Authors:L. Liu, Z. He, W. Ma, J. Liu, X. Xia, and R. Peña
Glutenin subunit alleles at the
locus and their effects on dough properties, pan bread, and dry white Chinese noodle (DWCN) qualities were investigated using 106 winter and facultative wheat cultivars and advanced lines. Allele
(42.5%) was the most frequent glutenin subunit, followed by
occurred in only three and six cultivars, respectively. The effect of
was significant forDWCNquality, accounting for up to 16% of the variation, but there were no significant differences between individual
alleles on dough properties and qualities of DWCNand pan bread. Interaction effects
Glu-A1 × Glu-D3
Glu-B1 × Glu-D3
were significant for DWCN quality and loaf volume. More work is needed to understand the effects of
variation on the determination of dough properties and end-use quality.
Authors:S. Tang, L. Li, Q.Y. Zhou, W.Z. Liu, H.X. Zhang, W. Z. Chen, and Y.F. Ding
Gibberellins (GAs) are a class of plant hormones that play important roles in diverse aspects during plant growth and development. A series of GA synthesis and metabolism genes have been reported or proved to have essential functions in different plant species, while a small number of GA 2-oxidase genes have been cloned or reported in wheat. Previous studies have provided some important findings on the process of GA biosynthesis and the enzymes involved in its related pathways. These may facilitate understanding of the complicated process underlying GA synthesis and metabolism in wheat. In this study, GA 2-oxidase genes TaGA2ox1-1, TaGA2ox1-2, TaGA2ox1-3, TaGA2ox1-4, TaGA2ox1-5, and TaGA2ox1-6 were identified and further overexpressed in rice plants to investigate their functions in GA biosynthesis and signaling pathway. Results showed overexpression of GA 2-oxidase genes in rice disrupted the GA metabolic pathways and induced catalytic responses and regulated other GA biosynthesis and signaling pathway genes, which further leading to GA signaling disorders and diversity in phenotypic changes in rice plants.
Authors:Z.L. Li, H.Y. Li, G. Chen, X.J. Liu, C.L. Kou, S.Z. Ning, Z.W. Yuan, M. Hao, D.C. Liu, and L.Q. Zhang
Seven Glu-A1m allelic variants of the Glu-A1mx genes in Triticum monococcum ssp. monococcum, designated as 1Ax2.1a, 1Ax2.1b, 1Ax2.1c, 1Ax2.1d, 1Ax2.1e, 1Ax2.1f, and 1Ax2.1g were characterized. Their authenticity was confirmed by successful expression of the coding regions in E. coli, and except for the 1Ax2.1a with the presence of internal stop codons at position of 313 aa, all correspond to the subunit in seeds. However, all the active six genes had a same DNA size although their encoding subunits showed different molecular weight. Our study indicated that amino acid residue substitutions rather than previously frequently reported insertions/deletions played an important role on the subunit evolution of these Glu-A1mx alleles. Since variation in the Glu-A1x locus in common wheat is rare, these novel genes at the Glu-A1mx can be used as candidate genes for further wheat quality improvement.
Authors:Q. Chen, M. Cao, W. Xiang, Q. Sun, J. Zhang, R. Hou, Z. Yan, Z. Yang, J. Liu, and J. Zhao
The forward and reverse cDNA subtractive libraries before and after the toxic effect of α-amanitin were constructed by suppression subtractive hybridization and randomly selected clones from each subtractive library were screened by PCR and dot blot hybridization. A total of 85 genes with altered expression were finally identified, with 41 genes from the forward library and 44 from the reverse library. Subsequently, the antagonistic effects of candidate traditional Chinese medicines were evaluated based on the genetic transcription levels of the genes with significant altered expression, including Catnβ, Flt3-L, IL-7r and Rpo2-4. The results indicated that
(L.) Gaert and
had significant down-regulated effects on the transcription level of Catnβ that was up-regulated by α-amanitin, and the two herbs also up-regulated the transcription levels of Flt3-L and Rpo2-4.
