Variation in the response of melon genotypes to Fusarium oxysporum f.sp. melonis race 1 determined by inoculation tests and molecular markers

Screening of genotypes of melon ( Cucumis melo ) for resistance to wilt caused by Fusarium oxysporum f.sp. melonis is often characterized by wide variability in their responses to inoculation, even under carefully controlled conditions. The variability at the seedling stage of 17 genotypes susceptible to race 1 was examined in growth-chamber experiments. Disease incidence varied from 0 to 100% in a genotype-dependent manner. Using four combinations of light (60 and 90  µ E m⁻² s⁻¹) and temperatures of (27 and 31°C), only light intensity showed a statistically significant effect. Marker-assisted selection for fusarium resistance breeding using cleaved amplified polymorphic sequence (CAPS) and sequence-characterized amplified region (SCAR) markers were compared using a single set of genotypes that included 24 melon accessions and breeding lines whose genotype regarding the Fom-2 gene was well characterized. The practical value of the markers for discriminating a range of genotypes and clarifying the scoring of phenotypes was also tested using a segregating breeding population which showed codominant SCAR markers to be useful in marker-assisted selection.     

Rapid detection of Phytophthora cinnamomi using PCR with primers derived from the Lpv putative storage protein genes

Phytophthora cinnamomi is an ecologically and economically important pathogen. In this study, PCR assays were developed with primer pair LPV2 or LPV3 for rapid detection and identification of this organism. Both primer pairs were selected from putative storage protein genes. The specificity of these primer pairs was evaluated against 49 isolates of P. cinnamomi , 102 isolates from 30 other Phytophthora spp., 17 isolates from nine Pythium spp. and 43 isolates of other water moulds, bacteria and true fungi. PCR with both primer pairs amplified the DNA from all isolates of P. cinnamomi regardless of origin. The LPV3 primers showed adequate specificity among all other species tested. The LPV2 primers cross-reacted with some species of Pythium and true fungi, but not with any other Phytophthora species. PCR with the LPV3 primers detected the pathogen at levels of a single chlamydospore or 10 zoospores in repeated tests. The PCR assay was at least 10 times more sensitive than the plating method for detection of the pathogen from artificially infested soilless medium, and, to a lesser extent, from naturally infected plants. PCR with LPV3 primers can be a useful tool for detecting P. cinnamomi from soilless media and plant tissues at ornamental nurseries, whereas the LPV2 primers can be an effective alternative for identification of this species from pure culture. Applications of these assays for detection of P. cinnamomi in other environments were also discussed.     

棉铃虫核型多角体病毒分子生物学和基因工程研究进展

棉铃虫核型多角体病毒(HaSNPV)是棉铃虫专一性病原物,隶属于杆状病毒科核型多角体病毒属.对其分子生物学和基因工程的研究主要包括以下几个方面:测定了HaSNPV G4株和C1株基因组核苷酸全序列,并与其它病毒进行了同源性比较;研究了HaSNPV部分基因的结构、转录、表达及其功能.构建了HaSNPV Bac to Bac杆状病毒表达系统;重组病毒杀虫剂的研究为HaSNPV大面积防治棉铃虫展示了广阔的前景.随着棉铃虫核型多角体病毒分子生物学和基因工程研究的不断深入,重组病毒杀虫剂将在棉铃虫综合防治中发挥更为重要的作用.     

Mariner转座子与小菜蛾抗性关系的研究

以抗溴氰菊酯、杀虫双、杀螟丹小菜蛾种群及其敏感品系为研究对象,借助聚合酶链式反应(PCR)、载体筛选、琼脂糖凝胶电泳等实验技术,检测了小菜蛾4个品系的Mariner转座子的存在及其与抗性的关系。结果表明,在抗溴氰菊酯、杀虫双、杀螟丹以及敏感品系的小菜蛾中都存在两种大约500 bp的Mariner转座子片断,初次证明在小菜蛾4个品系中均含有两种Mariner转座子,并发现一种新的转座子基因片断,但是没有发现Mariner转座子与抗性之间存在直接的联系。研究结果将为利用Mariner转座子标签法在小菜蛾中分离定位基因、转化外源基因、转基因昆虫防治害虫等研究提供理论基础。     

新扬州鸡IGF-1基因多态性与早期生长速度关系的研究

以150只非同胞新扬州鸡为材料，采用PCR—RFLP法检测了该基因5’调控区DNA序列多态性，并运用线性模型统计方法分析了多态性与初生重和12周龄体重的关系。结果显示：新扬州鸡IGF-1基因5、调控区自然存在两种不同DNA序列，经。PstⅠ酶切后出现3种基因型(“-／-”、“-／ ”、“ ／ ”)，基因型分布符合哈代一温伯格定律。各基因型个体的初生重、12周龄体重的最小二乘均数存在“-／-”＞“ ／-”＞“ ／ ”的趋势，且“-／-”型个体的12周龄体重显著高于“ ／ ”型个体(P＜0．05)。     

