Preliminary Studies on CPG/Hinf Ⅰ RFLP Groups of Citrus tristeza virus Infected Sweet Oranges in China

Citrus tristeza virus (CTV) causes economically important losses to the citrus industry worldwide. Mild strain cross protection (MSCP) against tristeza has hardly been practised due to mixed infection of different CTV-strains and little background of its molecular biology in China. For better cognition on CTV, 192 sweet orange samples collected from eight provinces (Chongqing, Sichuan, Fujian, Hunan, Guangxi, Yunnan, Guangdong and Jiangxi) were tested by direct tissue blot immuno-assay (DTBIA), and 158 of them were tested positively, which therefore were subjected to coat protein gene (CPG)/Hinf Ⅰ restriction fragment length polymorphism (RFLP) analysis. Sample bulks were compared between Chongqing and Fujian by some statistical data, including ratios of single infection and mixed infection to local samples, proportions of CTV isolates with single RFLP groups, and rates of each RFLP group. The simplified analysis of samples from the other six provinces were then conducted. This study suggests that CTV isolates with CPG/Hinf Ⅰ RFLP groups Ⅲ and Ⅰ are the main epidemic ones in China, and mixed infection of CTV in fields are popular. Based on observation of severity of stem-pitting symptom in field trees, CTV isolates with CPG/Hinf Ⅰ RFLP groups Ⅲ and Ⅰ caused severe stem-pittings in sweet oranges in China.     

中国野生柑橘上衰退病毒分离株分子特征分析

 【目的】了解中国野生柑橘上携带柑橘衰退病毒（CTV）分离株的CP/HinfⅠRFLP组群构成和分子特征。【方法】运用RT-PCR对采自中国云南、广西、四川、湖南、江西等省11个野生柑橘上CTV分离株的病毒衣壳蛋白基因(CPG)进行扩增，利用RFLP和SSCP对CPG进行分析，并将测定的CPG序列进行同源性比较和聚类分析。【结果】发现野生柑橘上11个CTV分离株以单一组群感染为主；这些CTV分离株CPG的核苷酸序列和相应的氨基酸序列同源性分别为92.5％～99.5％和95.0％～100％；与GenBank收录的9个全基因组CTV分离株的相应基因序列进行聚类分析，其核苷酸序列和氨基酸序列同源性分别为92.1％～98.8％和94.6％～100％。【结论】序列同源性比较说明CTV CPG具有高度保守性，同时系统进化分析表明收集到的野生CTV分离株与国外分离株分属5大类群，具有较复杂的亲缘关系。     

Preliminary Studies on CPG/Hinf Ⅰ RFLP Groups of Citrus tristeza virus Infected Sweet Oranges in China

Citrus tristeza virus （CTV） causes economically important losses to the citrus industry worldwide. Mild strain cross protection （MSCP） against tristeza has hardly been practised due to mixed infection of different CTV-strains and little background of its molecular biology in China. For better cognition on CTV, 192 sweet orange samples collected from eight provinces （Chongqing, Sichuan, Fujian, Hunan, Guangxi, Yunnan, Guangdong and Jiangxi） were tested by direct tissue blot immuno-assay （DTBIA）, and 158 of them were tested positively, which therefore were subjected to coat protein gene （CPG）/Hinf Ⅰ restriction fragment length polymorphism （RFLP） analysis. Sample bulks were compared between Chongqing and Fujian by some statistical data, including ratios of single infection and mixed infection to local samples, proportions of CTV isolates with single RFLP groups, and rates of each RFLP group. The simplified analysis of samples from the other six provinces were then conducted. This study suggests that CTV isolates with CPG/Hinf Ⅰ RFLP groups Ⅲ and Ⅰ are the main epidemic ones in China, and mixed infection of CTV in fields are popular. Based on observation of severity of stem-pitting symptom in field trees, CTV isolates with CPG/Hinf Ⅰ RFLP groups Ⅲ and Ⅰ caused severe stem-pittings in sweet oranges in China.     

