人参灰霉病拮抗细菌的筛选及鉴定

为获取对灰葡萄孢Botrytis cinerea Pers.ex Fr.防效优良的菌株,采用滤纸片法和牛津杯法从105株菌株中筛选出7株拮抗性良好的菌株,采用平板对峙法对抑菌效果较好的菌株SZ-35进行抑菌谱测定,采用盆栽法研究其对人参灰霉病的防效及在人参体内的定殖能力,并通过形态学、生理生化特征、16S rDNA及gyrB基因测序确立其分类地位。结果显示,菌株SZ-35对灰葡萄孢的抑制作用最强,抑菌率和抑菌带宽分别为86.53%和12.20 mm,且具有广谱抑菌能力;菌株SZ-35可有效定殖于人参体内,对人参灰霉病的防效达76.42%,显著高于70%代森锰锌可湿性粉剂;通过形态特征、生理生化特征观察,以及16S rDNA及gyrB同源性序列对比分析,鉴定菌株SZ-35为解淀粉芽胞杆菌Bacillus amyloliquefaciens(GenBank登录号为KC511113)。研究表明,解淀粉芽胞杆菌SZ-35对灰葡萄孢具有良好的抑菌能力,且在人参中的定殖能力较好。     

The family 10 of plant pathogenesis-related proteins: Their structure,regulation, and function in response to biotic and abiotic stresses

The aim of this review is to present the current state of our understanding on the structure, regulation, and function of plant pathogenesis-related protein family 10 (PR-10). This protein family consists of relatively diverse members subgrouped into classes that suggest different functions. It is believed that PR-10 proteins are involved in plant defense because their genes are usually induced upon the attack of various pathogens and by environmental stresses. However, updated evidence shows that PR-10 proteins display several additional functions, including a role in developmental processes and enzymatic activities in secondary metabolism. Because of the complexity of the PR-10 gene family and its potential multiple functions, it is important to summarize current knowledge as basis for a further dissection of the functions of PR-10 proteins and a better understanding of their structural adaptation. This paper provides the first review of existing knowledge of plant PR-10 proteins and examines their structural and functional adaptations.     

多抗霉素B在鲜人参中的储藏稳定性

建立了鲜人参样品中多抗霉素B的简易样品前处理程序和HPLC-MS/MS检测方法,对0～150 d低温储藏的鲜人参添加样品进行了分析,考察了多抗霉素B在鲜人参样品中的低温储藏稳定性。结果表明,所建立分析方法在0.01～2.0 mg/L范围内线性响应良好,0.2～5.0 mg/kg添加水平的平均回收率为78.0%～94.7%,定量检测限为0.275 mg/kg;鲜人参样品在-18℃和-20℃储藏条件下多抗霉素B的平均降解率均小于30%,说明多抗霉素B在鲜人参样品中至少可以稳定储藏150 d。该结果为多抗霉素B在人参上的残留登记试验提供了可靠的科学依据。     

Joint effects of biotic and abiotic stressors on winter wheat suppression of Bromus tectorum

In winter wheat systems in the Northern Great Plains of the United States, Bromus tectorum and wheat streak mosaic virus (WSMV) commonly co‐occur. While independent effects of these pests on wheat yields have been well documented, to our knowledge, no study has investigated whether WSMV modifies interactions between wheat and B. tectorum. Furthermore, the impact that environmental stressors such as nutrient availability have on these interactions has not been addressed. We conducted a randomised split‐plot field study over 2 years to investigate the effects of WSMV and nitrate (N) availability on winter wheat suppression of Bromus tectorum. The study included four N treatments (10–19, 20–31, 31–84, and 85–207 kg ha^?1) and two WSMV treatments (mechanically inoculated or control). Increasing soil N increased the susceptibility of wheat to WSMV infection. In 2009, wheat in the lowest and highest N levels had 24% and 65% of plants infected respectively. However, regression analysis indicated that interactive effects of wheat competition, N and WSMV did not play a consistent role in B. tectorum growth. Specifically, the effect of both wheat density and distance from row on B. tectorum biomass remained constant across inoculation treatments, suggesting that wheat inoculated with WSMV suppressed B. tectorum as effectively as healthy wheat. Furthermore, wheat had a greater impact on B. tectorum growth in higher N environments, even though incidence of WSMV infection in wheat was highest. Overall, our results suggest that WSMV infection may not change the ability of wheat to suppress B. tectorum.     

