Two lines, L-19-613 and L-19-626, were produced from the common wheat cultivar Longmai 19 (L-19) by six consecutive backcrosses using biochemical marker-assisted selection. L-19 (Glu-D1a, Glu-A3c/Gli-A1?; Gli-A1? is a gene coding for unnamed gliadin) and L-19-613 (Glu-D1d, Glu-A3c/Gli-A1?) formed a set of near-isogenic lines (NILs) for HMW-GS, while L-19-613 and L-19-626 (Glu-D1d, Glu-A3e/Gli-A1m) constituted another set of NILs for the LMW-GS/gliadins. The three L-19 NILs were grown in the wheat breeding nursery in 2007 and 2008. The field experiments were designed using the three-column contrast arrangement method with four replicates. The three lines were ranked as follows for measurements of gluten strength, which was determined by the gluten index, Zeleny sedimentation, the stability and breakdown time of the farinogram, the maximum resistance and area of the extensogram, and the P andWvalues of the alveogram: L-19-613 > L-19-626 > L-19. The parameters listed above were significantly different between lines at the 0.05 or 0.01 level. The Glu-D1 and Glu-A3/Gli-A1 loci had additive effects on the gluten index, Zeleny sedimentation, stability, breakdown time, maximum resistance, area, P and W values. Although genetic variation at the Glu-A3/Gli-A1 locus had a great influence on wheat quality, the genetic difference between Glu-D1d and Glu-D1a at the Glu-D1 locus was much larger than that of Glu-A3c/Gli-A1? and Glu-A3e/Gli-A1m at the Glu-A3/Gli-A1 locus. Glu-D1d had negative effects on the extensibility and the L value compared with Glu-D1a. In contrast, Glu-A3c/Gli-A1? had a positive effect on these traits compared with Glu-A3e/Gli-A1m.
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.
Authors:N. Sinha, V. Priyanka, K.T. Ramya, T. Leena, J.A. Bhat, Harikrishna, N. Jain, P.K. Singh, G.P. Singh, and K.V. Prabhu
Abiotic stresses are major constraints to wheat productivity in many parts of the world. Tolerance to abiotic stresses can be achieved indirectly by selection for morpho-physiological traits. Physiological trait based breeding has been associated with improved performance under stress; and hence can combat and adapt wheat to drought and heat stress. Therefore, in the present study, phenotyping was carried out for agro-physiological traits in 52 diverse wheat germplasm lines under timely sown, rainfed and late sown environments for two years. Mean yield of the genotypes over the six environments were positively correlated with NDVI, days to maturity and negatively correlated with canopy temperature. The phenotypic data validated marker-trait associations of a number of meta-QTLs identified earlier for different physiological and agronomic traits. Six and seven meta-QTL genomic regions were found to be consistent in their expression for two years under rainfed/restricted irrigation and late sown environments, respectively. Expression analysis of the underlying candidate gene AK248593.1 in meta-QTL26 region revealed two folds higher expression in the NILs carrying the co-localized SSR markers. The linked markers of the thirteen meta-QTL regions associated with different traits can be used for effective transfer of the QTLs through marker assisted selection in wheat breeding programmes.
Authors:Hoda Mansour, Sahar Shoman, and M. Kdodier
Five cyanophyte species (Amorphonostoc punctiforme, Gloeocapsa turgidus, Sphaeronostoc coeruleum, Stratonostoc linckia f. spongiaeforme and Synechococcus cedrorum) were isolated and identified from sandy Egyptian soils. Polysaccharides extracted from these species showed a pronounced antiviral activity against Rabies and Herpes-1 viruses represented by the absence of the characteristic cytopathic effects of these viruses. It was found that 100 μg polysaccharide/ml induced 100% inhibition of the two viruses which, depending on the polysaccharide concentration. Both of Gloeocapsa turgidus and Synechococcus cedrorum showed higher antiviral activity against rabies virus than that against herpes-1 virus. Amorphonostoc punctiforme showed nil to weak antiviral activity against both viruses. It was suggested that polysaccharides of such species of cyanophyte react against human and animal viruses. So, it could be concluded that there is a need for further studies to explain the mode of action of these substances on the replication of different viral origins to know how one deals with cyanophyte polysaccharides as antiviral substances in the most suitable and effective manner.
Authors:O.Yu. Shoeva, E.I. Gordeeva, V.S. Arbuzova, and E.K. Khlestkina
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.