6S rDNA-RFLP法快速鉴定蒙古国传统乳制品中的乳酸菌

以17株标准菌株为参照,采用限制性片段长度多态性（RFLP）分析和16S rDNA序列分析相结合的技术,对分离自蒙古国5个地区传统乳制品中的55株乳酸菌进行了快速鉴定。结果表明,通过限制性内切酶AluⅠ、HaeⅢ、BsmaⅠ、TspRⅠ和HinfⅠ的指纹图谱分析,将49株乳杆菌和2株片球菌准确鉴定到种,其他4株肠球菌鉴定到属。采用16S rDNA-RFLP方法鉴定乳酸菌具有准确性,可靠性和高效性。     

浙江地区不同寄主来源的炭疽菌ITS序列PCR-RFLP多态性分析

应用核糖体DNA (ribo-somal DNA,rDNA)的ITS( internal transcribed spacer,ITS)区的RFLP序列的多态性,分析32个不同寄主来源的炭疽菌株的遗传多样性.利用ITS1及ITS4通用引物对扩增各菌株的rDNA的内转录间隔区(ITS1-5.8S-ITS2)获得长约600 bp片段.ITS-RFLP共迁带UPGMA聚类分析的结果表明所有来自不同寄主的炭疽菌菌株(含福建及云南菌株)都以较高的相似系数(＞0.60)聚为一类,具有较近的 亲缘关系;同时试验中所有酶切位点的综合Gst系数达到0.82,说明不同菌株间的ITS具有丰富的多态性.     

皖南黑猪H-FABP基因5'-上游区和第二内含子的多态性分析及克隆测序

对皖南黑猪心脏脂肪酸结合蛋白(H-FABP)基因5’-上游区和第二内含子的多态性进行分析及克隆测序,为开展皖南黑猪肉质性状分子育种奠定理论基础。采用PCR-RFLP(HinfⅠ、HaeⅢ、MspⅠ3种限制性内切酶)分子标记技术,分析了184头皖南黑猪H-FABP基因5’-上游区和第二内含子区的遗传变异情况,并对该基因的多态片段进行克隆和测序分析。结果显示:(1)在5’-上游区,HinfⅠ位点上存在多态性,等位基因H的基因频率为0.62,表现为中度多态(PIC=0.359 6);在第二内含子区,HaeⅢ位点上存在多态性,等位基因D的基因频率为0.92,表现为低度多态(PIC=0.130 7);而MspⅠ位点上尚未检测到多态,基因型均为AA型;HinfⅠ*位点上也存在多态性,等位基因B的基因频率为0.78,表现为中度多态(PIC=0.282 4);(2)χ2检验表明,除5’-上游区HinfⅠ多态位点外,其他3个位点均达到Hardy-Weinberg平衡状态(P0.05);(3)对H-FABP基因3个多态片段进行克隆测序分析发现,HinfⅠ-RFLP是由于1 324 bp处存在T→C的突变引起,HaeⅢ-RFLP是由于1811bp处存在C→G的突变引起,HinfⅠ*-RFLP是由于1 970 bp处存在C→T的突变引起。本试验确证了皖南黑猪H-FABP基因5’-上游区的多态位点并在第二内含子区检测到了HaeⅢ和Hinf*Ⅰ多态位点,这可为进一步分析H-FABP基因不同基因型与IMF含量的关系,以及确定影响IMF沉积的主效基因提供一定的数据基础。     

橘蚜传播柑橘衰退病毒的研究进展

就橘蚜传播柑橘衰退病毒 (CTV)的传毒特性、传毒率、影响传毒率因素、与柑橘衰退病流行的关系、对混合株系的虫传分离作用以及带毒橘蚜的分子生物学检测等研究进展作一综述 .橘蚜传播 CTV的方式为非循回型半持久式 ,其从甜橙和墨西哥莱檬植株上传播 CTV的效率高于棉蚜、橘二叉蚜和绣线菊蚜等蚜虫 .橘蚜对 CTV不同株系的传毒率有所差异 ,对重型株系的传毒率较轻型株系高 .影响传毒率的因素有蚜虫发育虫态、毒源植物、接毒植物和环境条件等 .橘蚜与酸橙砧甜橙衰退病的发生与流行 ,特别是衰退型强株系衰退病的发生与流行有密切相关性 ,它是甜橙衰退病发生与流行的最主要传播介体 .橘蚜对 CTV具有分离株系的作用 ,通过单虫传播 ,可以将混合感染状态的 CTV不同株系分离而获得纯化株系 .检测橘蚜携带 CTV的分子生物学反转录 -聚合酶链式反应技术已建立 ,并已应用于检测橘蚜等蚜虫的单虫带毒情况 .讨论认为 ,不同发育虫态、毒源植物、接毒植物和环境条件等因素对橘蚜传播 CTV的影响 ,特别是毒源植物和温度条件对橘蚜传毒率的影响 ,及利用橘蚜单虫传播分离 CTV株系等方面的研究有待进一步加强     

