Acta Agronomica Sinica最新文献

DREB (dehydration responsive element binding protein) transcription factors play important roles in stress response and regulation of plant growth and development. In general, the traditional method of DNase I foot-printing is used to identify DNA binding of transcription factor. The DNA probes were labeled with isotope and then polyacrylamide gel electrophoresis was performed to separately digested labeled-DNA fragments, which had low resolution ratio and complexity in operation, and was not suitable for detecting interactions in large scales. To explore the transcriptional regulation mechanism of GmDREB3, the DNase I foot-printing method was improved. Combing with electrophoretic mobility shift assay (EMSA), DNA was labeled by fluorescence instead of isotope and the capillary electrophoresis instead of polyacrylamide gel electrophoresis was used to detect the digested DNA fragments and further identify DNA binding region of GmMYB1 in promoter of GmDREB3 gene. DNA binding site of GmMYB1 in GmDREB3 promoter was confirmed via the method of restriction enzyme digesting DNA. To further confirm binding element in GmDREB3 promoter, we used a putative DNA binding element of GmMYB1 to complete EMSA, indicating that GmMYB1 can bind target DNA element in vitro. In short, compared with classic DNase I foot-printing, the modified method is more rapid, accurate and reliable, and will be a high throughput method to identify interactions between proteins and target DNA sites.

ARC1 and EXO70A1 are important signal elements of self-incompatibility in Brassica. To characterize the interaction of ARC1-EXO70A1 during the course of self-incompatibility, the coding sequences of ARC1 and EXO70A1 were cloned from Brassica napus L. and B. oleracea L. var.acephala. Sequence analysis showed that ARC1 consisted of 663 amino acids in B. oleracea and 661 amino acids in B. napus, with a 45-amino-acid difference between them. Sequence alignment showed 95.9% similarity, with 93.9% exact match between BoARC1 and BnARC1. Only a 6-amino-acid difference was detected between BoEXO70A1 and BnEXO70A1, with 99.4% similarity and 98.9% exact match according to further sequence alignment. The homology between EXO70A1 alleles was higher than that between ARC1 alleles. Yeast 2-hybrid results indicated that a strong interaction existed between ARC1 and EXO70A1, which could activate the expressions of 4 reporter genes (ADE2, HIS3, AUR1-C, and MEL1) in diploid yeast. However, there was very weak interaction between EXO70A1 and a 316-C-terminal-deletion mutant of ARC1 (ARC1_N), which only activated the expressions from 3 reporter genes (ADE2, AUR1-C, and MEL1). This indicated that the interaction interface between ARC1 and EXO70A1 might not reside within the Armadillo (ARM) repeat domains of ARC1. The N-terminal domains of ARC1 play an essential role in the interaction of ARC1 with EXO70A1. The influence of the differences in amino-acid composition between BoARC1 and BnARC1 on the interaction between ARC1-EXO70A1 was not detected with a yeast 2-hybrid system, which may indicate that the binding interface between ARC1 and EXO70A1 was not altered by sequence differences between the 2 proteins in these Brassica species.

Wheat (Triticum aestivum L.) cultivar Zhongliang 21 displays resistance to 7 prevalent Puccinia striiformis f. sp. tritici (Pst) races from China. The resistance gene(s) carried by this cultivar was identified using molecular markers in combination with phenotypic evaluation. Seedlings of the F₁, F₂, and BC₁ generations from the cross between Zhongliang 21 (resistant) and Mingxian 169 (susceptible), as well as the parents, were inoculated with Pst race CYR30 in greenhouse, and the resistance was evaluated 15-16 d after inoculation. The results showed that the stripe rust resistance in Zhongliang 21 was conferred by a single dominant gene, which was designated tentatively Yrzhong21. Based on bulked segregant analysis, 10 simple sequence repeat (SSR) markers located on chromosome 5AL were identified to be linked to Yrzhong21, of which Xgwm186 andXbarc165 were the closest flanking markers with genetic distances of 7.4 and 2.7 cM, respectively. In combination with analyses of chromosomal location, reactions to various pathotypes, and pedigree, Yrzhong21 was deduced as a novel gene resistant to stripe rust. Eighteen wheat cultivars (lines) in Zhongliang series were further screened with markers Xgwm186 andXbarc165. Only 3 cultivars produced identical banding pattern to that of Zhongliang 21. This result primarily indicates that only 17% of Zhongliang cultivars (lines) might carry Yrzhong21. This resistance gene is promising in wheat breeding programs for strip rust resistance.

