The Ha locus of wheat: identification of a polymorphic region for tracing grain hardness in crosses.
The grain softness proteins or friabilins are known to be composed of three main components: puroindoline a, puroindoline b, and GSP-1. cDNAs for GSP-1 have previously been mapped to group-5 chromosomes and their location on chromosome 5D is closely linked to the grain hardness (Ha) locus of hexaploid wheat. A genomic DNA clone containing the GSP-1 gene (wGSP1-A1) from hexaploid wheat has been identified by fluorescent in situ hybridization as having originated from the distal end of the short arm of chromosome 5A. A genomic clone containing the gene (wGSP1-D1) was also isolated from Aegilops tauschii, the donor of the D genome to bread wheat. There are no introns in the GSP-1 genes, and there is high sequence identity between wGSP1-A1 and wGSP1-D1 up to 1 kb 5' and 300 bp 3' to wGSP1-D1. However, regions further upstream and downstream of wGSP1-D1 share no significant sequence identity to corresponding sequences in wGSP1-A1. These regions therefore identified potentially valuable sequences for tracing the Ha locus through assaying polymorphic DNA sequences. The sequence from 300 to 500 bp 3' to wGSP1-D1 (wGSP1-D13) was mapped to the Ha locus in a mapping population. wGSP1-D13 was also tightly linked to genes for puroindoline a and puroindoline b which have been previously mapped to be at the Ha locus. In addition wGSP1-D13 was used to detect RFLPs between near isogenic soft and hard Falcon lines and in a random selection of soft and hard wheats.
Turner
M
M
CSIRO Plant Industry, Canberra, ACT, Australia.
Mukai
Y
Y
Leroy
P
P
Charef
B
B
Appels
R
R
Rahman
S
S
D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D018744:DNA, Plant; D017343:Genes, Plant; D018745:Genome, Plant; D015698:Genomic Library; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010940:Plant Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D014908:Triticum / Q000235:genetics*
D018744:DNA, Plant; C088852:GSP-1 protein, Triticum aestivum; D010940:Plant Proteins