PL-3BS.3BL) and one arm-side additional translocation line9-1(T6PL-5AL.5AS+T6PS.6PL).The translocation fragments from27-9and37-1constitute a completely6P chromosome. Thetranslocation fragment from65-5were confirmed to be one part of37-1′s by EST markers. The threetranslocation lines divided6P chromosome into four parts: there are56markers located on the short armof6P chromosome,20markers located on the0.00-0.32section of long arm of6P chromosome,30markers located on the0.32-0.69section of long arm of6P chromosome,24markers located on the0.69-1.00section of long arm of6P chromosome.3. The biological characteristics of different translocation lines shows that small-fragmentstranslocation line37-1has longer spikes, more grains per spikelet and spike compared to wheat parent.While large-fragment translocation line27-9has shorter spikes, less grains per spikelet and spikecompared with wheat parent, but its spike type is similar with wheat parent. Which suggests that the twoalien segments carries spike-related genes. The number of kernels per spike of the two translocation linesare much less than wheat-A. Cristatum6P disomic addition line4844-12(2n=44), and the reason ofcausing superior numbers of florets and kernels per spike is complicated. There are some genes relatedto spike length on the0.32-1.00section of long arm of6P chromosome.4. These specific markers were matched with protein database from NCBI and wheat EST sequenceto understand the potential function genes on chromosome6P and the gene synteny between A. cristatum and common wheat. The results showed that the function annotation of four A. cristatum EST sequencesare related to disease and stress resistance; Thirty six A. cristatum EST sequences could be matched withthe located wheat EST bin map, in which33(91.67%) sequences were located in the sixth homoeologousgroup.Conclusion:1306P-specific molecular markers and4wheat-A. Cristatum6P translocation lineswere gained in this study, which is helpful to the6P chromosome genetic research. The genes causingsuperior numbers of florets and kernels per spike may exist on both of the long and short arm. Here aresome genes related to spike length on the0.32-1.00section of long arm of6P chromosome.