Pigeonpea [Cajanus cajan (L.) Millspaugh] is the only shrubby food legume crop with drought tolerance in the world. Insect pollinators are essential to flower pollination in cytoplasmic genetic male sterility (CGMS) pigeonpea lines, and the species, abundance, and visiting frequency of insect pollinators are the key factors for pigeonpea hybrid production. More than 46 species of insects have been reported to be flower visitors in the open field for pigeonpea production outside China, of which Megachile spp. are the major pollinators. In this study, the species, abundance, and visiting frequency of flower-visiting insects at flowering stage, as well as hybrid yield of pigeonpea, were investigated in the pigeonpea hybrid production field in Yuanmou County, Yunnan Province, China, using CGMS-based ICPH2671 hybrid. A total of 25 species of flower-visiting insects were detected, including 5 major pollinator species, Megachile velutina Sm., Megachile sp-5, Xylocopa tenuiscapa Westw., Apinae sp-1, and Megachile sp-2. At the blooming stage, the flower-visiting insects visited each primary branch at a frequency of 2.8 times per 10 min for the CGMS male sterile line, while at a frequency of 5.2 times per 10 min for the CGMS restorer line. This indicated the preference of flower-visiting insects to the flowers of restorer line. This significant difference between the male sterile and the restorer lines resulted in very similar dry seed yields of the male sterile line (383.7 g per plant) and the restorer line (357.0 g per plant). Therefore, enough pollens can been transported from the restorer line to the male sterile line by insect pollinators, even much less visiting frequency on the flowers of male sterile line compared to that of the restorer line.

The objectives of this study were to study the effect of cadmium (Cd) stress on peanut (Arachis hypogaea L.) growth and kernel yield and quality, and provide a guide for the safe production of peanut. In the pot experiments carried out in 2009 and 2010, 2 cultivars, Yuhua 15 and XB023, were cultured under light (1.0 mg kg⁻¹), medium (2.5 mg kg⁻¹), heavy (7.5 mg kg⁻¹), and high (15.0 mg kg⁻¹) Cd stress. No Cd stresses treatment was used as the control. The vegetative growth of peanut plants were stimulated under light and medium Cd conditions, but depressed under heavy and high Cd conditions. The chlorophyll contents and photosynthetic rates of leaves of Yuhua 15 decreased with the increase of Cd concentrations. The chlorophyll contents of XB023 were increased under light and medium Cd stresses and decreased under heavy and high Cd stresses, while photosynthetic rates of leaves of XB023 decreased with the increase of Cd concentrations. The sensitivities of yield to Cd stress were different in the 2 cultivars. Yuhua 15 were more sensitive to Cd stress than XB023, because yield per pot, kernel weight per pot, kernel rate per pod, and pod number per plant in Yuhua 15 were significantly reduced under medium or higher Cd concentrations, while those in XB023 were significantly reduced under heavy and high Cd concentrations. The influence of Cd stress on seed quality also had genotypic interaction. In Yuhua 15, Cd stress increased the content of soluble sugar and decreased the contents of protein and oil, as well as the ratio of oleic-acid-to-linoleic-acid (O/L); in XB023, Cd stress decreased the contents of soluble sugar and oil and O/L ratio, and light and medium Cd stresses increased the contents of protein and its components of Lys and Thr in peanut kernels. In both cultivars, the Cd contents in kernel were higher than that in the control. Yuhua 15 had higher Cd content in plant and lower Cd content in kernel than XB 023.

Two rice varieties with similar apparent amylose content, Nipponbare (Oryza sativa subsp. japonica) and 93-11 (O. sativa supbsp. indica), were used as parents to establish a recombinant inbred line population consisting of 190 lines by single seed descent method. The genetic linkage map contained 202 simple sequence repeat (SSR), cleaved-amplified polymorphism sequence (CAPS), and sequence tagged site (STS) markers. Quantitative trait loci (QTLs) were identified for 8 rice starch RVA profile properties including peak paste viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV), breakdown viscosity (BDV), setback viscosity (SBV), consistence viscosity (CSV), peak time (PeT), and pasting temperature (PaT) in 3 ecological sites using composite interval mapping method. A total of 57 QTLs were identified, with 1 to 14 for each trait. Thirteen stable QTLs were detected at repeated environments, among which qCPV-3, qCPV-10b, qSBV-10b, qCSV-3b, and qCSV-10b were detected in all environments, and they explained 26.9%, 29.5%, 29.7%, 25.2%, and 28.3% of phenotypic variations, respectively. Sixteen QTLs had pleiotropy with a single QTL controlling 2–6 RVA profile properties. The interval of RM25032-RM1375 on chromosome 10 harbored gene loci controlling PKV, HPV, CPV, SBV, PaT, and CSV.