Comprehensive molecular analysis of arginase-encoding genes in common wheat and its progenitor species.

Arginase (ARG) contributes to nitrogen remobilization by conversion of arginine to ornithine and urea. However, wheat ARG genes have not yet been identified. Here we isolated and characterized ARG genes from wheat and its progenitor species and found that a single copy was present in wheat progenitors. Three common wheat ARG genes of TaARG-2AS, TaARG-2BS, and TaARG-2DS were experimentally assigned to the short arms of the group 2 chromosomes. We found an in-frame stop codon in TaARG-2AS, but not in the other two genes. The highest expression was detected in stems and sheaths for TaARG-2BS and in leaves for TaARG-2DS. Both genes have similar expression trend in different developmental stages, peaking at booting and grain filling stages. TaARG-2BS transcript was induced by high salinity and drought, whereas TaARG-2DS was induced by drought only, but neither of them were induced by low temperature. In addition, both genes showed analogous expression pattern upon powdery mildew (PM) infection in the resistant line Pm97033, with TaARG-2BS induced greatly at 72 h post PM infection. In contrast, no obvious transcripts were accumulated for TaARG-2DS in the PM susceptible line Wan7107. Monocot ARGs have more conserved mitochondrion-targeting signals and are more evolutionarily conserved than dicot ARGs.

Efficient regeneration potential is closely related to auxin exposure time and catalase metabolism during the somatic embryogenesis of immature embryos in Triticum aestivum L.

Regeneration of cultured tissue is a prerequisite of Agrobacterium- and biolistic-mediated plant transformation. In this study, an efficient protocol for improving wheat (Triticum aestivum L.) immature embryo regeneration was developed. Based on the statistical analysis of embryogenic callus induction efficiency, green spot differentiation efficiency, and plant regeneration efficiency from five wheat accessions, improved culture conditions were found to be more effective for embryogenic callus production than the traditional conditions. Using semi-quantitative reverse transcription polymerase chain reaction, a candidate gene, designated as TaCAT1, which encodes a catalase was identified to have a significant correlation with high-regeneration trait of wheat immature embryos. Three amino acid substitutions were found in TaCAT1 protein between high- and low-regeneration wheat accessions. Hydrogen peroxide content in the cultured calli increased from day 5 to 15, and then decreased sharply on day 20, followed by a second peak on day 25 during regeneration stage. Furthermore, a 3,500-bp 5' flanking region upstream of the first codon ATG of TaCAT1 was isolated using inverse polymerase chain reaction. In silico, analysis revealed that the TaCAT1 promoter contained two regulatory motifs associated with responses to auxin.

[Effect of compound Chinese sour taste herbs on advanced glycation end products content and gene expression of their receptors in aorta of rats with type 2 diabetes mellitus].

OBJECTIVE: To investigate the possible mechanism of compound Chinese sour taste herbs (CS) in preventing and ameliorating diabetic macroangiopathy by analyzing the effects of CS on the deposition of advanced glycation end products (AGEs) and gene expression of receptor for advanced glycation end products (RAGE) in the aorta tissue of rats with type 2 diabetes mellitus (T2DM). METHODS: Rat model of T2DM was established by peritoneal injection of streptozotocin (STZ) and high caloric diet feeding. Experimental SD rats were divided into the normal group, the model group, the aminoguanidine (AG) group, and the CS group. At the end of the 8th and 12th week, the fasting blood glucose (FBG) was measured by glucose oxidase method; content of AGEs and collagen in aorta detected by fluorescent method and gene expression of RAGE in aorta determined by Real-time PCR method. RESULTS: FBG, AGEs and collagen contents and RAGE expression in aorta of model rats were all higher than those in the normal control group (P <0.05), while all these indices were lower in the CS group than in the model group (P<0.05). CONCLUSION: CS could realize the goal for preventing and ameliorating diabetic macroangiopathy by way of suppressing the production of AGEs and down-regulating the gene expression of RAGE in aorta of T2DM rats.