乌克兰鳞鲤同工酶及mtDNA D-loop区段的RFLP分析

[目的]分析乌克兰鳞鲤的遗传结构,以期为乌克兰鳞鲤的遗传育种研究提供依据。[方法]利用水平式淀粉凝胶电泳法对乌克兰鳞鲤（46尾）进行了AAT、α-GPD、GPI、IDH、MDH和PGM共6种同工酶以及肌浆蛋白（PROT）的电泳分析。应用PCR技术扩增了其mtDNA的D-loop区段,利用12种限制性内切酶对其扩增片段进行了RFLP分析;并对2种单倍型的PCR扩增片段进行了序列分析。[结果]同工酶检测出的12个基因座位中,α-GPD＊、GPI＊和PGM＊存在变异,多态基因座位比例及平均杂合度预期值分别为25%和0.092 0。RFLP检测结果表明PCR扩增到约1.6 kb的DNA片段,8种限制性内切酶（AluⅠ、DraⅠ、EcoRⅠ、HaeⅢ、HapⅡ、HinfⅠ、TaqⅠ和XspⅠ）有酶切位点,DraⅠ和TaqⅠ个体间存在变异。将不同酶切类型结果组合后,得到2种单倍型。[结论]根据同工酶检测结果,可以认为乌克兰鳞鲤含有中国鲤与欧洲鲤2种血统;与RFLP分析结果相比,序列分析表明2种单倍型在DraⅠ和TaqⅠ酶切位点以外也存在碱基差异。     

圩猪H-FABP基因多态性分析及其与IMF含量的相关性

 【目的】探究圩猪心脏脂肪酸结合蛋白(H-FABP)基因的多态性,及其与IMF含量的相关性【方法】采用PCR-RFLP(HinfⅠ、HaeⅢ及MspⅠ3种限制性内切酶)分子标记技术,分析了123头圩猪H-FABP基因5'-上游区和第二内含子区的遗传变异情况。【结果】()在5'-上游区：HinfⅠ位点上存在多态性,等位基因H的基因频率为0.6545,表现为中度多态(PIC=0.3500);第二内含子区：HinfⅠ*位点上存在多态性,等位基因B的基因频率为0.7195,表现为中度多态(PIC= 0.3222);Hae Ⅲ位点上也存在多态性,等位基因D的基因频率为0.6301,表现为中度多态(PIC=0.3575);而MspⅠ位点上尚未检测到多态,基因型均为AA型。(2)被测猪群的基因频率和基因型频率都处于Hardy-Weinberg平衡状态(P＞0.05);(3)所检测的基因型对肌内脂肪(IMF)含量影响的趋势为：HH＞Hh＞hh,dd＞Dd＞DD,BB＞Bb＞bb;遗传效应值分别为：4.6918、4.2665、3.7712、4.6124、4.3167、3.8173、4.3042、4.2358、4.1970;(4)对H-FABP基因3个PCR-RFLP多态片段进行克隆测序分析发现,HinfⅠ-RFLP是由于1 324 bp处存在T→C的突变引起,HaeⅢ-RFLP是由于1 811 bp处存在C→G的突变引起,HinfⅠ*-RFLP是由于1 970 bp处存在T→C的突变引起。测序结果与GenBank公布的X98558和Y16180序列有97.9%及98.3%的同源性。【结论】圩猪H-FABP基因5'-上游区和第二内含子区的多态性对其IMF含量有一定影响,但是否可作为研究该基因与圩猪IMF含量相关的重要遗传标记还需做进一步研究。     

