Cytoplasm Transferring From Four Aegilops Species To Sichuan Common Wheat And Their Molecular Markers

Triticeae is a very important part of Gramineae.Triticeae is widely distributed and ecological diversity;it has very rich form and type of genetic variation,as a great gene pool of nucleus and cytoplasm.In this study,the cytoplasm in four Aegilops species were transferred to Sichuan wheat genetic background.The molecular markers for cytoplasm of two Aegilops species were developed.Moreover,genetic diversity of the chloroplast psaC gene was studied.These results are as follows:1.Transferring cytoplasm of four Aegilops species to Sichuan wheatAe.variabilis AS24,Ae.juvenalis AS 116,Ae.tauschii AS60 and Ae.ovata AS6 were hybridized and then backcrossed to common wheat.By sefing of these hybrids for several years,we obtained some nucleus-cytoplasmic hybrids of wheat.Meanwhile,we got some derivatives resistant to stripe rust derived from Ae.variabilis AS24 and Ae.juvenalis AS116,respectively.These nucleus-cytoplasmic hybrids can be further used in wheat improvement.2.Development of the molecular marker for cytoplasm of two Aegilops speciesBy comparing the entire sequence of chloroplast genomes among T.aestivum cv. Chinese Spring and some Aegilops species,we found that there were a number of insertions/deletions and thus resulted in the variations on DNA length among cytoplasm of B,D and D~2 in rbcL-cemA region,more especially in the region of the intergenic spacer between pseudo rp123gene and psaI gene.Based on this information,we designed the PCR-based markers of cytoplasm,which can reveal the differentiation of the three types of the cytoplasm of D,D~2and B on agarose gels clearly.3.Genetic information of the chloroplast psaC geneThe chloroplast psaC gene is an essential component,both for photochemical activity and stable assembly of photosystem I in higher plants.The psaC sequences from 11 Triticeae species were obtained.From sequence analysis,it revealed that:(1)psaC gene is highly conserved among species.Although there were three SNPs within the coding region of psaC gene,none of them resulted in the change in amino acid sequences;(2) In intergenic regions of psaC gene,an additional insertion of the six bases(CAAAAA) was only found in Hordeum vulgate.The insertion of DNA fragment(CAAAAA) was unique in H.vulgate,it can be used as a specific marker for this species;(3) The SNPs can be used in molecular marker development.