小麦抗白粉病基因Pm4b的RGA分析

为克隆抗性基因和发展Pm4b的特异分子标记奠定基础。利用10对RGA引物,对小麦抗白粉病基因的一些载体品种(系)进行扩增,将引物对R11F/R11R从Pm4b基因的载体品种VPM中扩增出的稳定多态性条带回收、克隆、测序,获得与小麦Pm4b基因的相关抗病基因的同源片段,并对不同的小麦Pm基因载体品系作了检测分析。该稳定多态性条带全长1 321 bp。序列分析表明这个片段属于RGA类序列。用该标记检测小麦不同Pm基因载体品种(系),发现该多态性片段仅出现在Pm4b基因载体品种中。该研究可为分离抗性基因和发展Pm4b的特异分子标记奠定基础。     

家蚕荧光茧色分子标记初探

为了获得家蚕荧光茧色基因的分子标记,以家蚕的荧光品种C408黄和C408紫为材料,采用400多个RAPD随机引物筛选分子标记,获得了与家蚕紫荧光茧色有关的1个分子标记CFP-01859.并通过设计特异引物转换成SCAR标记验证,证明获得的标记真实、可靠,并对该分子标记的片段进行了克隆和测序.     

大麻性别相关AFLP分子标记筛选

利用扩增片段长度多态性(amplified fragment length polymorphism,AFLP)分子标记,用8个EcoRⅠ-NNN和8个MseⅠ-NNN组成64对引物,对大麻10个品种混合组成的雌性、雄性植株基因池进行筛选,并将筛选到的引物在此10个品种中进行验证,引物E-ACT/M-CTA在10个品种的雄株中均扩增出1条特异条带,雌株中均没有此带,对此引物扩增得到的特异性条带回收、克隆、测序,获得1条大小为348 bp的雄性特异性条带,得到的序列进行GenBank序列比对,数据库中没有与此特异条带同源的序列.该条特异条带可作为分子遗传标记用于大麻早期性别鉴定的参考.     

利用RGA-PCR方法进行水稻抗瘟基因分子标记

用28对RGA引物对LTH近等基因系品种进行PCR扩增，其中11对引物扩增出特异性条带。将扩增到的33个特异性片段回收并进行重扩增，有11个片段产生单一条带。选择2个片段HS-1和HS-19进行探针标记。经Southern杂交发现。探针HS-1在含有Pi—ta^2抗瘟基因品种F-128—1、NO4中有特异杂交信号，表明该片段可能与抗瘟基因Pi—ta^2连锁或是其一部分。对特异性片段HS-1进行克隆、测序，全长为478bp，与Mago等从水稻中克隆的一个抗病基因同源序列RGA29有95％同源性。     

大麻性别相关AFLP分子标记筛选

利用扩增片段长度多态性(amplified fragment length polymorphism,AFLP)分子标记,用8个EcoRⅠ-NNN和8个MseⅠ-NNN组成64对引物,对大麻10个品种混合组成的雌性、雄性植株基因池进行筛选,并将筛选到的引物在此10个品种中进行验证,引物E-ACT/M-CTA在10个品种的雄株中均扩增出1条特异条带,雌株中均没有此带,对此引物扩增得到的特异性条带回收、克隆、测序,获得1条大小为348bp的雄性特异性条带,得到的序列进行GenBank序列比对,数据库中没有与此特异条带同源的序列.该条特异条带可作为分子遗传标记用于大麻早期性别鉴定的参考.     

小麦抗叶锈近等基因系TcLr38的SRAP-SSR(eSSR)分析

小麦抗叶锈基因Lr38在我国高抗叶锈病,直到目前该基因的分子标记开发较少,开发其分子标记对于该基因的研究与利用具有重要意义。利用594对SRAP-SSR(eSSR)引物组合对以Thatcher为背景小麦抗叶锈近等基因系材料TcLr38和Thatcher进行PCR扩增。引物组合ARBI8-Xcwem8R和ARBI2-Xgwm497F在TcLr38中分别扩增出300和400bp多态性条带。利用47个小麦抗叶锈近等基因系进一步检测,引物ARBI8-Xcwem8R仅在TcLr38中扩增出特异条带。经TcLr38×Thatcher F2代分离群体验证,该标记与Lr38遗传距离较远。对该片段克隆测序,片段长度为277bp,BLAST比对与GenBank中所收录序列无相似性,该片段为与Lr38相关的新的序列。     

甘薯抗茎线虫病基因SCAR标记辅助育种初探

用已获得的与抗甘薯茎线虫病基因连锁的RAPD标记OPD01-700引物对高抗亲本徐781和高感亲本徐薯18的F1分离群体的161个品系进行PCR扩增.根据该标记扩增结果,利用Mapmaker3.0软件计算遗传距离,得出此标记与甘薯茎线虫病基因的连锁距离为19.4 cM.对RAPD标记OPD01-700片段进行克隆、测序,得到长度为689 bp的DNA序列,将该序列命名为OPD689.根据测序结果,设计1对特异引物,进行特异性扩增,成功地将OPD689标记转化为SCAR标记.将SCAR标记在7个高抗品系和13个高感品系进行初步验证应用,其结果与田间鉴定结果基本一致.初步建立了甘薯抗茎线虫病育种分子标记辅助选择技术.     