圩猪H-FABP基因多态性分析及其与IMF含量的相关性

 【目的】探究圩猪心脏脂肪酸结合蛋白(H-FABP)基因的多态性,及其与IMF含量的相关性【方法】采用PCR-RFLP(HinfⅠ、HaeⅢ及MspⅠ3种限制性内切酶)分子标记技术,分析了123头圩猪H-FABP基因5′-上游区和第二内含子区的遗传变异情况。【结果】(1)在5′-上游区：HinfⅠ位点上存在多态性,等位基因H的基因频率为0.6545,表现为中度多态(PIC=0.3500);第二内含子区：HinfⅠ*位点上存在多态性,等位基因B的基因频率为0.7195,表现为中度多态(PIC=0.3222);Hae Ⅲ位点上也存在多态性,等位基因D的基因频率为0.6301,表现为中度多态(PIC=0.3575);而MspⅠ位点上尚未检测到多态,基因型均为AA型。(2)被测猪群的基因频率和基因型频率都处于Hardy-Weinberg平衡状态(P＞0.05);(3)所检测的基因型对肌内脂肪(IMF)含量影响的趋势为：HH＞Hh＞hh,dd＞Dd＞DD,BB＞Bb＞bb;遗传效应值分别为：4.6918、4.2665、3.7712、4.6124、4.3167、3.8173、4.3042、4.2358、4.1970;(4)对H-FABP基因3个PCR-RFLP多态片段进行克隆测序分析发现,HinfⅠ-RFLP是由于1 324 bp处存在T→C的突变引起,HaeⅢ-RFLP是由于1 811 bp处存在C→G的突变引起,HinfⅠ*-RFLP是由于1 970 bp处存在C→T的突变引起。测序结果与GenBank公布的X98558和Y16180序列有97.9%及98.3%的同源性。【结论】圩猪H-FABP基因5′-上游区和第二内含子区的多态性对其IMF含量有一定影响,但是否可作为研究该基因与圩猪IMF含量相关的重要遗传标记还需做进一步研究。     

葡萄金黄化植原体16SrDNA检测与RFLP分析

[目的]对多种植原体16SrDNA基因序列进行限制性片段长度多态性(RFLP)分析比较,以期区分葡萄金黄化植原体不同亚种,从而为葡萄金黄化植原体的鉴定提供新依据.[方法]用植原体通用引物R16mF2/R16mR1扩增7种不同植原体16SrDNA基因序列,得到约1.5 kb的DNA片段,将此片段克隆到PGM-T载体,并通过酶切鉴定,对重组阳性克隆进行核酸序列测定及同源性分析,利用限制性内切酶XmnⅠ、XspⅠ、TaqⅠ和Rsa Ⅰ对目的片段进行酶切电泳分析.[结果]所扩增2个不同亚种的葡萄金黄化植原体D型和C型序列同源性最高,达99.72;,但利用限制性内切酶可以将上述2个亚种从植原体榆树黄化组中区分.[结论]利用限制性内切酶分析通用引物R16mF2/R16mR1所扩增的基因片段,可以将葡萄金黄化植原体区分.     

胡柚上柑橘衰退病毒的分子检测

胡柚是我国东部地区重要的柑桔栽培品种.近年来,一种以叶片黄化为主要症状的新病害在胡柚种植区暴发流行.通过血清学和分子生物学检测,研究首次从黄化的胡柚叶片中检测到柑橘衰退病毒.系统进化分析表明,分离的CTV CS-7分离物与P09.18、NZRB-TH30等分离物具有较近的进化关系,而与T30等强毒株系有较大的遗传距离,...     

Identification and Preliminary Analysis of the Genetic Diversity of Cenococcum geophilum Fr.

To identify Cenococcum geophilum Fr., estimate their genetic diversity and study the effects on their genetic variation, 27 Chinese C. geophilum isolates from 6 host plant species and 5 French C. geophilum isolates were analyzed using morphological and molecular methods. The universal primers ITS1/ITS4 were used in PCR-RFLP to amplify the rDNA internal transcribed spacer （ITS） of tested C. geophilum isolates. The amplified products were digested with EcoR Ⅰ, Hinf Ⅰ, and Mbo Ⅰ, and the digested fragments of PCR products showed that there were obvious differences. A random primer （5′-CGCACCGCAC-3′） was employed in RAPD to amplify the genomic DNA of C. geophilum, and 19 detectable and reliable DNA bands of 300-2000 bp size were observed. According to the number, position, and strength of the DNA bands in agarose gel, the genetic distance and the genetic similarity among C. geophilum isolates were calculated using the PopGen Ver. 1.31 dendrogram analysis software. A phylogenetic tree was constructed based on the genetic distance by the Neighbor-Joining/UPGMA in PHYLIP. The results suggest the high level of genetic diversity among C. geophilum isolates from the same or different hosts. The effects of geographical factors or host plant species on C. geophilum genetic variation are not obvious.     

