A comparative gene analysis with rice identified orthologous group II HKT genes and their association with Na+ concentration in bread wheat. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Ariyarathna, H.; Oldach, Klaus; Francki, Michael
• Is Part Of: BMC plant biology. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 20
• Publication Date: 2016-12
• Subjects: Group II HKT -- IWGS -- Rice genome -- Na+ exclusion; Plant molecular biology -- Periodicals; Botany -- Periodicals; 580.5
• DOI: 10.1186/s12870-016-0714-7
• Languages: English
• ISSNs: 1471-2229

Abstract

Abstract Background Although theHKT transporter genes ascertain some of the key determinants of crop salt tolerance mechanisms, the diversity and functional role of group IIHKT genes are not clearly understood in bread wheat. The advanced knowledge on riceHKT and whole genome sequence was, therefore, used in comparative gene analysis to identify orthologous wheat group IIHKT genes and their role in trait variation under different saline environments. Results The four group IIHKT s in rice identified two orthologous gene families from bread wheat, including the knownTaHKT2 ;1 gene family and a new distinctly different gene family designated asTaHKT2 ;2 . A single copy ofTaHKT2 ;2 was found on each homeologous chromosome arm 7AL, 7BL and 7DL and each gene was expressed in leaf blade, sheath and root tissues under non-stressed and at 200 mM salt stressed conditions. The proteins encoded by genes of theTaHKT2 ;2 family revealed more than 93 % amino acid sequence identity but ≤52 % amino acid identity compared to the proteins encoded byTaHKT2 ;1 family. Specifically, variations in known critical domains predicted functional differences between the two protein families. Similar to orthologous rice genes on chromosome 6L, TaHKT2 ;1 andTaHKT2 ;2 genes were located approximately 3 kb apart on wheat chromosomes 7AL, 7BL and 7DL, forming a static syntenic block in the two species. The chromosomal region on 7AL containingTaHKT2 ;1 7AL -1 co-located with QTL for shoot Na+ concentration and yield in some saline environments. Conclusion The differences in copy number, genes sequences and encoded proteins betweenTaHKT2 ;2 homeologous genes and other group IIHKT gene families within and across species likely reflect functional diversity for ion selectivity and transport in plants. Evidence indicated that neitherTaHKT2 ;2 norTaHKT2 ;1 were associated with primary root Na+ uptake butTaHKT2 ;1 may be associated with trait variation for Na+ exclusion and yield in some but not all saline environments.