灰黑拟牛肝菌的化学成分

从担子菌灰黑拟牛肝菌（Boletopsis grisea)新鲜子实体的乙醇提取物中首次分离得到10个化合物,包括8个酚性成分,1个含硫成分和1个脑苷脂,它们的结构经各种波谱数据分别鉴定为3－（4－乙酰氧基苯）－1,2,4,7,8－五乙酰氧基二苯并呋喃（1）,3－（4－乙酰氧基苯）－1,2,4－三乙酰氧基－7,8－二羟基二苯并呋喃（2）,3－（4－羟基苯）－1,2－二乙酰氧基－4,7,8－三羟基二苯并呋喃（3）,2,3－二乙酰氧基－4′,4″,5,6－四羟基对联三苯（4）,对苯二酚（5）,对羟基苯甲酸（6）,茴香酸（7）,对羟基苯甲醛（8）,硫代乙酐（9）和1－O－吡喃葡萄糖基－（2S,3R,4E,8E,2′R）-2-N-(2′-羟基棕榈酰）－9－甲基－4,8－sphin-gadienine(10)。其中化合物1,2,3有报道对5－脂氧化酶具有选择性抑制活性。4,9,10均为首次从该属真菌中分离得到。     

江苏省稻瘟病菌有性态的研究*

用标准菌株对１９９７～１９９９年在江苏省吴江市,宜兴市、通州市、高邮市和赣榆县采集的３２５个猪瘟病菌单孢分离菌株的可育性和交配型进行了测定,结果表明江苏省稻瘟病菌菌株的育性较低,可交配率为２２．７７％,可育率仅为７．０８％。不同年份、不同地区采集的猪瘟病菌茵株的性亲和力和交配型有较大的差异,三年的交配率分别为２６．６１％、８．２６％和３３．６４％;温州地区和赣榆地区菌株的交配率相对较高,分别为２６．１５％和２５．４２％,宜兴地区菌株的交配率较低,只有１５．３８％。江苏省稻瘟病菌菌株的交配型在不同年份亦出现很大差别,１９９７年２９个可交配菌株中有２１个菌株表现为ＭＡＴ１－２ 交配型,而１９９９年３６个可交配茵株均为ＭＡＴ１－１交配型。用江苏省稻瘟病菌的可育菌株进行互交,２５个组合中只有６个组合能产生子囊壳和子囊,但均不产生子囊孢子,提示江苏省稻瘟病菌在田间产生健康有性后代的几率不大。对杂交后代的遗传学分析表明,菌株的交配型是受单基因控制的。     

云南稻瘟病菌系谱与致病型的关系

为探究稻瘟病菌无性世代DNA水平的变异,寻找云南稻瘟病菌谱系(genetic lineage,G)和致病型之间的对应关系,根据稻瘟病菌散布的重复序列Pot2(Pyricularia oryzac transposon),对云南水稻主产区稻瘟病菌菌株DNA进行了rep-PCR(repetitive polymerase chain reaction)扩增,获得rep-PCR指纹。聚类分析将134个稻瘟病菌代表菌株划分为G1～G8等8个谱系,揭示云南水稻主产区稻瘟病菌无性系丰富的遗传多样性。进一步接种分析了8个谱系的29个稻瘟病菌菌株对33个云南主产区水稻品种的亲和性,依其毒性谱,采用STATISTICAL5．0软件的UP-GMA程序进行聚类分析,将其划分为P1～P6等6个致病型群(pathotype group)。结果表明同一谱系的稻瘟病菌菌株多数对应2～3个致病型群,少数1个或4个致病型群;但G1～G8等8个谱系中的部分菌株都可对应致病型群P2。因此,云南水稻主产区稻瘟病菌谱系和致病型群之间属于复杂关系类型。此外,33个水稻品种中的合系16和京国92抗全部29个稻瘟病菌株,云粳20和合系30对全部供试菌株表现感病,这对云南水稻主产区品种布局提供了稻瘟病抗性方面的依据。因此,从育种应用和生产实际需要出发,水稻品种抗瘟谱测定仍然必要。     

转拟南芥AtNPR1基因增强水稻对水稻白叶枯病和稻瘟病的抗性

AtNPR1基因是拟南芥系统获得抗性的一个重要调节基因,在拟南芥中过量表达AtNPR1基因能使拟南芥对细菌和真菌的抗性同时增强.为了研究在水稻中过量表达AtNPR1基因对水稻抗病性的影响,将该基因转入到广西主栽籼稻恢复系品种桂99中.经PCR验证得到了79株转基因植株,DNA斑点杂交表明ATNPR1基因已经整合到桂99染色体DNA中.Northern杂交和RT-PCR分析表明,AtNPR1基因在桂99中已经表达;同时还检测了转基因植株对水稻白叶枯病和稻瘟病的抗性,结果表明转基因植株对该两种病害的抗性均显著增强.     