(L.) had significant up-regulated effects on the IL-7r that was down-regulated by α-amanitin. These preliminary studies suggested that
were effective antagonists against the toxicity of α-amanitin.
Authors:N. Li, Z. Yu, L. Wang, Y. Zheng, J. Jia, Q. Wang, M. Zhu, X. Liu, X. Xia, and W. Li
The aim of this study was to investigate the effects of maternal lead exposure on the learning and memory ability and expression of tau protein phosphorylation (P-tau) and beta amyloid protein (Aβ) in hippocampus of mice offspring. Pb exposure initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at the concentrations of 0.1%, 0.5% and 1% groups. On the 21
of postnatal day, the learning and memory ability of the mouse pups was tested by Water Maze test and the Pb levels in blood and hippocampus of the offspring were also determined. The expression of P-tau and Aβ in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than that of the control group (
< 0.05). In Water Maze test, the performances of 0.5% and 1% groups were worse than that of the control group (
< 0.05). The expression of P-tau and Aβ was increased in Pb exposed groups than that of the control group (
< 0.05). Tau hyper-phosphorylation and Aβ increase in the hippocampus of pups may contribute to the impairment of learning and memory associated with maternal Pb exposure.
Authors:X.L. Liu, B.Y. Lu, C.Y. Wang, Y.J. Wang, H. Zhang, Z.R. Tian, and W.Q. Ji
The aphid Sitobion avenae F. is one of the most harmful pests of wheat growth in the world. A primary field screening test was carried out to evaluate the S. avenae resistance of 527 wheat landraces from Shaanxi. The results indicated that 25 accessions (4.74%) were resistant to S. avenae in the three consecutive seasons, of which accession S849 was highly resistant, and seven accessions were moderately resistant. The majority of S. avenae resistant accessions come from Qinling Mountains. Then, the genetic variability of a set of 33 accessions (25 S. avenae resistant and 8 S. avenae susceptible) originating from Qinling Mountains have been assessed by 20 morphological traits and 99 simple sequence repeat markers (SSRs). Morphological traits and SSRs displayed a high level of genetic diversity within 33 accessions. The clustering of the accessions based on morphological traits and SSR markers showed significant discrepancy according to the geographical distribution, resistance to S. avenae and species of accessions. The highly and moderately resistant landrace accessions were collected from the middle and the east part of Qinling Mountains with similar morphology characters, for example slender leaves with wax, lower leaf area, and high ear density. These S. avenae resistant landraces can be used in wheat aphid resistance breeding as valuable resources.
Authors:W.J. Chi, Z.Y. Wang, J.M. Liu, C. Zhang, Y.H. Wu, and Y.J. Bai
Nitrogen (N) is an important nutrient for plant growth and yield production, and rice grown in paddy soil mainly uses ammonium (NH4+) as its N source. Previous studies have shown that N status is tightly connected to plant defense; however, the roles of NH4+ uptake and assimilation in rice sheath blight disease response have not been studied previously. Here, we analyzed the effects of different N sources on plant defense against Rhizoctonia solani. The results indicated that rice plants grown in N-free conditions had higher resistance to sheath blight than those grown under N conditions. In greater detail, rice plants cultured with glutamine as the sole N source were more susceptible to sheath blight disease compared to the groups using NH4+ and nitrate (NO3–) as sole N sources. N deficiency severely inhibited plant growth; therefore, ammonium transporter 1;2 overexpressors (AMT1;2 OXs) were generated to test their growth and defense ability under low N conditions. AMT1;2 OXs increased N use efficiency and exhibited less susceptible symptoms to R. solani and highly induced the expression of PBZ1 compared to the wild-type controls upon infection of R. solani. Furthermore, the glutamine synthetase 1;1 (GS1;1) mutant (gs1;1) was more susceptible to R. solani infection than the wild-type control, and the genetic combination of AMT1;2 OX and gs1;1 revealed that AMT1;2 OX was less susceptible to R. solani and required GS1;1 activity. In addition, cellular NH4+ content was higher in AMT1;2 OX and gs1;1 plants, indicating that NH4+ was not directly controlling plant defense. In conclusion, the present study showed that the activation of NH4+ uptake and assimilation were required for rice resistance against sheath blight disease.
