利用2个F_2群体整合中国豌豆高密度SSR遗传连锁图谱

豌豆(Pisum sativum L.)是一种重要的食用豆类作物,在全世界范围内广泛种植,既可作为人类食物,也可作为牲畜饲料。用SSR标记构建的遗传连锁图谱在豌豆和其他作物的标记辅助育种中发挥着重要的作用。尽管对豌豆遗传连锁作图的研究已有悠久历史,但公众可获得且可转移的SSR标记以及基于遗传独特的中国豌豆种质的高密度遗传连锁图谱仍然有限。为了获得更多可转移的SSR标记和中国豌豆的高密度遗传连锁图谱,本研究首先从自主开发和文献获取的12,491个全基因组SSR标记中筛选了617个多态性SSR标记,并用于G0003973×G0005527 F_2群体遗传连锁图谱的加密。加密后的图谱全长扩展到5330.6 cM,包含603个SSR标记,标记平均间距离8.8 cM,相比之前的图谱有明显改善。基于上述结果,我们又筛选了119个具有多态性的SSR标记,用于构建大样本W6-22600×W6-15174 F_2群体的遗传连锁图谱,新图谱累积长度为1127.1 cM,包含118个SSR标记,装配在7条连锁群上。最后,将来自以上2个遗传图谱的数据进行整合,得到了一张覆盖范围6592.6 cM的整合图谱,包含668个SSR标记,由509个基因组SSR、134个EST-SSR和25个锚定标记组成,分布在7条连锁群上。这些SSR标记和遗传连锁图谱将为豌豆的遗传研究和标记辅助育种提供有力工具。     

韭菜全长转录组SSR信息分析及分子标记开发

利用MISA软件筛选韭菜（Allium tuberosum）全长转录组测序获得的49 876条（大于500 bp）转录本序列（89.44 Mb），共检测出13 111个SSR位点，分布在10 332条转录本中，SSR出现频率为26.29%，平均分布距离为6.82 kb。在搜索的6种SSR位点类型中，1 ~ 3个核苷酸重复类型占主要地位，占总SSR位点数的98.74%，其中单核苷酸、二核苷酸和三核苷酸重复类型分别为66.55%、12.52%、19.67%。发现重复序列的基序有103个，其中二核苷酸和三核苷酸重复类型中出现频率高的基序有AC/GT（2.54%）、CA/TG（2.29%）、GAA/TTC（1.85%）和AAG/CTT（1.60%）。重复序列的长度在10 ~ 289 bp之间，其中小于20 bp的有11 128个（84.88%），大于20 bp的有1 983个（15.12%）。根据这些SSR位点，共设计出3 311对SSR引物，在随机选取的208对引物中有164对（78.85%）能进行有效扩增，其中39对引物在24份韭菜种质资源中表现出多态性。利用多态性引物SSR41，鉴定出‘马蔺韭’ב791’后代中的6株有性生殖后代。以上结果表明，基于韭菜全长转录组测序开发的SSR标记可以为韭菜的遗传多样性分析、种质资源鉴定和有性生殖后代筛选提供充足可靠的标记来源。     

Distribution and genetic diversity of Dothistroma septosporum in Pinus brutia forests of south-western Turkey

Dothistroma needle blight (DNB) is a serious disease of the Pinaceae, mainly Pinus species, caused by the fungi Dothistroma septosporum and D. pini. Both species are regarded as invasive forest pathogens worldwide, with rising incidence in central and northern Europe over the last three decades. In this work, 29 sites were investigated between 2013 and 2015 in south-western Turkey. Morphological examination of needles confirmed DNB infection (i.e., Dothistroma conidiospores observed) at 18 sites, and a total of 108 Dothistroma sp. isolates were obtained from 11 of the sites. Host age seemed to be an important factor in both occurrence and severity of DNB in Pinus brutia forests. Continuous rainy days, especially in December, may increase severity of disease; however, extreme rain events may reduce available conidiospores on plant tissues or in the air. Species-specific mating type primers showed that all isolates were D. septosporum; D. pini was not detected. The mating type ratio was close to 1:1, indicating sexual recombination was occurring. Eleven microsatellite markers revealed 59 unique multilocus haplotypes (MLHs) among the 73 isolates originating from different conidiomata. The majority of MLHs were represented by a single isolate (n = 52) and only one MLH was shared between two localities. Analyses showed high genetic diversity, isolation-by-distance, and clear population clusters. These findings suggest that D. septosporum is well established in south-western Turkey and is probably not a recent introduction.     

