No abstract

Background Iron deficiency is a well-known nutritional disorder, and the imbalance of trace-elements, specifically iron, is the most common nutrient deficiency of foods across the world, including in Kazakhstan. Wheat has significant nutritional relevance, especially in the provision of iron, however many bread wheat varieties have low iron despite the need for human nourishment. In this study, the expression profiles of wheat homologous genes related to iron homeostasis were investigated. The work resulted in the development of two new M5 mutant lines of spring bread wheat through gamma-irradiation (200 Gy) with higher grain iron and zinc content, lower phytic acid content, and enhanced iron bioavailability compared to the parent variety. Mutant lines were also characterized by higher means of yield associated traits such as grain number per main spike, grain weight per main spike, grain weight per plant, and thousand-grain weight. Methods The homologous genes of bread wheat from several groups were selected for gene expression studies exploring the tight control of iron uptake, translocation rate and accumulation in leaves and roots, and comprised the following: (1) S-adenosylmethionine synthase (SAMS), nicotianamine synthase (NAS1), nicotianamine aminotransferase (NAAT), deoxymugineic acid synthetase (DMAS), involved in the synthesis and release of phytosiderophores; (2) transcription factor basic helix-loop-helix (bHLH); (3) transporters of mugineic acid (TOM), involved in long-distance iron transport; (4) yellow stripe-like (YSlA), and the vacuolar transporter (VIT2), involved in intracellular iron transport and storage; and lastly (5) natural resistance-associated macrophage protein (NRAMP) and ferritin (Fer1A). Results The wheat homologous genes TaSAMS, TaNAS1, and TaDMAS, were significantly up-regulated in the roots of both mutant lines by 2.1–4.7-fold compared to the parent variety. The combined over-expression of TaYSlA and TaVIT2 was also revealed in the roots of mutant lines by 1.3–2.7-fold. In one of the mutant lines, genes encoding intracellular iron transport and storage genes TaNRAMP and TaFer1A-D showed significant up-regulation in roots and leaves (by 1.4- and 3.5-fold, respectively). The highest expression was recorded in the transcription factor TabHLH, which was expressed 13.1- and 30.2-fold in the roots of mutant lines. Our research revealed that genotype-dependent and organ-specific gene expression profiles can provide new insights into iron uptake, translocation rate, storage, and regulation in wheat which aid the prioritization of gene targets for iron biofortification and bioavailability.

Fusarium head blight, caused mainly by Fusarium graminearum is one of the most damaging diseases of wheat. Breeding durable disease resistance cultivars rely largely on continually introgression new resistance genes, especially the genes with different defense mechanisms, into adapted varieties. The main objective of this research was to evaluate three spring wheat cultivars grown in Kazakhstan and the mutant lines of spring wheat (M 3 generations) developed on their genetic background by irradiation treatment (100 and 200 rays) for their resistance to Fusarium head blight disease and to use PCR-based DNA markers, such as SSRs markers to investigate genetic diversity in wheat germplasm. Significant differences in tolerance phenotype to Fusarium head blight were found among wheat cultivars and mutant lines. Comparing parent cv "Zhenis" M 3 mutant lines, 6(15), 6(16) and 22(1) had the highest means of Fusarium resistance at 15-day after the inoculation. M 3 mutant lines, 89(4) developed on base of cv. "Almaken" can be identified as FHB-tolerant. Three M 3 mutant lines obtained on genetic background of cv. "Erithrospermum-35" 110(1), 129(3) and 150(5) had higher level of Fusarium tolerance then parent cultivar. A total of 21 SSRs loci were used to determine genetic diversity among M 3 spring wheat lines and non-mutagenized plants.

The objective of this study was to broaden genetic variation of spring common wheat, evaluate and identify among M 5 mutant lines those with high-yield and improved grain quality characteristics. New lines were generated by initial treatment of variety of Eritrospermum-35 adapted to conditions of Kazakhstan by irradiation with 100-Gy and 200-Gy doses from a 60 Co source. Yield-associated traits including grain number and weight per main spike, grain weight (GW) per plant, and the thousand-kernel weight; grain size and grain shape variations; as well as quality characteristics such as grain protein content (GPC), iron, and zinc concentrations were evaluated. Mutant lines with high iron and zinc concentrations and high protein content were identified as those which have 1.6-3.4 and 1.4-2.9 times more as well as 3.7-16.9% more higher data of target concentrations than parental variety had, respectively. Several mutant lines showed significant increase in both grain iron and zinc concentrations. The positive correlation of grain quality parameters with grain area, length, and width suggest that they are related to each other. Wheat grain can be biofortified with micronutrients without negative impact on crop productivity using new mutant lines. Mutation breeding can significantly contribute to human health malnutrition and improve nutrition quality diet.

Seeds of the spring bread wheat variety Zhenis, registered in Kazakhstan, were irradiated with 100 and 200 Gray doses from a [ 60 Co] γ-ray radiation source. Promising advanced M 5 mutant lines were obtained and evaluated for mapping density of vernalization requirement associated dominant VRN-A1 gene and earliness related Esp-A1 candidate genes in 30 spring wheat mutant lines along with parent. Differences among generated mutant lines and parent were observed on frequency of distribution of VRN-A1 gene and Eps-A1 candidate gene alleles. Allelic variation at the VRN-A1 loci was observed in the 8 mutant lines (26.6%), mostly in 100 Gy mutant lines. A dominant (VRN) allele at its loci, which was present and indicated in these lines is sufficient to confer a spring growth habit. As for the candidate gene Esp-A1, eleven 100 Gy M 5 mutant and six 200 Gy M 5 lines, had Esp-A1 candidate gene allele. The two lines 24(2) and 43(4) carrying dominant allele of VRN-A1 had higher thousand kernel weight. Mutant lines carrying allele of Eps-A1 candidate gene found significantly differed from the parent especially in 100 Gy lines (73.3%) in flowering time.