Anthocyanins participate in the protection of wheat seedlings against cadmium stress

Due to anthropogenic activity, the environment is contaminated with high levels of cadmium, which is a dangerous heavy metal. At very low concentrations, cadmium is bioaccumulative and toxic to animals and plants, generating reactive oxygen species (ROS) that are destructive to cells of organisms. Anthocyanin pigments are natural antioxidants produced in various plant tissues and play a protective role under different environments. In the present study, the putative role of anthocyanins that accumulate in the grains and shoots of bread wheat (Triticum aestivum L.) in response to cadmium-induced toxicity (25 and 50 μM CdCl2) was studied at the seedling stage. For this purpose, a set of near-isogenic lines carrying different alleles of the Pp (purple pericarp) and Rc (red coleoptile) genes was used. The lines responded differently to Cd treatment. The observed changes in anthocyanin metabolism under stress conditions were dependent on the alleles of the Rc genes that determine coleoptile pigmentation and on CdCl2 concentration. In less-colored line carrying the Rc-A1 allele, the antioxidant system was unable to fully cope with oxidative stress and thus induced the synthesis of additional antioxidants, whereas in the most tolerant lines, which have darkpurple coleoptile pigmentation predetermined by Rc-A1 + Rc-D1, the level of anthocyanins in the coleoptiles was independent of stress. A protective role of anthocyanins presented in the coleoptiles of wheat seedlings was observed under moderate Cd stress (25 μM), whereas anthocyanins seemed to be ineffective as protective compounds under heavier stress

ANTHOCYANIN PIGMENTATION IN TRITICUM AESTIVUM L.: GENETIC BASIS AND ROLE UNDER ABIOTIC STRESS CONDITIONS

Anthocyanins are secondary metabolites of plants. They have a wide range of biological activity such as antioxidant, photoprotection, osmoregulation, heavy metal ions chelation, antimicrobial and antifungal activities, which help plants to survive under different stress conditions. Bread wheat (T. aestivum L.) can have purple pigmentation provided by anthocyanin compounds in different organs, such as grain pericarp, coleoptile, culm, leaf blades, leaf sheaths, glumes and anthers. However, the genetic mechanisms underlying formation of these traits as well as contribution of the pigmentation to stress tolerance have not been widely studied in wheat. The aim of the current study was to investigate molecular-genetic mechanisms underlying anthocyanin pigmentation in different wheat organs and to estimate the role of the pigmentation under different abiotic stress conditions in wheat seedlings. In the current study, near-isogenic lines (NILs): cv. ‘Saratovskaya 29’ (‘S29’) and lines i:S29Pp1Pp2PF and i:S29Pp1Pp3P developed on the ‘S29’ background but having grain pericarp coloration (genes Pp) and more intense coleoptile (Rc), culm (Pc), leaf blade (Plb), leaf sheath (Pls) pigmentation in comparison with ‘S29’, were used. Comparative transcriptional analysis of the five structural genes Chs, Chi, F3h, Dfr, Ans, encoding enzymes participating in the anthocyanin biosynthesis, was performed in different organs of NILs. It was shown that the presence of the Rc, Pc, Plb, Pls and Pp alleles conferring strong anthocyanin pigmentation induced more intense transcription of the structural genes, suggesting the genes Rc, Pc, Plb, Pls and Pp to play a regulatory role in anthocyanin biosynthesis network. To evaluate the role of anthocyanins in stress response at the seedling stage, growth ability of the NILs and anthocyanin content in their coleoptiles were assessed after treatments with NaCl (100 and 200 mM), CdCl2 (25 and 50 μM) and 15% PEG 6000 (polyethylene glycol 6000), simulating salinity, heavy metal and drought stress, respectively. Under salinity and drought stress, the level of anthocyanins increased significantly in all three NILs in comparison with untreated control, whereas under CdCl2 treatment anthocyanin content increased significantly in ‘S29’ only. The tendency of the lines having more intensive anthocyanin pigmentation to have better growth ability under stress conditions was observed. Taken together the results obtained it may be suggested that anthocyanin production in wheat seedlings is tightly related with the response to abiotic stress

Anthocyanins participate in protection of wheat seedlings from osmotic stress

Plant secondary metabolites anthocyanins are considered to play a protective role. In bread wheat (Triticum aestivum L.), anthocyanins can be observed in both adult plants and seedlings. The aim of the current study was to investigate the putative role of anthocyanins present in grains and shoots with respect to the protection of seedlings against drought. For this purpose a set of near isogenic lines (NILs) differing in pericarp and coleoptile colour was used. Water stress was created by artificial shortage of moisture under laboratory conditions. Differences among the lines were observed in a way that the lines with dark-purple grains and coleoptiles (genotype Pp-D1Pp-D1Pp3Pp3Rc-A1Rc-A1Rc-D1Rc-D1) demonstrated a higher seedling drought tolerance than plants with uncoloured pericarp and lightpurple coleoptiles (pp-D1pp-D1pp3pp3Rc-A1Rc-A1rc-D1rc-D1). Furthermore, protection of the root system and the shoot was related with the presence of anthocyanins in grains and coleoptiles, respectively

Chromosomal location and mapping of quantitative trait locus determining technological parameters of grain and flour in strong-flour bread wheat cultivar saratovskaya 29

