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The root tissues play important roles in water and nutrient acquisition, environmental adaptation, and plant development. In this study, a diversity panel of 388 wheat accessions was collected to investigate nine root system architecture (RSA) traits at the three-leaf stage under two growing environments: outdoor pot culture (OPC) and indoor pot culture (IPC). Phenotypic analysis revealed that root development was faster under OPC than that under IPC and a significant correlation was observed between the nine RSA traits. The 660K single-nucleotide polymorphism (SNP) chip was used for a genome-wide association study (GWAS). Significant SNPs with a threshold of −log10 (p-value) ≥ 4 were considered. Thus, 36 quantitative trait loci (QTLs), including 13 QTL clusters that were associated with more than one trait, were detected, and 31 QTLs were first identified. The QTL clusters on chromosomes 3D and 5B were associated with four and five RSA traits, respectively. Two candidate genes, TraesCS2A01G516200 and TraesCS7B01G036900, were found to be associated with more than one RSA trait using haplotype analysis, and preferentially expressed in the root tissues. These favourable alleles for RSA traits identified in this study may be useful to optimise the root system in wheat.

In recent years, wheat (Triticum aestivum L.) yields have declined as a result of heavy metal pollution. In this study, hydroponics experiments were conducted to assess the genotypic differences in copper (Cu) tolerance and glutathione metabolism in wheat. Thirty-seven wheat cultivars from different primary cultivation areas in China were selected and exposed to Cu stress for 48 h. Six growth and physiological indexes in the young roots were measured, and a comprehensive evaluation of the resistance of wheat to Cu was achieved using correlation analysis, subordinate function analysis, and the median clustering method. Based on the average subordinate function values, the 37 wheat cultivars could be classified into a high Cu-resistant, medium Cu-resistant, and sensitive group. The root transcriptome of ‘Jimai 22’ (high Cu-resistant) and ‘Luomai 23’ (sensitive) under Cu stress was further sequenced using lllumina sequencing technology. The results showed that a total of 49,611 and 43,195 genes were discovered in Jimai 22 and Luomai 23, respectively, in response to Cu. Gene Ontology term enrichment combined with pathway analysis indicated that 26 overrepresented up-regulated DEGs were associated with glutathione metabolism in Jimai 22, while 17 DEGs associated with glutathione metabolism were identified in Luomai 23. Eight of the 13 unique DEGs in Jimai 22 encoded glutathione S-transferases (GST). In addition, the activity of enzymes, including glutathione reductase (GR), glutathione-S-transferase (GST) and ascorbate peroxidase (APX) were measured in the roots. Furthermore, the contents of ascorbate (ASC), reduced glutathione (GSH), oxidized glutathione (GSSG), and some nutrients, including Cu, potassium, calcium, magnesium, sodium, manganese, and zinc, were also determined. The results clearly indicated that excess Cu affected the concentrations of non-enzymatic antioxidants and nutrients (except for Cu). Besides that, APX activity in wheat was affected by excess Cu and it was higher in Jimai 22. On the contrary, GST and GR activity increased with Cu stress treatment for 48 h.

Bread wheat is one of the most important crops in the world. However, osmotic stress significantly inhibits wheat growth and development, and reduces crop yield and quality. Plants respond to osmotic stress mainly through abscisic acid (ABA)-dependent and -independent pathways. In this study, root transcriptome profiles of wheat seedlings exposed to osmotic stress and exogenous ABA were analysed to identify osmotic-responsive genes belonging to the ABA-dependent or -independent pathways. We found that osmotic stress promoted proline biosynthesis in the ABA-dependent pathway, and trehalose biosynthesis is likely promoted among soluble sugars to maintain protein bioactivity under osmotic stress. In wheat roots subjected to osmotic stress, calcium ions, and glutathione exert their functions mainly through calcium-binding protein (CaM/CML) and glutathione-S-transferase, respectively, depending on both pathways. In addition, a complex relationship among phytohormones signal transduction was observed in response to osmotic stress. The findings of this study deepen our understanding of the molecular mechanisms of osmotic-stress resistance, and provide several candidate osmotic-responsive genes for further study.