浙江省地方鸡种禽白血病毒抗原检测与部分分离株GP85基因序列分析

为了解浙江地区地方品种鸡中J亚群禽白血病病毒(subgroup J avian leukosis vrius,ALV-J)的感染情况与流行毒株的分子特征,对浙江省部分地方品种鸡体内ALV的p27抗原进行了检测,从疑似感染鸡群中检测分离到5株 ALV-J,并对其GP85基因进行PCR分子克隆和序列分析。研究结果显示:在检测的19个地方鸡品系中,所有品系的鸡样本都呈现抗原阳性,其中101系的抗体阳性率最高,母鸡阳性率为40.48%,公鸡阳性率为16.54%;126系次之,母鸡阳性率为28.87%,公鸡阳性率为3.30%;171系抗体阳性率最低,其母鸡阳性率仅为4.08%,公鸡的感染率为0。为了解地方鸡群中ALV-J的遗传变异,对分离到的5株ALV-J的GP85基因进行了分子克隆和序列分析。结果表明,5个分离毒株的GP85基因大小均为924 bp,与预期一致;本研究样品序列之间的核苷酸同源性为90.8%~98.5%,与原型毒株HPRS103核苷酸相似性为90.3%~97.0%,与国内其他分离株的同源性为86.5%~99.0%。分离株与福建(FJ201308株)和广东(WF13株)分离株的同源性最高。结果表明:浙江省大部分地方品种鸡都不同程度感染ALV-J,而且分离毒株已经发生了不同程度的变异,提示我们应加强浙江省地方品种鸡ALV的净化工作。     

马桑根瘤内生菌纯培养物的分离、回接及其生物学特性

多次采用根瘤切片法直接从野生的马桑根瘤中分离内生菌纯培养物均未获成功;但用同样方法从温室里人工接种形成的马桑根瘤中却分离到大量纯培养物。其中273株经盆栽回接后发现有24株能侵染结瘤;少数菌株还通过半固体斜面和珍珠岩盆栽回接成功。对10株纯培养物表型特性的研究表明,它们均具有Frankia的形态和培养特征;生理类型除有A、B两型外,尚出现有一类A、B混合型,其中凡属B型菌株的均能侵染结瘤,A型则不能,两株A、B混合型中有1株能结瘤,另1株却不能;碳、氮源利用特性和其它Frankia基本相似;细胞壁组分既有Ⅲ型也有Ⅱ型;全细胞鉴别性糖大多为木糖和半乳糖,少数菌株只含有半乳糖或木糖,或含有半乳糖、木糖和阿拉伯糖。DNA中G+C mol%为65%～74%。     

攀西地区葛藤根瘤菌的RFLP遗传多样性

利用16S rDNA PCR-RFLP和16-23S IGS PCR-RFLP技术对分离自四川攀枝花的43株葛藤根瘤菌进行了遗传多样性研究。供试菌株的16S rDNA用HaeⅢ、MspⅠ、HinfⅠ和TaqⅠ酶切后具有16种遗传图谱类型。16S-23S rDNA IGS PCR-RFLP分析结果表明,在53%的相似性水平上,供试菌株与参比菌株分为两个分支,在81%的相似水平上所有菌株分为13个群。     

大丽轮枝菌Nit突变体产生及其营养亲和性测定

从DNA限制性酶切多态性(RFLPs)的A组和B组中选用了具代表性的7个大丽轮枝菌菌系作营养亲和性测定.病菌分别接种在含氯酸钾15～25g/l的基本培养基(MM)、梅干培养基(PLA)、玉米粉琼脂培养基(CMA)和马铃薯葡萄糖培养基(PDA)上,从中获得了41个不能还原利用硝酸钠作为唯一氮源正常生长的突变体(Nit).Nit突变体以PDA和PLA含氯酸钾20～25g/l的两种培养基上发生频率较高.根据对不同氮源利用生长情况,获得了Nit突变体5种生理表现型.以Nit1居多(50%～100%),其次为NitM(0～50%).表现型互补的Nit1与NitM突变体营养亲和性测定结果表明,测试菌系可划分为VCG01和VCG02两个营养亲和群,分别含RFLPsA组的4个菌系和B组的3个菌系.     