Premature termination codons (PTCs) are an important reason for the silence of highmolecular- weight glutenin subunits in Triticum species. Although the Glu-A1y gene is generally silent in common wheat, we here isolated an expressed Glu-A1y gene containing a PTC, named 1Ay8.3, from Triticum monococcum ssp. monococcum (AmAm, 2n = 2x = 14). Despite the presence of a PTC (TAG) at base pair positions 1879–1881 in the C-terminal coding region, this did not obviously affect 1Ay8.3 expression in seeds. This was demonstrated by the fact that when the PTC TAG of 1Ay8.3 was mutated to the CAG codon, the mutant in Escherichia coli bacterial cells expressed the same subunit as in the seeds. However, in E. coli, 1Ay8.3 containing the PTC expressed a truncated protein with faster electrophoretic mobility than that in seeds, suggesting that PTC translation termination suppression probably occurs in vivo (seeds) but not in vitro (E. coli). This may represent one of only a few reports on the PTC termination suppression phenomenon in genes.
Authors:J.W Guo, Q. Li, W.Q. Chen, X. Li, L.Q. Li, T.G. Liu, Z.L. Ren, and P.G. Luo
Leaf senescence is a notably important trait that limits the yield and biomass accumulation of agronomic crops. Therefore, determining the chromosomal position of the expression sequence tags (ESTs) that are associated with leaf senescence is notably interesting in the manipulation of leaf senescence for crop improvement. A total of 32 ESTs that were previously identified during the delaying leaf senescence stage in the stay-green wheat cultivar CN17 were mapped to 42 chromosomes, a chloroplast, a mitochondrion, and a ribosome using in silico mapping. Then, we developed 19 pairs of primers based on these sequences and used them to determine the polymorphisms between the stay-green cultivars (CN12, CN17, and CN18) and the control cultivar MY11. Among the 19 pairs of primers, 5 pairs produced polymorphisms between the stay-green cultivar and the non-stay-green control. Further studies of Chinese Spring nullisomic-tetrasomics show that JK738991 is mapped to 3B, JK738983 is mapped to 5D, and JK738989 is mapped to 2A, 4A, and 3D. The other two ESTs, JK738994 and JK739003, were not assigned to a chromosome using the Chinese Spring nullisomic-tetrasomics, which indicates that these ESTs may be derived from rye DNA in the wide cross. In particular, the ESTs that produce polymorphisms are notably useful in identifying the stay-green cultivar using molecular marker-assisted selection. The results also suggest that the in silico mapping data, even from a comparison genomic analysis based on the homogeneous comparison, are useful at some points, but the data were not always reliable, which requires further investigation using experimental methods.
Authors:Z. L. Li, D. D. Wu, H. Y. Li, G. Chen, W. G. Cao, S. Z. Ning, D. C. Liu, and L. Q. Zhang
Gliadin is a main component of gluten proteins that affect functional properties of bread making and contributes to the viscous nature of doughs. In this study, thirteen novel ω-gliadin genes were identified in several Triticum species, which encode the ARH-, ATDand ATN-type proteins. Two novel types of ω-gliadins: ATD- and ATN- have not yet been reported. The lengths of 13 sequences were ranged from 927 to 1269 bp and the deduced mature proteins were varied from 309 to 414 residues. All 13 genes were pseudogenes because of the presence of internal stop codons. The primary structure of these ω-gliadin genes included a signal peptide, a conserved N-terminal domain, a repetitive domain and a conserved C-terminus. In this paper, we first characterize ω-gliadin genes from T. timopheevi ssp. timopheevi and T. timopheevi ssp. araraticum. The ω-gliadin gene variation and the evolutionary relationship of ω-gliadin family genes were also discussed.