Bread wheat is the primary bread crop in the majority of countries in the world. The most important product that is manufactured from its grain and flour is yeast bread. In order to obtain an excellent bread, grain with high physical properties is needed for flour and dough. The Russian spring wheat cultivar Saratovskaya 29 is characterized by its exclusively high physical properties of flour and dough. The purpose of this work was to identify the chromosomes carrying the main loci for these traits in Saratovskaya 29 and to map them using recombinant substitution lines genotyped with molecular markers. A set of inter-varietal substitution lines Saratovskaya 29 (Yanetzkis Probat) was used to identify the “critical” chromosomes. The donor of individual chromosomes is a spring cultivar with average dough strength and tenacity. Substitution of 1D and 4D*7A chromosomes in the genetic background of Saratovskaya 29 resulted in a significant decrease in the physical properties of the dough. Such a deterioration in the case of 1D chromosome might be related to the variability of gluten protein composition. With the help of recombinant substitution double haploid lines obtained from a Saratovskaya 29 (Yanetzkis Probat 4D*7A) substitution line the region on the 4D chromosome was revealed in the strong-flour cultivar Saratovskaya 29, with the microsatellite locus Xgwm0165 to be associated with the unique physical properties of flour and dough. The detected locus is not related to the composition gluten proteins. These locus may be recommended to breeders for the selection of strong-flour cultivars. Additionally, a QTL associated with vitreousness of grain was mapped in the short arm of chromosome 7A

Properties of grain, flour and dough in bread wheat lines with Aegilops markgrafii introgressions

Various milling parameters, wet gluten content and key dough properties were analyzed for two sister lines of bread wheat with Ae. markgrafii introgressions in genetic background of cultivar Alcedo carrying a set of sub-chromosomal alien segments on chromosomes 2AS, 2BS, 3BL, 4AL and 6DL. The lines revealed higher grain vitreousness, larger particle size of flour, and higher wet gluten content in grain compared to cv. Alcedo. The flour from these lines also showed excellent water absorption and developed more resilient dough. The introgressions in the Alcedo genome caused no reduction in 1,000-grain weight. General improvement of the grain technological properties appears to be the result of introgressions into 2AS, 2BS and 3BL chromosomes. Coincidence of locations of Ae. markgrafii introgressions in chromosome with the QTLs positions for technological traits, revealed in bread wheat mapping populations, is discussed

Effect of seed pre-sowing gamma-irradiation treatment in bread wheat lines differing by anthocyanin pigmentation

Anthocyanins are natural antioxidants able to scavenge free radicals, which appear in plant cells under various environmental stresses. In wheat, anthocyanin pigments can be synthesized in vegetative and reproductive organs. The objective of the current study was to estimate the significance of these substances for wheat seedlings protection under irradiation stress (after treatment of dry seeds with moderate doses of gamma-irradiation, 50, 100 and 200 Gy). For this goal a set of near-isogenic lines (8 NILs) carrying different combinations of the Pp (purple pericarp) and Rc (red coleoptile) alleles were used. The effect of gammairradiation on the growth parameters and anthocyanin content in coleoptiles was studied at the 4th day after germination. The germination rate was not affected, while roots’ and shoots’ lengths and fresh weights as well as root number decreased significantly under irradiation treatment. The effect was deeper under higher doses. Irradiation treatment also induced change of root morphology (‘hairy roots’). The effect of treatment on coleoptile anthocyanin content depended on allelic combination at the Rc loci. At the presence of ‘weak’ Rc-A1 allele anthocyanin content decreased, while it did not change in lines with Rc-A1 + Rc-D1 combination (NILs with intensively colored coleoptiles). Factors ‘pericarp color’ and ‘coleoptile color’ influenced vigor of the seedlings under 50 Gy, whereas under higher doses (100 and 200 Gy) these factors did not contribute to growth parameters changes. Statistically significant positive effect of anthocyanins synthesized in coleoptile (in the presence of Rc-A1 + Rc-D1 dominant alleles) on root growth of seedling germinated from 50 Gy-treated seeds was observed

A microsatellite marker for yellow rust resistance in wheat

Bulk segregant analysis (BSA) was used to identify molecular markers associated with yellow rust disease resistance in wheat (Triticum aestivum L.). DNAs isolated from the selected yellow rust tolerant and susceptible F-2 individuals derived from a cross between yellow rust resistant and susceptible wheat genotypes were used to established a "tolerant" and a "susceptible" DNA pool. The BSA was then performed on these DNA pools using 230 markers that were previously mapped onto the individual wheat chromosomes. One of the SSR markers (Xgwm382) located on chromosome group 2 (A, B, D genomes) was present in the resistant parent and the resistant bulk but not in the susceptible parent and the susceptible bulk, suggesting that this marker is linked to a yellow rust resistance gene. The presence of Xgwm382 was also tested in 108 additional wheat genotypes differing in yellow rust resistance. This analysis showed that 81% of the wheat genotypes known to be yellow rust resistant had the Xgwm382 marker, further suggesting that the presence of this marker correlates with yellow rust resistance in diverse wheat germplasm. Therefore, Xgwm382 could be useful for marker assisted selection of yellow rust resistances genotypes in wheat breeding programs