植物内生蜡样芽孢杆菌M22 Mn-SOD基因的克隆及在大肠杆菌中表达

 通过PCR和反向PCR,从蜡样芽孢杆菌M22中扩增到2条长度为1 322 bp和1 395 bp的基因片段(GenBank登录号为AY540749和AY468485),分别含657 bp和627 bp的开放阅读框,各自编码218个和208个氨基酸残基的功能蛋白。2个蛋白氨基酸序列同源性为46%,均不含信号肽。与其它锰超氧化物歧化酶序列同源性高,保守氨基酸残基类型及位置与其它Mn-SOD相同,可确定2个基因均为蜡样芽孢杆菌Mn-SOD基因。分别将2个基因的开放阅读框插入载体pET-22b (+)构建表达质粒pET-sodA,转化大肠杆菌BL21(DE3),IPTG诱导蛋白表达。SDS-PAGE显示融合蛋白相对分子质量分别为28 kD和27 kD。转入pET-sodA的SOD缺陷型大肠杆菌QC779转化子恢复在10μmol/L paraquat的LB平板上生长的能力。活性电泳显示,M22的Mn-SOD在QC779中成功表达。     

Molecular cloning of two chitinase genes from Serratia marcescens and their expression in Pseudomonas species

Two chitinase encoding EcoRI fragments from the enteric soil bacterium Serratia marcescens were cloned. From a genomic library of 5686 transductants, 21 expressed chitinase activity as indicated by clearing of a chitin-containing medium. The chitinase encoding clones could be divided into two groups. Four had an 18kb EcoRI fragment and 17 had a 9·4 kb EcoRI fragment. In Southern hybridization experiments the 18kb fragment showed no homology to the 9·4 kb fragment and restriction enzyme maps indicated no similarity. Triparental mating with fluorescent Pseudomonas spp. yielded transconjugants that expressed chitinase activity, inhibited growth of Fusarium oxysporum f. sp. redolens germ tubes and reduced disease of radish caused by the same fungus.     

玉米SPXs家族基因的鉴定与表达规律分析

SPXs(SPX-domain-containing proteins)家族基因在真核生物无机磷酸盐(Pi)的传感、信号转导和转运中发挥着重要作用,但玉米SPXs家族基因的相关研究未见报道.本研究利用生物信息学手段鉴定了15个玉米SPXs家族基因,通过系统进化和保守结构域分析将其分为SPX-EXS、SPX、SPX-Zi...     

广聚萤叶甲Vg基因的鉴定及表达分析

卵黄原蛋白(vitellogenin, Vg)作为雌性多功能生殖蛋白, 为卵黄发生提供所需的储备能源。为明确Vg基因在广聚萤叶甲Ophraella communa生殖过程中的潜在作用, 本研究通过RT-PCR技术克隆得到广聚萤叶甲的3个Vg基因, 其OcVg1, OcVg2和OcVg3开放阅读框(ORF)分别为5 310、5 322 bp和5 298 bp, 对应编码1 768、1 772和1 764个氨基酸。其OcVgs蛋白具有LLTP超家族的保守结构域:LPD_N、DUF1943和VWD结构域; 多位于N-端的多聚丝氨酸区(polyserine domains), 保守的GL/ICG、R/KXXR/K、DGXR基序和C-端半胱氨酸残基等。构建系统进化树发现, OcVgs与鞘翅目昆虫聚为一支。时空表达分析发现, OcVgs基因在不同组织及发育阶段的表达动态相似, 在脂肪体中特异性高表达(P<0.05); 在成虫羽化后的性成熟阶段的表达量最高, 幼虫期的表达水平可以忽略不计(P<0.05)。研究结果为深入理解广聚萤叶甲生殖作用的分子机制奠定基础。     