陆地棉种质资源抗旱性状的关联分析

干旱是导致全世界棉花严重减产、纤维品质下降的重要因素,因此获得高产、优质、耐旱的棉花新品种一直是棉花的育种目标。本研究选取217份陆地棉栽培种组成的自然群体为研究对象,采用全生育期处理组灌水量为对照组50%的干旱胁迫处理,并在处理后期对217份材料的株高、衣分、单铃重等18个性状进行2年2点的表型鉴定,干旱胁迫后,群体间响应差异明显,多个表型性状在对照和处理间表现显著差异。通过BLUP分析表型数据并计算各性状的抗旱系数;全基因组范围选取的214对多态性SSR分子标记扫描群体,共检测到393个多态性位点,基因多样性系数平均值为0.402,范围为0.072~0.631,PIC值平均为0.329,范围为0.070~0.560;群体结构分析表明,该群体可分为2个亚群。用上述SSR标记分别对18个性状的抗旱系数进行关联分析,共关联到76个极显著位点(P<0.01),表型变异解释率为2.930%~7.218%,其中共有14个标记位点能同时被2种或以上性状检测到。研究结果可为后期棉花杂交育种亲本选择及抗旱分子标记辅助育种提供理论基础及参考依据。     

矮化型湖北海棠种质资源评价与鉴定

在前人研究基础上对初选出的4个矮化型湖北海棠种质资源，以M系砧木(矮化或半矮化)和普通湖北海棠（乔化）为对照，从无融合生殖特性、矮化相关指标以及作为苹果砧木矮化性比较试验等方面进行检测、分析，并结合SSR分子标记鉴定，发掘出具有无融合生殖特性的湖北海棠半矮化品系‘龙王1号’、‘龙王2号’、‘兴山16号’和矮化品系‘兴山24号’，为苹果矮化栽培提供优良矮化砧木。     

Identification of a novel recessive gene for resistance to powdery mildew (Blumeria graminis f. sp. hordei) in barley (Hordeum vulgare)

One of the most important diseases of barley (Hordeum vulgare) is powdery mildew, caused by Blumeria graminis f. sp. hordei. Spring barley line 173-1-2 was selected from a Moroccan landrace and revealed broad-spectrum resistance to powdery mildew. The objective of this study was to map and characterize the gene for seedling powdery mildew resistance in this line. After crossing with the susceptible cultivar ‘Manchuria’, genetic analysis of F₂ and F₃ families at the seedling stage revealed powdery mildew resistance in line 173-1-2 conditioned by a single recessive gene. Molecular analysis of non-segregating homozygous resistant and homozygous susceptible F₂ plants conducted on the DArTseq platform (Diversity Arrays Technology Pty Ltd) identified significant markers which were converted to allele-specific PCR markers and tested among 94 F₂ individuals. The new resistance gene was mapped on the long arm of chromosome 6H. No other powdery mildew recessive resistance gene has been located on 6H so far. Therefore, we concluded that the 173-1-2 barley line carries a novel recessive resistance gene designated as mlmr.     

GASTRIC EMPTYING OF SOLID RADIOPAQUE MARKERS IN HEALTHY DOGS

The gastric emptying of 1.5 mm diameter (small) and 5.0 mm diameter (large) radiopaque markers (BIPS) was assessed in 20 dogs. The markers were fed to the dogs in a test meal and abdominal radiographs were made hourly thereafter. Studies were repeated three times in each dog. The variation between two veterinarians interpreting the radiographs was low. The sex, age and day of the study did not have a significant effect on the lag phase or the time taken to empty 25%, 50% and 75% of the markers (T₂₅, T₅₀ and T₇₅ respectively). There was a weak but significant positive correlation between the body weight and T₅₀. There was no significant difference in gastric emptying parameters between the large and small markers.
The mean gastric emptying versus time curve of the small markers on day one was chosen to represent the reference curve for healthy dogs. The lag phase of the small markers on day one was 2.45 ± 2.04 hours, the T₂₅ was 4.85 ± 2.15 hours, the T₅₀ was 6.05 ± 2.99 hours and the T₇₅ was 8.32 ± 2.72 hours (mean ± SD).     

牛羊多胎性状的分子遗传基础研究

本研究采用了RAPD、PCR RFLP、微卫星、PCR SSCP、序列分析等方法对2个牛品种(秦川牛和荷斯坦奶牛共60头)、6个中国固有绵羊品种(多胎品种小尾寒羊,双胎品种大尾寒羊,单胎品种兰州大尾羊、蒙古羊、同羊和哈萨克羊共197余只`进行了分子遗传基础研究,旨在寻找牛羊多胎性状合适的分子标记,为进一步对牛双胎基因、绵羊多胎基因的探索和高繁殖率牛羊的选育提供科学依据.     

DNA polymorphism in the chicken growth hormone gene: Association with egg production

Restriction fragment length polymorphic markers in the chicken growth hormone (GH) gene were tested for their association with egg production traits. Alleles of GH were determined in 3 non‐inbred strains from different genetic bases. The frequency of PS1 (+) allele in the three strains was very low in contrast to the layer strain previously reported. Results of the present study indicate that the frequency of PS (+) is related to egg production and that the PS1 (+) allele may be used as a genetic marker for selection in egg production.     

Applications of terpene analysis in forest genetics

Terpenoid substances in forest trees are versatile biochemical systems for use as genetic markers and for studying genetic regulation at the biochemical level. Univariate, multivariate and correlative data analyses from numerous studies on different coniferous species are presented. These data indicate that fitness values for most terpenes examined are probably so low as to be unmeasurable except in long evolutionary time spans. Variation patterns for monoterpenes often closely parallel racial differentiation for morphological traits and reflect the migratory history of species and species-complexes. Random drift and gene flow are likely the major influences on genetic organization of terpene variability. Mutation in regulatory genes may be responsible for quantitative variation within major gene systems for terpenes. The mono-, sesqui- and diterpene systems in conifers offer good opportunities for research on the nature of gene regulation in plants and its evolutionary significance.