稻瘟病菌(Magnaporthe grisea)诱导的水稻早期反应基因ER1的5' 端cDNA片段克隆及序列分析

研究高等生物基因表达与调控的一个重要方面是分离基因的编码区及其上游的调控序列（ＤｅＶｅｅｒ等１９９７）,这需要获得一个基因的ｃＤＮＡ全长及从植物基因组获取全基因。在前文（周建明等１９９９）中曾经分离了稻瘟病菌侵染诱导的水稻早期反应基因ＥＲ１的ｃＤＮＡ片段,但是运用ｍＲＮＡ差异显示技术分离的ｃＤＮＡ片段往往只有近ｍＲＮＡ３’端的一部分,难以反映基因的结构及功能特点,因此,必须进一步分离其５’端的部分才有可能比较全面地了解此基因的特点。ＲＡＣＥ（ｒａｐｉｄａｍｐｌｉｆｉｃａｔｉｏｎｏｆｃＤＮＡｅｎ…     

稻瘟病菌单克隆抗体的研制及其对稻瘟病菌附着胞形成的影响

稻温病菌的分生孢子、芽管、附着胞的混合物作为抗原免疫BALB/c小鼠,取免疫小鼠的脾细胞与SP2/0骨髓瘤细胞在50%PEG下融合成杂交瘤细胞,用间接ELISA筛选阳性孔,获11株单克隆抗体。间接免疫荧光试验表明其中4株单克隆抗体2B4、4A1、1D1和2H4分别与孢子、芽管或附着胞有特异性结合;Western blotting分析发现2B4、4A1、1D1单克隆抗体分别与孢子、芽管表面的提取物有不同的结合带;此四株单克隆抗体均干扰稻温病菌附着胞形成,并抑制稻温病菌在叶表的致病性。     

水稻广谱抗稻瘟病基因研究进展

稻瘟病是水稻生产中的最严重病害之一,由于稻瘟菌小种的高度变异性,垂直抗性基因难以持续控制稻瘟病的危害,因此,克隆和利用广谱持久抗瘟基因被认为是解决稻瘟病问题最经济有效的策略。本文从广谱抗源的筛选与利用,广谱抗瘟基因的定位、克隆与应用等方面对水稻广谱抗稻瘟病基因研究取得的进展进行了概述,并介绍了广谱抗性分子机理的最新研究进展。基于国内外稻瘟病抗性基因研究的现状及趋势,以及我国丰富的抗瘟水稻种质资源,克隆越来越多的广谱抗瘟基因具有重要的理论与应用价值。     

稻瘟菌Ⅰ型烯醇化酶基因全长cDNA的电子克隆

利用电子克隆技术从稻瘟菌中克隆到一个新的Ⅰ型烯醇化酶全长cDNA,暂命为MgEno-1。MgEno-1全长1571核薯酸,其预测的ORF为1317核苷酸,共编码438个氨基酸。起始密码子ATG位于第53位,终止密码子TAA位于第1369位。序列分析表明该烯醇化酶与丝状真菌中已报道的其它烯醇化酶高度同源,且长度一致,这暗示烯醇化酶基因进化上高度保守,甚至有可能像18SrRNA一样可作为进化尺度。这将是第一个用电子克隆技术从稻瘟菌中克隆到的基因。     

Structural Contribution of the Carbohydrate Moiety to the Alkaline Hydrolysis of Aryl Glycosylamine Linkages

Differential scanning calorimetry (DSC) thermograms of soybean protein isolate developed two peaks corresponded to 11S and 7S globulin, the denaturation temperatures of which were 93.3 and 76.5°C, respectively, with 94% water. These peaks shifted to higher temperatures with lower water contents of the sample. At 47% water, there were two peaks, at 149 and 118.7°C, and at 11% water, there was one peak at 180°C. The DSC thermogram measured during cooling and reheating gave no peak. The soybean protein isolate was heated with 24.5% water at 100°C and then mixed with more water to the water contents of 94%. This sample gave two peaks at temperatures close to those of the original soybean protein, indicating that the soybean protein was not denatured at temperatures even above 100°C when the water content was low.     

Tagging genes for blast resistance in rice via linkage to RFLP markers

Summary Both Pi-2(t) and Pi-4(t) genes of rice confer complete resistance to the blast fungal pathogen Pyricularia oryzae Cav. As economically important plant genes, they have been recently characterized phenotypically, yet nothing is known about their classical linkage associations and gene products. We report here the isolation of DNA markers closely linked to these blast resistance genes in rice. The DNA markers were identified by testing 142 mapped rice genomic clones as hybridization probes against Southern blots, consisting of DNA from pairs of nearly isogenic lines (NILs) with or without the target genes. Chromosomal segments introgressed from donor genomes were distinguished by restriction fragment length polymorphisms (RFLPs) between the NILs. Linkage associations of the clones with Pi-2(t) and Pi4(t) were verified using F₃ segregating populations of known blast reaction. Cosegregation of the resistant genotype and donor-derived allele indicated the presence of linkage between the DNA marker and a blast resistance gene. RFLP analysis showed that Pi-2(t) is closely linked to a single-copy DNA clone RG64 on chromosome 6, with a distance of 2.8+1.4(SE) cMorgans. Another blast resistance gene, Pi-4(t), is 15.3+4.2(SE) cMorgans away from a DNA clone RG869 on chromosome 12. These chromosomal regions can now be examined with additional markers to define the precise locations of Pi-2(t) and Pi-4(t). Tightly linked DNA markers may facilitate early selection for blast resistance genes in breeding programs. These markers may also be useful to map new genes for resistance to blast isolates. They may ultimately lead to the cloning of those genes via chromosome walking. The gene tagging approach demonstrated in this paper may apply to other genes of interest for both monogenic and polygenic traits.