新麦草种质染色体倍性鉴定及基因组估测

Identification of chromosome ploidy of Psathyrostachys juncea germplasm and prediction of genome size

【目的】利用流式细胞仪检测新麦草种质的染色体倍性和基因组大小,为新麦草的种质鉴定及遗传育种研究提供基础数据。【方法】以31份新麦草种质为材料,利用流式细胞仪检测新麦草种质染色体倍性、核DNA含量,通过根尖染色体压片法验证检测结果。同时用已知基因组大小的黑麦草(Lolium perenne L.)和大麦(Hordeum vulgare L.)为对照,采用外标法估测新麦草的基因组大小。【结果】31份新麦草种质中,四倍体材料2份,分别为200803和595289号,占新麦草种质的6.45%;其余29份材料均为二倍体,占新麦草种质的93.55%。二倍体新麦草基因组大小为6.73 Gb,核DNA含量为(13.74±0.483)pg,四倍体新麦草基因组大小为13.62 Gb,核DNA含量为(27.842±0.681)pg。经根尖染色体制片法验证,二倍体新麦草种质体细胞染色体数为2n=2x=14,四倍体新麦草种质染色体数为2n=4x=28。根尖压片法和流式细胞仪法对新麦草种质染色体倍性鉴定结果完全一致。【结论】明确了新麦草种质的染色体倍性及基因组大小。

【Objective】This study used flow cytometry to identify the chromosome ploidy and genome size of Psathyrostachys juncea germplasm materials for providing basis for genetic research,breeding and utilization.【Method】A total of 31 Psathyrostachys juncea germplasms with different ploidy levels were tested using the flow cytometry.DNA contents of P.juncea germplasms were detected and the genome size of P.juncea was estimated using perennial ryegrass(Lolium perenne L.)genome and barley(Hordeum vulgare L.)genome as reference.The ploidy level detection of flow cytometry was validated by the root tip cell chromosome microscopic counting.【Result】Of the 31 P.juncea germplasms,2 germplasms(200803 and 595289)were trtraploid,accounting for 6.45% of the total germplasms.The rest 29 germplasms were diploid,accounting for 93.55%.The genome size of diploid P.juncea was 6.73 Gb and nuclear DNA content was(13.74±0.483)pg,while trteaploid was 13.62 Gb and nuclear DNA content was(27.842±0.681)pg.The root tip cell chromosome microscopic counting showed that the chromosome number of diploid P.juncea was 2n=2x=14,and the chromosome number of trtraploid P.juncea was 2n=4x=28,which was consistent with the identification results of flow cytometry.【Conclusion】The chromosome ploidy and genome size of P.juncea germplasm were clarified.