Genetic Evolution Analysis on Wild Isolates of Citrus Tristeza Virus Originated in China Based on Coat Protein Genes Sequences

The coat protein （CP） genes were cloned and sequenced from viral particles of 11 isolates of citrus tristeza virus （CTV） collected from wild citrus plants in China and 4 Chinese isolates from cultivated sweet orange and pummelo varieties, respectively. By analyzing and comparing the nucleotide and amino acid sequences of CP genes, the 11 wild CTV isolates were found over 92% identical with 4 Chinese CTV isolates and 21 exotic CTV isolates from cultivated citrus. From 91 to 100% of the CTV CP gene sequences in wild type citrus plants were generally well conserved. Genetic evolution analysis indicated that the GC% of the CP gene was less than AT%, and more transition were found in the CP genes than transversion with the transition/transversion ratio ranging from 6.3 to 7.0 among species. The substitution frequency was the highest at the third codon, followed by the first and second codon. The ratio of non-synonymous mutations （du） to synonymous mutations （ds） was far lower than 1, suggesting that the CP gene might have experienced purifying selection in the evolution. Phylogenetic analysis revealed that the 11 CTV isolates in Chinese wild type citrus belonged to different phylogenetic clusters, and shared higher homology and closer relationships with other cultivated citrus CTV isolates from different countries, which indicated complicated genetic relationships among the CTV isolates. In addition, CTV isolates with similar biological characteristics usually located into the same clusters. Therefore, the conclusion was drawn that pathogenicity was critical to evolution and origin of CTV.     

运用PCR-RFLP标记检测南瓜疫病菌

用 1对特异引物对南瓜疫霉菌 (Phytophthora capsici)及疫霉属 (Phytophthora)部分真菌和常见土传真菌12个种的 14个菌株的 18s r DNA(即 Small Subunit Ribosom al DNA)进行扩增 ,用 4种限制性内切酶 (Eoo R 、Hae 、Hha 、Hinf )酶切 PCR扩增产物 ,分析各菌株间的 DNA限制性片段多态性 ,首次建立了南瓜疫霉菌的PCR- RFL P检测程序。并运用该 PCR- RFL P检测程序对染病南瓜植株进行检测 ,成功地在南瓜植株发病茎病健交界处、发病叶病健交界处、发病果病健交界处、接种 2 4 h的叶和接种 P.capsici 12 h的茎上快速、准确地检测到了南瓜疫病菌的存在。     

Expressing p20 hairpin RNA of Citrus tristeza virus confers Citrus aurantium with tolerance/resistance against stem pitting and seedling yellow CTV strains

The Citrus tristeza virus(CTV) uses 3 silencing suppressor genes, p20, p23 and p25, to resist the attacks from its Citrus hosts. Inactivating these genes is therefore obviously a potential defensive option in addition to the current control strategies including aphid management and the use of mild strain cross protection. In this study, we cloned partial DNA fragments from the three genes, and used them to construct vectors for expressing hairpin RNAs(hp RNAs). To facilitate the formation of hp RNAs, the constructs were introduced in a loop structure. Following transformation of sour orange(Citrus aurantium) with these constructs, 8 p20 hp RNA(hp20) and 1 p25 hp RNA(hp25) expressing lines were obtained. The 7 hp20 transgenic lines were further characterized. Their reactions to CTV were tested following inoculation with CT14 A and/or TR-L514, both of which are severe strains. Results showed that 3 lines(hp20-5, hp20-6 and hp20-8) were completely resistant to TR-L514 under greenhouse conditions for no detectable viral load was found in their leaves by PCR. However, they exhibited only partial suppression of TR-L514 under screen house conditions since the virus was detected in their leaves, though 2 months later compared to non-transgenic controls. Further tests showed that hp20-5 was tolerant also to CT14 A under screen house conditions. The growth of hp20-5 was much better than others including the controls that were concurrently challenged with CT14 A. These results showed that expressing p20 hp RNA was sufficient to c onfer sour orange with CTV resistance/tolerance.