IMPROVEMENT OF HARD RED SPRING AND DURUM WHEAT FOR DISEASE RESISTANCE AND QUALITY USING GENETICS AND GENOMICS
Location: Cereal Crops Research
Title: Homoeology of Thinopyrum junceum and Elymus rectisetus chromosomes to wheat and disease resistance conferred by the Thinopyrum and Elymus chromosomes in wheat
Submitted to: Chromosome Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 23, 2012
Publication Date: August 15, 2012
Citation: Mcarthur, R.I., Zhu, X., Oliver, R.E., Klindworth, D.L., Xu, S.S., Stack, R.W., Wang, R., Cai, X. 2012. Homoeology of Thinopyrum junceum and Elymus rectisetus chromosomes to wheat and disease resistance conferred by the Thinopyrum and Elymus chromosomes in wheat. Chromosome Research. DOI 10.1007/s10577-012-9307-y.
Interpretive Summary: Wheat is a hexaploid with the A, B, and D genomes, and each genome has seven pairs of chromosomes. The 21 pairs of wheat chromosomes are grouped into seven Groups (e.g., Group 1 includes chromosomes 1A, 1B, and 1D) based on their genetic similarity. Wheat has over 300 wild relative species, most of which are commonly known as wheatgrasses with genomes that are genetically similar to wheat genomes. Wheat-wheatgrass chromosome addition lines, which contain all the wheat chromosomes plus a pair of wheatgrass chromosomes, are useful materials for wheat improvement. In this study, we utilized Group-specific DNA and protein markers to examine the grass chromosomes in 17 wheat-wheatgrass addition lines, including 13 lines carrying a pair of chromosomes from wheatgrass species Thinopyrum junceum and four lines carrying chromosomes from Elymus rectisetus. The marker analysis revealed that among the lines carrying a Th. junceum chromosome, five addition lines carried a Group 1 chromosome, three lines carried a Group 2 chromosome, one carried a Group 4 chromosome, two carried a Group 5 chromosome, and one probably carried a Group 6 chromosome. The group of the Th. junceum chromosome in one could not be determined in this study. Among the four addition lines carrying an E. rectisetus chromosome, two had a Group 1 chromosome, and one had a Group 5 chromsome. The fourth E. rectisetus line was found to contain multiple segregating E. rectisetus chromosomes in Groups 1 - 6. Several Th. junceum and E. rectisetus chromosomes in the addition lines were found to contain genes for resistance to rusts (Ug99), leaf spotting diseases, and head blight diseases. Understanding of the relationship of the Th. junceum and E. rectisetus chromosomes in these addition lines with wheat will facilitate the utilization of the desirable genes on these chromosomes in wheat improvement.
Thirteen common wheat ‘Chinese Spring’ (CS)-Thinopyrum junceum addition lines and three common wheat ‘Fukuhokomuji’(Fuku)-Elymus rectisetus addition lines were characterized and verified as disomic additions of a single Th. junceum or E. rectisetus chromosome in the wheat backgrounds by fluorescent genomic in situ hybridization (FGISH). Another Fuku-E. rectisetus addition line, A1048, was found to contain multiple segregating E. rectisetus chromosomes. Seven CS-Th. junceum amphiploids were identified to carry 12-16 Th. junceum chromosomes. The addition lines AJDAj5, 7, 8, 9, and HD3508 were identified to contain a Th. junceum chromosome in homoeologous group 1. Two of them, AJDAj7 and AJDAj9, had the same Th. junceum chromosome. AJDAj2, 3, and 4 contained a Th. junceum chromosome in group 2, HD3505 in group 4, AJDAj6 and AJDAj11 in group 5, and AJDAj1 probably in group 6. The addition lines A1026 and A1057 were identified to carry an E. rectisetus chromosome in group 1 and A1034 in group 5. E. rectisetus chromosomes in groups 1-6 were detected in A1048. The homoeologous group of the Th. junceum chromosome in HD3515 could not be determined in this study. Several Th. junceum and E. rectisetus chromosomes in the addition lines were found to contain genes for resistance to Fusarium head blight, tan spot, Stagonospora nodorum blotch, and stem rust (Ug99 races). Understanding of the homoeology of the Th. junceum and E. rectisetus chromosomes with wheat will facilitate the utilization of the favorable genes on these alien chromosomes in wheat improvement.