Skip to main content
ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #65445
Title: MOLECULAR DETERMINATION OF A B GENOME PROGENITOR OF WHEAT (TRITICUM AESTIVUM) USING A GENOME-SPECIFIC REPETITIVE DNA SEQUENCE.

Author
item DAUD, HASSAN - BIOTECH CENTER MALAYSIA
item Gustafson, J

Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Scientists and breeders have long been trying to establish the origin of the third parental donor of hexaploid wheat (three genomes, A, B, and D, make up hexaploid wheat); two of the species donors are well known. The establishment of the remaining donor will make the manipulation of genes from wild species into wheat for cultivar improvement much easier. The present study was designed to establish the remaining donor using molecula techniques. By isolating a species-specific DNA marker we were able to establish that the origin of the last remaining genetic component of bread wheat came from a wild species called Triticum speltoides.

Technical Abstract: In polyploid wheat, the origin of the B-genome donor has remained relatively unknown in spite of a number of investigations attempting to identify the parental species. A genome-specific DNA sequence was cloned from Triticum speltoides L. for determining if that species could be the B-genome donor. A cloning scheme involving the pre-screening of 1kb fragments followed by colony, dot blot, and Southern blot hybridization screenings was used to isolate a speltoides-specific sequence (pSp89.X1). The methods used allowed for rapid isolation of a genome-specific sequence when screened against total DNA from closely related species. The sequence was not detected in any other genomes of the annual Sitopsis section. The results of dot blot, Southern blot, and in situ hybridization analyses established that 1) the T. speltoides-specific DNA sequence pSp89.X1 was present on both arms of seven chromosome pairs present in tetraploid and hexaploid wheat; 2) the presence of pSp89.X1 seemed to decrease in content from the diploid to the polyploid wheats; and 3) the existence of a related, but modified B-genome in polyploid wheat as compared to that in modern T. speltoides was probable.