Differential expression of resistance to powdery mildew at the early stage of development in wheat line N0308.

Powdery mildew, caused by Blumeria graminis f. sp tritici (Bgt) is one of the devastating diseases of wheat and causes yield losses in temperate wheat growing regions. A wheat line, N0308 with resistance to powdery mildew was used in this study. A suppression subtractive hybridization cDNA library was constructed from the wheat leaves inoculated by Bgt at the two-leaf stage. The differentially expressed genes in response to Bgt infection in wheat were identified, and a total of 175 positive clones from the library were sequenced, and 90 expressed sequence tags (ESTs) were subjected to clustering, BLAST alignment, functional annotation, and classification into different categories. By comparing the EST sequences among the SSH-cDNA libraries, we analyzed gene expression patterns of 7 ESTs associated with the resistance reaction of powdery mildew by using semi-quantitative reverse transcription-polymerase chain reaction. The expression of 5 genes (sulfatase, pathogenesis-related protein 17, betacarbonic anhydrase 2, thioredoxin h-like protein, and coronatine-insensitive) transcripts was induced, and the transcript levels of these genes were the highest at 72 h after Bgt infection, while those of 2 genes (violaxanthin de-epoxidase and gag-pol-polyprotein) were the highest level at 12 and 18 h post-infection, respectively. These findings suggest that these genes are induced at an early stage of infection and are transcriptionally activated for the host defense response.

Molecular mapping of resistance gene to English grain aphid (Sitobion avenae F.) in Triticum durum wheat line C273.

The English grain aphid, Sitobion avenae (Fabricius), is one of the most important insect pests causing substantial yield losses in wheat production in China and other grain-growing areas in the world. The efficient utilization of wheat genes for resistance to English grain aphid (EGA) provides an efficient, economic and environmentally sound approach to reduce the yield losses. In the present study, the wheat line C273 (Triticum durum AABB, 2n = 4x = 28), is resistant to EGA in greenhouse and field tests. To identify the resistance gene, designated RA-1 temporarily, C273 was crossed with susceptible genotype Poland 305 (T. polonicum, AABB, 2n = 4x = 28). The F(1), F(2) and F(2:3) lines were tested with EGA in the field and greenhouse. The results indicated that RA-1 is a single dominant gene, closely linked to the microsatellite markers (SSR) Xwmc179, Xwmc553 and Xwmc201 on chromosome 6AL at genetic distances of 3.47, 4.73 and 7.57 cM, respectively. The three SSR markers will be valuable in marker-assisted selection for resistance to EGA as well as for cloning this gene in the future.

Genetic characterization of cysteine-rich type-b avenin-like protein coding genes in common wheat.

The wheat avenin-like proteins (ALP) are considered atypical gluten constituents and have shown positive effects on dough properties revealed using a transgenic approach. However, to date the genetic architecture of ALP genes is unclear, making it impossible to be utilized in wheat breeding. In the current study, three genes of type-b ALPs were identified and mapped to chromosomes 7AS, 4AL and 7DS. The coding gene sequence of both TaALP-7A and TaALP-7D was 855 bp long, encoding two identical homologous 284 amino acid long proteins. TaALP-4A was 858 bp long, encoding a 285 amino acid protein variant. Three alleles were identified for TaALP-7A and four for TaALP-4A. TaALP-7A alleles were of two types: type-1, which includes TaALP-7A1 andTaALP-7A2, encodes mature proteins, while type-2, represented byTaALP-7A3, contains a stop codon in the coding region and thus does not encode a mature protein. Dough quality testing of 102 wheat cultivars established a highly significant association of the type-1 TaALP-7A allele with better wheat processing quality. This allelic effects were confirmed among a range of commercial wheat cultivars. Our research makes the ALP be the first of such genetic variation source that can be readily utilized in wheat breeding.

[Purification and biochemical characterization of high-molecular-weight-glutenin subunits 14 and 15].

The high molecular weight glutenin subunits 14 and 15 were purified from cultivars of bread wheat (Triticum aestivum) Xiaoyan 6 by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) appled a new method for visualizing protein in gels. N-terminal amino acid sequences were homologous comparing with other High-Molecular-Weight glutenin subunits. The result suggested that they were basic protein analyzed by two-dimensional electrophoresis of IEF(Isoelectric Focussing) x SDS-PAGE and NEPHGE(Non-Equilibrium PI-gradient Electrophoresis) x SDS-PAGE.

[Effect of somatostatin and GABA on long-term potentiation in hippocampal CA1 are in rats].

UNLABELLED: AIM. To study the effect of somatostatin (SS) and GABA on the long-term potentiation (LTP) of hippocampal CA1 area in rats. METHODS: Active avoidance response (AAR) of shuttle-box was recorded and population spikes (PS) were taken as indices of LTP. RESULTS: Increased percentages of PSA (PS amplitude, in AAR-acquired rats are more than 100%; After intrahippocampal injection (i.h.) of SS (1 g L-1), increased percentages of PSA exhibited above 120%. Increased percentages of PSA were significantly decreased (< 10%, n = 3) and even caused no PS (n = 8) by ih cysteamine (Cys, 20 g L-1, the depletor of SS); i.h. GABA (200 g L-1) indicated that the increased percentages of PSA are less than 30%, GABA weakened the effect of SS on LTP. CONCLUSION: SS enhance hippocampal LTP but GABA decrease it; they may influence each other to regulate the hippocampal synaptic transmission in the process of learning and memory.