Authors:Ágnes Vehovszky, A. Szűcs, Henriette Szabó, Samantha Pitt, and C. J. H. Elliott
., Elliott, C. J. H. (2002) Heterosynaptic modulation by the octopaminergic OC interneurons increases the synaptic outputs of protraction phase interneurons (SO, NIL) in the feeding system of Lymnaea stagnalis. Neuroscience 115 , 483
Authors:T. Efremova, V. Arbuzova, I. Leonova, and K. Makhmudova
Two intervarietal substitution lines of common wheat cv. Sava bearing chromosome 5B from Saratovskaya 29 and Diamant 2 donors and two near-isogenic lines (NILs) of winter cv. Bezostaya 1 with the Vrn-B1 locus from the same donors were developed. Multiple allelism of the dominant Vrn-B1 locus was studied in these lines. It manifested itself as earing time variation in plants grown near Novosibirsk (West Siberia), Almaty (Kazakhstan), and in a greenhouse. One dominant allele, Vrn-B1S, having a stronger effect on earing time, was detected in Saratovskaya 29 and another, Vrn-B1Dm, in Diamant 2. The NILs and substitution lines are late-ripening. Lines with Vrn-B1S come to earing earlier than with Vrn-B1Dm.
Authors:S. Rathi, A. Baruah, R. Chowdhury, and R. Sarma
Quantitative Trait Loci (QTL) analyses were conducted in a mapping population of 91 F2 plants derived from a cross between two ahu rice cultivars of Assam, Cheni ahu (dormant, Oryza sativa ssp. indica) and Kolong (non-dormant, Oryza sativa ssp. indica) in order to identify genomic regions affecting seed dormancy and the duration of dormancy. The linkage map based on 70 simple sequence repeat (SSR) markers detected two QTLs for seed dormancy (qSD5, qSD11) and one QTL for duration of dormancy (qSDD5), and came from the dormant parent. The levels of dormancy increased with the presence of any one of the QTLs but qSD5 had larger effect on increasing dormancy, indicating that dormancy could be effectively enhanced by more than one QTL. The QTLs detected could be used to develop near-isogenic lines (NILs) for map-based cloning of seed dormancy in rice, thus to improve the understanding of dormancy of indica rice.
Nine wheat genotypes differing by Rc (red coleoptile) alleles were investigated for the dynamics of seedling growth and relative anthocyanin content in the coleoptiles in response to cold. The stressed genotypes showed either reduced, similar or increased anthocyanin content compared to unstressed plants. This difference can be partially explained by the allelic state of the Rc genes. In ‘Saratovskaya 29’ weak Rc allele causes low anthocyanin content under optimal growth conditions. Upon cold treatment the level of anthocyanins decreased, whereas it increased in two near isogenic lines (NILs) with strong Rc alleles developed on ‘Saratovskaya 29’, and in some other genotypes having high anthocyanin content under optimal growth conditions. The changes in anthocyanin content correlated negatively with the changes of growth parameters in response to cold stress, suggesting the presence of some stress-dependent regulation of anthocyanin biosynthesis in wheat coleoptiles.
A U.K. field experiment compared a complete factorial combination of three backgrounds (cvs Mercia, Maris Huntsman and Maris Widgeon), three alleles at the Rht-B1 locus as Near Isogenic Lines (NILs: rht-B1a (tall), Rht-B1b (semi-dwarf), Rht-B1c (severe dwarf)) and four nitrogen (N) fertilizer application rates (0, 100, 200 and 350 kg N/ha). Linear+exponential functions were fitted to grain yield (GY) and nitrogen-use efficiency (NUE; GY/available N) responses to N rate. Averaged over N rate and background Rht-B1b conferred significantly (P < 0.05) greater GY, NUE, N uptake efficiency (NUpE; N in above ground crop / available N) and N utilization efficiency (NUtEg; GY/N in above ground crop) compared with rht-B1a and Rht-B1c. However the economically optimal N rate (Nopt) for N:grain price ratios of 3.5:1 to 10:1 were also greater for Rht-B1b, and because NUE, NUpE and NUtE all declined with N rate, Rht-Blb failed to increase NUE or its components at Nopt. The adoption of semi-dwarf lines in temperate and humid regions, and the greater N rates that such adoption justifies economically, greatly increases land-use efficiency but not necessarily NUE.