Characterization of chromosome segment substitution lines reveals candidate genes associated with the nodule number in soybean

Soybean is one of the most important food crops worldwide. Like other legumes, soybean can form symbiotic relationships with Rhizobium species. Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for sustainable agriculture. Type III effectors(T3Es) are essential regulators of the establishment of the symbiosis, and nodule number is a feature of nitrogen-affected nodulation. However, genes encoding T3Es at quantitative trait loci(QTLs) related to nodulation have rarely been ...     

Effects of Several Metals on Both Fe(III)‐ and Cu(II)‐Reduction by Roots of Fe‐Deficient Cucumber Plants

Abstract

The ferric‐chelate reductase induced by Fe deficiency is also able to reduce other ions such as Cu²⁺. This Cu(II)‐reduction has been less studied and it has been suggested that Cu²⁺ ion rather than Cu²⁺‐chelate serves as the substrate. Ferric‐chelate reductase activity is inhibited by some metals, but the mechanisms implicated are not known. In the present work we use Fe‐deficient cucumber seedlings to study the interactions of Cu²⁺, Ni²⁺, Mn⁴⁺, and Fe³⁺ on both Fe(III)‐reduction and Cu(II)‐reduction activities. The response of Cu(II)‐reduction activity to Cu concentration, in the presence or absence of citrate, was also studied. Results showed that inhibition of the ferric‐chelate reductase activity by Cu²⁺ or Ni²⁺ could be partially reversed by increasing the concentration of Fe‐EDTA. The Cu(II)‐reduction activity was even stimulated by Fe‐EDTA or Ni²⁺; it was inhibited by a high concentration of Cu²⁺ itself; and it was not affected by the absence of citrate. Mn⁴⁺ caused a moderate inhibition of both Fe(III)‐reduction and Cu(II)‐reduction activities. Results agree with the hypothesis that free Cu²⁺ ion is the substrate for Cu(II)‐reduction and suggest that the mechanisms involved in Fe(III)‐reduction and Cu(II)‐reduction could have some differences and be affected by metals in different ways. The mode of action of metals on the reductase activity are discussed, but they are still not well known.     

Genetic structure analysis of strains causing citrus canker in Iran reveals the presence of two different lineages of Xanthomonas citri pv. citri pathotype A*

West Asia has been recognized as a major centre for the diversification of Xanthomonas citri pv. citri, a citrus quarantine pathogen of considerable economic importance. However, little genotyping data is available mainly due to the paucity of microbial resources in this region. Using a comprehensive strain collection, several genotyping techniques and a pathogenicity assay, the status of strains causing Asiatic citrus canker in Iran, an internationally significant citrus‐producing country, was clarified. All strains were genetically related to X. citri pv. citri pathotype A* (i.e. strains with a host range restricted to Mexican lime and related species) but not to pathotype A (i.e. strains with a wide host range among rutaceous species). The findings were based on discriminant analysis of the principal components of MLVA‐31 data and were further confirmed by pathogenicity data. Two genetically, geographically and pathologically separate groups of strains in Iran were identified. One of the groups had never been previously reported anywhere in the world. A very strong genetic structure was found (R_ST = 0·938), consistent with their geographical isolation. Strains from these two groups also differed in terms of their type III effector repertoire. The atypical host range of one of these groups could explain why some Iranian strains had previously been mistakenly identified as pathotype A. This study suggests the absence of invasive pathotype A strains in Iran (known as DAPC 1), which account for most of the economically important outbreaks internationally.     

闹羊花素-III对菜青虫神经系统的影响

以闹羊花素 - III处理 5龄菜青虫幼虫 ,试虫乙酰胆碱酯酶 (ACh E)的活体活性和离体活性均与对照无明显差异 ,乙酰胆碱 (ACh)含量显著降低 ;对 Na - K - ATP酶、Ca2 -Mg2 - ATP酶比活力有可逆性激活作用 ,处理后 2 4 h比活力提高 ,尤以低剂量 1μg·虫 -1处理的比活力显著提高 ;处理后 6 0 h,以 1～ 3μg·虫 -1处理的比活力恢复正常 ,以 5～ 10μg·虫 -1处理的比活力显著低于对照。     

Production of specific dsRNA against white spot syndrome virus in the yeast Yarrowia lipolytica

