Identification of genes expressed by Phakopsora pachyrhizi,the pathogen causing soybean rust,at a late stage of infection of susceptible soybean leaves

Soybean is one of the top five agricultural products in the United States and is highly susceptible to Phakopsora pachyrhizi, an exotic obligate biotrophic fungus. The little amount of genomic information about P. pachyrhizi limits understanding of the soybean–soybean rust pathogen interaction and the possibility of engineering resistance to this pathogen in soybean. Illumina mRNA‐Seq analysis revealed P. pachyrhizi genes expressed during a biotrophic interaction between P. pachyrhizi and soybean during fungal sporulation 10 days after inoculation. Approximately 2·4 million DNA sequences representing portions of potential P. pachyrhizi genes were assembled into 32 940 contigs that were used to search against expressed sequence tag (EST), protein and conserved domain databases. About 7500 contigs represent newly discovered P. pachyrhizi sequences. Of these, 527 shared similarity to genes encoding fungal proteins involved in different metabolic pathways such as galactose and glycogen metabolism, glycolysis, the citrate cycle, fatty acid metabolism, amino acid metabolism, proteolysis, protein synthesis, cell cycle division and mitosis, and cell wall biogenesis. Almost 7000 potential P. pachyrhizi genes are still of unknown function. Such information may be useful in the development of new methods of broadening resistance of soybean to P. pachyrhizi, including the silencing of important P. pachyrhizi genes, and also to understand the molecular basis of soybean–P. pachyrhizi interactions.     

Low diversity and fast evolution in the population of Puccinia triticina causing durum wheat leaf rust in France from 1999 to 2009, as revealed by an adapted differential set

No internationally agreed differential set is available for characterization of virulences in populations of Puccinia triticina causing wheat leaf rust on durum wheat. In a first step, 73 potentially differential host genotypes were tested with 96 durum leaf rust isolates collected in France. A differential set, adapted to the local epidemiological context and useful for comparison with international studies was selected, including French commercial cultivars, Thatcher lines with Lr genes, and international cultivars. In the second step, a sample of 310 isolates collected in France from 1999 to 2009 was characterized on this set. Diversity was very low, as only five pathotypes were distinguished. Genotyping of a subset of 76 isolates according to 20 SSR markers confirmed this low diversity, with 73 isolates belonging to a single dominant genotype. Population was strongly shaped by cultivars, and the findings explain the successive breakdown of resistance sources deployed in French durum wheat cultivars. The gene Lr14a, suggested to be an efficient source of resistance in several European and American countries, was overcome by pathotypes frequent in France since 2000. Postulation of resistance genes in the commercial cultivars led to a proposed simplified version of the differential set. This study, providing new information about leaf rust resistance genes present in the French durum wheat germplasm, highlights the need to diversify sources of resistance to P. triticina in this germplasm. The results are also discussed in terms of relatedness and intercontinental migration of P. triticina on durum wheat.     

黄河下游灌区可持续发展的对策研究

分析了影响黄河下游灌区可持续发展的技术因素、非技术因素,从技术措施和管理措施两方面探讨引黄灌区可持续发展思路,提出实现引黄灌区灌溉可持续发展的对策:一要坚定可持续发展信念;二要建立高效有序的水资源管理模式;三要建立用水民主管理机制。     

黄河低洼盐碱地生态渔业的调查与思考

在对中宁县黄河低洼盐碱地改良发展生态渔业简要介绍的基础上,分析了存在的问题并提出了相应的对策。     

黄河首曲湿地不同生境对鸟类群落结构的影响

于2011年夏季对黄河首曲湿地中河曲马场、阿万仓、曼日玛3种典型生境下的夏季鸟类种类和数量进行了详细调查,同时以样方法调查其植被数量及种类,以分析其植物群落结构特征及环境因素对鸟类群落结构的影响。研究发现,鸟类群落结构受其生境影响显著。     