美系杜洛克种猪体尺、体重测定与体型评定研究

统计分析了2001年引进的新美系杜洛克种猪及繁殖后代在6月龄、12月龄、24月龄和36月龄四个阶段的体尺、体重数据，结合品种特征、体型外貌总结研究出杜洛克种猪的百分制评分及等级标准。     

The complete mitochondrial genome and molecular phylogeny of Lueyang black-bone chicken

ABSTRACT

1. The objectives of the current study were to investigate the mitochondrial genome and molecular phylogeny of Lueyang black-bone chicken, and provide molecule base to preserve and explore the specific chicken strain.

2. Based on sequencing and clustering, the complete mitochondrial DNA map and sequences of Lueyang black-bone chicken were revealed, and two phylogenetic trees of Lueyang black-bone chickens based on D-loop sequences and the mitochondrial genome were constructed.

3. The results showed that the complete mitochondrial genome of Lueyang black-bone chickens is 16,784bp in size, consisting of 22 transfer RNA genes, two ribosomal RNA genes, 13 protein-coding genes, and one non-coding control region. The base composition of the complete mtDNA sequence is 30.28% for A, 23.78% for T, 32.42% for C, 13.52% for G. Additionally, 10 haplotypes of D-loop sequences in 32 Lueyang black-bone chickens were detected, which were distributed into 4 clades (A, B, C and E).

4. It was concluded that genetic diversity is wide in Lueyang black-bone chickens, and this strain has multiple maternal origins from different regions in China and neighbouring regions.     

Changes in technical efficiency of the broiler production in Poland, 1994–2013

1. The effects of changes in technical efficiency on the increase of broiler production are presented for the period 1994–2013 based on the panel data from seven farms located in southern and central Poland. A total of 766 cycles were analysed.

2. The Cobb–Douglas production function was used to assess the changes of output elasticities as well as technical changes in broiler production, for 5-year sub-periods separately.

3. Technical indices of broiler production significantly improved between years 1994–2013: feed conversion ratio decreased from 2.50 kg/kg to 1.78 kg/kg, mortality rate from 8.8% to 4.0% and daily weight gain increased from 37.1 g/d to 58.7 g/d, respectively.

4. Before accession to the EU, there was a substantial increase of fixed capital connected with modernisation of buildings and equipment. In the period 1994–2013, inputs of fixed capital per kilogram of livestock increased by 72% and at the same time the input of labour decreased by 56%.

5. Technical changes in years 1994–1998 contributed to a rapid production increase at a rate of 4.6% annually and only by up to 0.7% annually during 2009–2013. The slowdown of production rate increase after 2009 was partially caused by decreasing the stocking density.     

Multimarker and rare variants genomewide association studies for bone weight in Simmental cattle

Bone weight, defined as the total weight of the bones in all the forequarter and hindquarter joints, can reflect somebody conformation traits and skeletal diseases. To gain a better understanding of the genetic determinants of bone weight, we used a composite strategy including multimarker and rare‐marker association to perform genomewide association studies (GWAS) for that character in Simmental cattle. Our strategy consisted of three models: (i) A traditional linear mixed model (LMM) was applied (Q+K‐LMM); (ii) single nucleotide polymorphisms (SNPs) with p‐values less than .05 from the LMM were selected to undergo the least absolute shrinkage and selector operator (Lasso) in the second stage (LMM‐Lasso); (iii) genes containing two or more rare SNPs were examined by performing the sequence kernel association test (gene‐based SKAT). A total of 1,225 cattle were genotyped with an Illumina BovineHD BeadChip containing 770,000 SNPs. After the quality‐control procedures, 1,217 individuals with 608,696 common SNPs and 105,787 rare SNPs (with 0.001 < minor allele frequency [MAF] <0.05) remained in the sample for analysis. A traditional LMM successfully mapped three genes associated with bone weight, while LMM‐Lasso identified nine genes, which included all genes found by traditional LMM. Only a single gene, EPHB3, surpassed the significance threshold after Bonferroni correction in gene‐based SKAT. In conclusion, based on functional annotation and results from previous endeavours, we believe that LCORL, RIMS2, LAP3, PRKAR2B, CHSY1, MAP2K6 and EPHB3 are candidate genes for bone weight. In general, such a comprehensive strategy for GWAS may be useful for researchers seeking to probe the full genetic architecture underlying economic traits in livestock.