Development And Identification Of Wheat-Aegilops Umbellulata 1U Introgression Lines

Aegilops umbellulata is the U-genome diploid species,and also the donor species of polyploid Aegilops sharing U-genome.Ae.umbellulata contains many valuable genes that can be used for wheat genetic improvement.The high-molecular-weight glutenin subunits（HMW-GS）harbored by its 1U chromosome have a large molecular masses.Introgression the HMW-GS of chromosome 1U into common wheat has the possibility to improve the enduse quality of wheat.Wheat-alien species introgression lines are important bridge materials for the transfer and utilization of excellent genes of related genera and species.In order to transfer and use the excellent genes of the 1U chromosome of Ae.umbellulata,eight wheat-Ae.umbellulata introgression lines were identified from wheat-Ae.umbellulata distant hybridization crosses of tetraploid wheat-Ae.umbellulata amphidiploid and common wheat.Molecular cytology,SNP array,reversed-phase high-performance liquid chromatography（RP-HPLC）,sodium dodecyl sulfate polyacrylamide gel electrophoresis（SDS-PAGE）,agronomic traits inspection,SDS micro sedimentation test,etc,were used to identify and analyze eight introgression lines and their parents chromosome composition and number,high-molecular-weight glutenin subunit（HMW-GS）composition,seed storage protein content.The main results are as follows:1.Using two sets of FISH probes Oligo-p Sc119.2/Oligo-p Ta535 and Oligo-p Ta71/（AAC）₅,eight introgression lines with 1U chromosomes were identified from wheat-Ae.umbellulata distant hybridization crosses STU 8/CS ph1b//Mianmai 37（MM 37）///Shumai 126（SM 126）and STU 1/Guohao 15（GH 15）//Xikemai 11（XK 11）.Six introgression lines derived from STU 8/CS ph1b//MM 37///SM 126 are disomic substitution line of 1U/1B（18 B5-45,2n=42）,dimonosomic line of 1U and 1B（18 B5-45,2n=42）,disomic substitution of 1U/1B plus one 1BL（18 B1-11,2n=43）,monosomic substitution line of 1U/1B plus one 1BL（18 B5-1,2n=42）,disomic addition line of 1U（18 B5-16,2n=44）and monosomic addition line of 1U（18 B2-1,2n=43）,respectively.Two introgression lines derived from STU 1/GH 15//XK 11 are monosomic substitution line of 1U/1D（18S2-18,2n=41）and dimonosomic line of 1U and 1D（18 S2-26,2n=42）,respectively.GISH identification showed 19 B5-28,the self-bred progeny of 18 B5-28,contained a pair of1U chromosomes.55K SNP microarray analysis showed that the number of marker deletion among chromosomes is ranged from 3 to 1394,with a deletion rate varied from 0.44% to 78.23%.Marker deletion rates of all chromsomes were below 7%except for the 6D and 1B.Of all the chromosomes,the marker deletion rate of 1B was the largest and as high as78.23%,suggesting that 1B chromosome is likely to be replaced by 1U.2.Agronomic traits such as plant height,ear length,awn length,spikelet number,tiller number,and seed setting rate were investigated for wheat-Ae.umbellulata introgression lines 18 B1-11 and 18 S2-18 and their hexaploid wheat parents.The results showed that the plant height and tiller number of 18 B1-11 were lower than those of CS ph1b and higher than other parents,the spike length and awn length were greater than those of all parents,the spikelet number was close to that of all parents,and the seed setting rate was lower than that of all parents.18 S2-18 has more tillers than that of the two parents.The grain traits such as 50 grain weight,grain length,grain width and grain aspect ratio were investigated on eight introgression lines and their parents.The results showed that the 50 grain weight of 19 B5-1（1.75±0.05 g）was the largest among all introgression lines,which was close to that of hexaploid wheat parent SM 126.The grain length of 19S2-18（7.90±0.58 mm）was the longest,which was significantly greater than that of hexaploid wheat parents GH 15 and XK 11.The grain width of 19 B5-45（2.96±0.37 mm）was the widest,which was close to that of hexaploid wheat parent MM 37.The grain length/width ratio of 19 B5-16（2.32±0.23）was the smallest,which was close to that of hexaploid wheat parent MM 37.3.SDS-PAGE and RP-HPLC analysis were conducted on eight wheat-Ae.umbellulata introgression lines.The SDS-PAGE results showed that the HMW-GS composition of B5-28（1U/1B disomic substitution line）and B5-16（1U disomic addition line）was the same between the two generations,while the HMW-GS composition of the remaining six derivative lines were different.RP-HPLC analysis showed that diploid Ae.umbellulata,tetraploid wheat-Ae.umbellulata amphidiploid and derivative lines share similar glutelin and gliadin absorption peaks at certain elution times,suggesting that these proteins may came from 1U chromosome.The HMW-GS contents of six wheat-Ae.umbellulata introgression lines derived from STU 8/CS ph1b//MM 37///SM 126 were higher than those of the three hexaploid wheat parents,while the contents of HMW-GS,LMW-GS and gliadin were lower than those of the diploid Ae.umbellulata PI 226500.The HMW-GS contents of the two wheat-Ae.umbellulata introgression lines derived from STU1/GH 15//XK 11 were intermediate of two hexaploid wheat parents,the contents of LMW-GS and gliadin were lower and higher than those of the two hexaploid wheat parents,the contents of HMW-GS,LMW-GS and gliadin of the two wheat-Ae.umbellulata introgression lines were lower than those of diploid Ae.umbellulata CIae 29,and the content of gliadin was lower than that of tetraploid wheat PI 349045.4.The SDS micro-sedimentation values of six wheat-Ae.umbellulata introgression lines,19 B5-45,19 B1-11,19 B5-1,19 B5-16,19 B2-1 and 19 S2-26,were measured.The results showed their micro-sedimentation values were significantly higher than those oftheir parents,most likely suggesting that introgression of 1U chromosome can increase the sedimentation value.