The study explored the effects of supplementing 0, 200, 400 and 800 mg/kg Zn in cultivating soils on the growth and yield characters of winter wheat Zhoumai 18 and Aikang 58, the two popular wheat varieties currently in Henan, China, planted in pots in a screen house after anthesis during 2009-2010. The results indicated that the differences in activities of Peroxidase (POD), Superoxide Dismutase (SOD) and Catalase (CAT) in flag leaf and grains at 5 and 25 days after anthesis mainly came from differences in Zn concentration, not varieties. In addition, the Photosynthetic rates (Pn) of flag leaf in the two varieties were the same. Zn treatment significantly influenced CAT activity and Pn of flag leaf at 5 days after anthesis, SOD activity in flag leaf at 25 days after anthesis, SOD activity in grains at 5 days after anthesis, as well as POD and CAT activities in grains at 25 days after anthesis (p

This study was to investigate the effect of exogenous nitric oxide (NO) on fructan accumulation and fructan biosynthesic enzymes (FBEs) expression in seedlings leaves of two wheat (Triticum aestivum L.) cultivars, winter wheat (Zhoumai18, ZM) and spring wheat (Yanzhan4110, YZ), under 4 °C. The seedlings of two wheat cultivars were subjected to different concentrations of sodium nitroprussiate (SNP) for 0, 24, 48, and 96 h. Relative water content (RWC) was increased by exogenous NO in YZ, but decreased in ZM. Except for glucose, fructose and fructans of degree of polymerization (DP) 3 in YZ, other soluble carbohydrates contents in the two wheat cultivars all increased to different degrees. The activities of FS (including sucrose: sucrose 1-fructosyltransferase (1-SST, EC: 2.4.1.99) and sucrose: fructan 6-fructosyltransferase (6-SFT, EC: 2.4.1.10)) were significantly higher than fructan: fructan 1-fructosyltransferase (1-FFT, EC: 2.4.1.100) in the seedlings of two wheat cultivars. The same phenomenon occurred to FBEs expression. In addition, sucrose content decreased while fructans content increased under low temperature, which was in accordance with the improved 1-FFT activity in ZM. Moreover, fructans content increased to a high level under high concentration of NO in ZM while kept at a constant low level in YZ. The expression levels of FBEs were universally higher in ZM than in YZ, which identified with the high frost resistance of the winter cultivar. It is concluded that exogenous NO treatment on wheat may be a good option to reduce chilling injury by regulating fructan accumulation in leaves. This is the first report owing that exogenous NO alleviated the negative effects of chilling stress by accumulating fructans in wheat.

Wheat is one of the most important crops in the world. So the safety of wheat product is essential to people's health. With imitating experiment of arsenic polluted soil in pots, effects of nitrogen and phosphorus fertilizers on yield and quality characters of wheat were studied, and arsenic contents of wheat root, stem, grain and soil were determined detailedly. The effective measures by adding nitrogen and phosphorus fertilizers against toxicity of arsenic were emphatically discussed in the paper. The result showed that nitrogen and phosphorus fertilizers improved wheat yield and promoted wheat protein contents to some extent. Arsenic content of grains in mature period was reduced obviously, but the arsenic content of soil, root and stem changed differently, up or down. On the other hand, protein content of wheat grain increased, but contents of protein components, including albumin, globulin, gliadin and glutenin, hardly varied. That is to say, nitrogen and phosphorus fertilizers had no contribution to contents of protein components in wheat grain.

The DNA damage and subcellular of copper (Cu) in 8-day-exposure winter wheat (Triticum aestivum L.) were studied to determine Cu genotoxicity mechanisms and compartmentalization. The results showed Cu induced DNA damage significantly in all treated plants, roots are more cytotoxic and genotoxic than shoots. The translocation factors (ratio of Cu concentrations in shoots to those in roots) were from 0.1 to 0.24 with different Cu treatment. Cu concentrations in the different subcellular fractions increased in shoots and roots with the increase of exogenous Cu. Cu was mostly bound to the cell wall of roots while litter Cu was found in the Cell organelle fraction. Further more, excess Cu inhabited the absorption of many nutrition elements such as K, Ca, Mn, Zn and B in wheat seedlings.