小麦转录因子基因TabZIP20的克隆及其在小麦-条锈菌互作中的表达

bZIP转录因子已经在多种植物中被报道广泛参与抗病,但是对于bZIP转录因子在小麦与条锈菌互作过程中的抗病机制的研究很少。因此,通过电子克隆及RT PCR方法从条锈诱导的小麦水源11中克隆得到一个具有1 005 bp完整ORF,编码334个氨基酸,且具有bZIP保守结构域的小麦TabZIP转录因子基因。将该基因和拟南芥的基因组比对发现其和 AtbZIP20相似度最高,故命名该基因为TabZIP20。通过转化洋葱表皮细胞发现该基因编码的蛋白定位于细胞核;利用实时定量PCR分析了该基因在小麦与条锈菌亲和与非亲和组合中的表达情况,结果表明该基因在小麦对条锈菌的抗病反应中受条锈菌诱导表达。可见,TabZIP20参与小麦对条锈病的抗病反应,但具体作用机制仍待研究。     

小偃6号高温抗条锈病的表达规律

植物的高温抗病性是由较高环境温度所诱导的一种低反应型抗病性,由主效基因控制,易于鉴选和利用,有很高的应用价值.小偃6号是一个具有全生育期高温抗病性的品种,不同生育阶段之间高温抗病性强度没有差异,花斑期更有利于高温抗病性的表达,最低诱导温度为18～21℃,最短诱导时间为6～12 h;在高温抗病性表达时条锈菌的产孢量下降,产孢期缩短.     

东黄海鲐鱼渔业资源租金初探

资源租金是自然资源价值的表现形式,合理收取资源租金既可促进渔业资源的可持续利用,同时也为渔业资源再生产提供必要的资本。以生物经济模型为基础,以最大可持续产量（maximum sustainable yield,MSY）处所获得的资源租金作为参考,估算2008年东黄海鲐鱼渔业资源租金状况。研究认为,2008年东黄海鲐鱼资源的全部价值为373.03百万元,其所捕捞的渔获价值为179.70百万元, MSY时的资源价值为157.89百万元。同时,随着鲐鱼的繁殖生长,平均每年渔获可增加的经济价值为13.81百万元,渔业净利润为9.81百万元。以2008年中日韩3国近海鲐鱼的生产数据和经济数据为基准,累计5年的产量和利润分别为144.63万吨和4.04亿元,累计10年的产量和利润分别为309.5万吨和12.67亿元,累计20年的利润636.87万吨和30.44亿元。针对上述情况,建议对我国近海渔业资源管理实行改革,通过收取资源租金的形式来降低捕捞强度,这不仅可以确保近海渔业资源的可持续利用,同时也体现了资源所有者的权益,研究结果对促进我国近海渔业可持续发展具有重要的借鉴意义。     

奶牛胚胎远距离运输移植黄牛技术研究

超数排卵处理黑白花奶牛１１头，有效８头，超排有效率７２．７％，获总卵数４０枚，头均获卵５枚（４／８），可用胚２６枚，头均可用胚３．３枚（２６／８），胚胎可用率６５％。移植受体牛２３头，妊娠１０头，移植成功率４３．５％（２３／１０）。     

黄河源区沼泽湿地退化过程中植物群落特征的变化

利用空间序列代替时间序列的方法,研究了黄河源区沼泽湿地退化过程中植物群落空间分布特征的变化。结果显示:在湿地退化过程中,经沼泽化草甸、高寒草甸到退化草地,1)群落内物种发生更替,优势种藏嵩草(Kobresia tibetica)逐渐退出群落,多年生杂类草则逐渐增多并演变成优势种;2)物种丰富度、均匀度和多样性指数先升后降,优势度指数先降后升,峰值均出现在高寒草甸阶段;3)群落生产力呈现下降态势,多年生杂类草所占比例随演替年限的增大而急剧增加;4)物种-多度格局由生物统计型的对数正态分布逐渐转变为生态位型的ZipfMandelbrot分布。