中国不同地区草地贪夜蛾种群生物型分子特征分析

原产于美洲的草地贪夜蛾已入侵我国,对我国粮食生产安全构成重大威胁。在美洲,该虫的寄主类型、迁飞行为以及抗药性等方面因群体分化而存在较大差异。本研究利用2个分子标记对中国13省(市、自治区)131个县市的318份样品进行群体遗传特征比较,基于线粒体COⅠ基因分析结果显示96%以上为水稻型,玉米型比例不到4%,且中国样品COⅠ序列特征与美国佛罗里达州种群有很高的一致性,而基于核基因组Tpi基因分析结果表明所有样品单倍型特点均表现为玉米型。分析认为,入侵我国的草地贪夜蛾群体很可能来自一个水稻型母本和玉米型父本杂交群体的后代,在长期的演化扩散过程中,玉米型的核基因组占据了主导地位,从而成为一种特殊的玉米型。厘清入侵中国的草地贪夜蛾具体的遗传特征属性,对于风险评估、精准监测和科学防控具有重要指导意义。     

油菜素内酯调控植物响应非生物逆境胁迫的生理机制

油菜素内酯属于甾体类激素中的油菜素甾醇类物质,是其生物合成中产生的活性副产物,对植物生长发育具有重要的调节作用。在非生物胁迫条件下,外源施用油菜素内酯可以增强植物的抗氧化系统,增加渗透物质水平,维持内源激素平衡,稳定离子和水分平衡,改善气体交换属性和光合作用,最终减轻逆境危害并促进植物生长。该文综述油菜素内酯对非生物胁迫下植物生长、生理调节的影响及调控途径,对油菜素内酯提高植物抗逆境能力的未来研究方向进行展望。     

稻瘟菌Rho族蛋白及其编码基因表达特点

 Rho族蛋白是Ras超家族小G蛋白最主要成员,在真核生物中极为保守,包括Rho、Rac、Cdc42等,作为分子开关,参与细胞极性、细胞运动、细胞形状、细胞间及细胞与其基质互作等多个信号转导途径。基因组数据库分析显示,稻瘟菌中含有30余个小G蛋白,其中7个可能是Rho族蛋白,包括Cdc42、Rac1及5个Rho亚家族蛋白。结构分析表明,7个推导的Rho族蛋白均具有典型结构域。进一步以半定量RT-PCR分析了稻瘟菌7个Rho族蛋白编码基因在菌丝、分生孢子、芽管以及附着胞等不同生长发育阶段的表达情况。结果表明,Rho族蛋白编码基因具有不同的表达模式。通过BLASTP搜索GenBank等数据库,获得迄今已公布的真菌Rho1、Cdc42和Rac1蛋白序列,建立了系统发育树,一定程度地反映了真菌进化关系,说明在真菌进化中Rho族蛋白的结构与功能也经历了共同演化的过程。     

Molecular characterization and phylogenetic analysis of Citrus viroid I-LSS variants from citrus in Pakistan and China reveals their possible geographic origin

CVd-I-LSS (low sequence similarity), a variant of Citrus bent leaf viroid (CBLVd), was first discovered in Japan, and its distribution is currently limited to Japan and Iran. In the present study, seven CVd-I-LSS isolates were detected from different citrus hosts (Citrus sinensis, C. reticulata and C. limettioides) in Pakistan and China. Genetic diversity analysis of 49 cDNAs of CVd-I-LSS isolates showed that the Pakistan population was more diverse than that tested from Japan or China. Phylogenetic analysis clustered the predominant sequences examined into three main clades. Only sequences from the Pakistan isolates were found in all three clades, suggesting Pakistan may be the original source of CVd-I-LSS. Cultivar import records and the close phylogenetic relationship found between CVd-I-LSS from China and Japan suggested that the viroid isolated from China might have originated from Japan.