White spot syndrome virus (WSSV) is the most aggressive disease affecting cultured shrimp. One possibility to tackle it is by means of RNA interference (RNAi) induced by the presence of double‐stranded RNA (dsRNA). Normally, dsRNA is a product of the cellular machinery to gene regulation, but it can be produced synthetically and introduced into specific tissues or cells and thereby induce RNAi. Although in vitro production of dsRNA is possible, this is high cost. An alternative is to produce dsRNA in vivo using biological systems such as bacteria or yeasts. In this regard, Yarrowia lipolytica offers distinctive advantages for dsRNA production. The objective was to develop a Y. lipolytica strain able to produce dsRNA‐specific against WSSV and to evaluate its antiviral activity in the white leg shrimp Litopenaeus vannamei. From the 0.4 and 0.6 Kb fragments of the ORF89 gene, a dsRNA‐ORF89‐producing construct was built in the plasmid pJC410; the resulting construct (pARY410) was used to transform Y. lipolytica to drive the specific expression of dsRNA‐ORF89. Yeast colonies positive to the WSSV‐ORF89 gene were selected. The expression of dsRNA‐ORF89 and RNAse III was measured being detected at 32 and 48 hr. Subsequently, the antiviral activity of dsRNA‐ORF89 was tested in a WSSV challenge bioassay. The results showed survival in dsRNA‐ORF89 shrimp (25%) compared to control organisms treated with total RNA from the yeast P01‐AS harvested at 32 hr. In conclusion, Y. lipolytica is a convenient host to produce and deliver dsRNA‐ORF89 able to protect WSSV‐challenged shrimp.     

Alteration of haemostatic parameters in uncomplicated canine babesiosis

Babesiosis is a tick-borne zoonotic disease caused by haemoprotozoan parasites. The aim of this study were to assess markers of coagulation pathways in 25 dogs with naturally occurring babesiosis caused by B. canis, compared to 10 healthy controls. Protein C (PC) and antithrombin III (AT III) activity were assessed using a chromogenic substrate test, while levels of thrombin-antithrombin (TAT) complexes, activated protein C (APC) and endothelial protein C receptor were assessed using canine-specific ELISA. AT III activity was decreased as a result of a negative acute phase response, degradation by elastase, reduced availability of glycosaminoglycans, and, most importantly, consumption as a consequence of thrombin formation. Procoagulant state and haemostatic shift towards thrombin formation are also demonstrated by elevated TAT levels. Regarding PC pathway only significant difference was found for APC. Taken together, haemostatic alterations in uncomplicated babesiosis represent a procoagulant state that is mostly reversed during treatment.     

粳型杂交水稻新组合Ⅲ优98的亲本特性及制种技术研究

根据Ⅲ优98亲本的特征特性,经过多年的深入研究和制种实践,总结出了该组合的优质高产制种技术。     

Genetic Polymorphism of Kappa Casein （K-CN）in Iraqi Buffalo Using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism

This study was carried out the animal production department, genetic engineering lab, college of agriculture, （UoB）, Iraq. The aim of this study was to use the polymerase chain reaction restriction fragment length polymorphism （PCR-RFLP） as a fast, efficient and low cost method to detect the genetic variants of kappa-casein gene （k-CN） in Iraqi buffalo using three different primers specific for bovine k-CN to amplify the gene segment, followed by digestion using restriction enzyme （Hind III） for genotyping. DNA from 50 Iraqi buffaloes was extracted by phenol chloroform method. PCR was carried out in a final reaction volume of 25 μL and the reaction mixture was subjected to standard PCR protocol. The results of this work show that among the examined 50 Iraqi Buffalo were homozygous for the K-CN and genotyped as BB for all three primers but gave different bands. Thus PCR-RFLP using Hind III revealed all the samples to be monomorphic for this locus. The restriction digestion analysis of 397 bp PCR product of k-CN indicates the presence of two fragments of 154 bp and 225 bp for BB-genotype. A 437 bp fragment of the bovine genomic K-CN gene was amplified. One Hind III restriction site is found in position 346 of the amplified fragment of allele k-CN B, yielded 91 bp and 346 bp. Amplified products from Iraqi buffalo （530）, after being digested with Hind III, yielded two separate DNA fragments of different sizes i.e., 160 bp and 370 bp. For the first time completed research such specifications in Iraq, for the first time using molecular biology in genetic identification. Our objectives of this study have been to aid in understanding domestication, Buffalo origin and their history and evolution, to identify genetically unique breeds, to provide an objective basis for conservation decisions and to aid the formulation of breeding plans.