Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2006
Publication Date: 7/1/2006
Citation: Simeone, M., Gedye, K.R., Mason-Gamer, R., Gill, B.S., Morris, C.F. 2006. Conserved regulator elements identified from a comparative puroindoline gene sequence survey of triticum and aegilops diploid taxa. J. Cereal Sci. 44:21-33. Interpretive Summary: Wheat geneticists, breeders, and others concerned with the end-use qualities of wheat have recently become interested in kernel texture imparted by puroindoline proteins. This paper describes the flanking and coding region sequences of puroindoline genes from 25 accessions of the Triticum and Aegilops diploid taxa. The diploid progenitors of hexaploid wheat provide insight into the genetic sources of variation in puroindolines and thus wheat texture. Despite finding 24 new and unique puroindoline sequences that were identified through the course of this work, it was shown that, overall, the basic structure of the puroindolines was remarkably retained.
Technical Abstract: Kernel texture (“hardness”) is an important trait that determines end-use quality of wheat (Triticum aestivum L. and T. turgidum ssp. durum [Desf.] Husn.). Variation in texture is associated with the presence/absence or sequence polymorphism of two proteins, puroindoline a and puroindoline b. This work describes the flanking and coding region sequences of puroindoline genes from 25 accessions representing wild diploid taxa of the Triticeae related to the three genomes of T. aestivum. Analysis of variation at the nucleotide level included hard and soft T. aestivum wheat cultivars. Various degrees of insertions/deletions and point mutations were found, that did not affect the overall sequence structure identity. Nucleotide sequence comparisons and database searches facilitated the identification of the 5’ proximal regulating regions, revealing the presence of several putative control elements. An absolute conservation of some known regulatory elements for tissue specificity was observed, while different rates of conservation of reiterated motifs with possible enhancer functions, and the exclusive presence of some elements either in puroindoline a or puroindoline b were also found. A total of 24 new puroindoline alleles (unique sequences) were identified. Despite some primary structure variation, the main features of puroindolines, i.e. the signal peptide, the cysteine backbone, the tryptophan-rich domain, the hydrophobicity and basic identity of the proteins were all conserved.