小麦抗白粉病基因Pm23分子标记的初步鉴定

根据植物抗病基因的保守结构,合成7对特异引物,用感病品种Chanceller作对照,对12个含不同抗白粉病基因的小麦品系进行PCR分析,结果只有1对引物(3LR 3LF)在Pm23的载体品系中扩增出稳定的多态性片段,对该片段进行回收、克隆、测序,全长为253bp。经同源性分析发现,该特异性片段与大麦Ty3-gypsy类反转录转座子基因部分序列有87%的同源性,属于反转录转座子类标记。     

小麦抗叶锈病基因Lr45的AFLP分子标记

 利用AFLP技术对小麦抗叶锈基因Lr45进行了标记，从60对AFLP引物中筛选出2对在亲本及TcLr45×Thatcher F2抗感群体间揭示多态性的引物P-AGG/M-GAG和P-ACA/M-GGT。其扩增片段为261 bp和105 bp，2个标记与Lr45的遗传距离分别为0.6 cM和1.3 cM。测序比较261 bp片段与大麦属Vulgare HotrI基因部分序列同源性达86%，105 bp片段与一粒小麦磷脂酰丝氨酸脱羧酶基因部分序列同源性高达96%。2个测序片段均包含开放阅读框（ORF）序列。     

小麦抗白粉病基因Pm4三个STS标记的实用性分析

根据已报道的序列,合成了3对STS引物4aF + 4aR、4a + 4b和4G + 4I ,对2 4个含已知抗白粉病基因的品种、3个含未知抗白粉病基因的品种和4个感病品种进行了分析。结果表明,4G + 4I和4aF + 4aR 2对引物,扩增产物稳定,均能够扩增出特异性较强、易于检测的目标片段STS4 70 和STS4 10 ,并且标记STS4 70 与Pm4a基因完全连锁。这2个STS标记联合使用,能够准确地检测Pm4基因,作为分子标记辅助选择手段,在小麦抗白粉病育种中具有重要的应用价值。     

抗浓核病毒中国株家蚕品系中肠羧酸酯酶活力变化和基因表达差异的研究

 【目的】探讨家蚕中肠羧酸酯酶活力变化及羧酸酯酶基因表达差异与家蚕抗浓核病毒之间的关系，阐明其抗性的分子机理。【方法】以易感浓核病毒中国株家蚕品系华八和完全抗性品系BC8（华八的近等基因系）为材料，用BIO-TEK SYNERGY测定经口接种病毒(以下简称接种)后12 h、36 h、72 h 2个品系中肠的羧酸酯酶活力，并用实时荧光定量PCR研究接种后12 h、36 h、72 h中肠羧酸酯酶基因的表达差异。【结果】接种后12 h中肠羧酸酯酶活力BC8接种组分别是BC8对照组、华八接种组和华八对照组的3.28倍、2.26倍和3.02倍,差异达到极显著水平（P＜0.01）其它时间段的供试组之间无统计学差异；接种后12 h中肠羧酸酯酶基因的相对表达量BC8接种组分别是华八接种组、华八对照组、BC8对照组的17.714倍、21.76倍和15.09倍,差异达到极显著水平（P＜0.01），其它时间段的供试组之间也无统计学差异。【结论】接种后12 h抗性品系BC8中肠羧酸酯酶活力升高及中肠羧酸酯酶基因表达水平升高可能与家蚕品系是否有抗性基因(nsd/nsd)有关,也与浓核病毒中国株的感染刺激有关；抗性品系BC8中肠羧酸酯酶活力升高的分子基础可能是羧酸酯酶基因表达水平的改变。     

A Study on the Activity of Carboxylesterase and the Differential Expression of Its Gene in the Midguts of Bombyx mori Resistant to BmDNV-Z

This study was to discuss the relationship among the change in the activity of Bombyx mori carboxylesterase （BmCarE） in the midguts, the differential expression of BmCarE gene （bmcare） in the midguts, and the ability of Bombyx mori resistant to densonucleosis virus （BmDNV）, and to elucidate the molecular mechanism of resistance to BmDNV-Z. With two silkworm strains, HUABA, which is susceptible to BmDNV-Z, and BC8 （a near isogenic line of HUABA）, which is completely resistant to the same virus, as materials, the activity of BmCarE in the midgut was determined by Bio-Tek Synergy, and the differential expression of bmcare between the two strains was investigated by real-time fluorescence quantitative PCR, both at 12, 36, and 72 h post oral inoculation of the two strains with virus （hereafter referred as inoculation）. While the activity of BmCarE in the midguts of BC8 inoculation group at 12 h post inoculation was higher than that in the BC8 control group, the HUABA inoculated group, and the HUABA control group by 3.28, 2.26, and 3.02 times, respectively, with the difference being highly significant （P 〈 0.01）, there was no statistical difference among the other groups. The relative expression level of bmcare in the midguts of BC8 inoculation group at 12 h post inoculation was higher than that in the BC8 control group, the HUABA inoculation group, and the HUABA control group by 17.714, 21.76, and 15.09 times, respectively, with the difference being highly significant （P 〈 0.01）, and there was no statistical difference among other groups. The elevation of BmCarE activity and expression level of bmcare in the resistant strain at 12 h post inoculation may relate to the resistant gene （nsd/nsd） and the stimulation of BmDNV-Z. The molecular basis for the elevation of BmCarE activity in the resistant strain BC8 may be the change in the expression level of bmcare.     

Studies on the Mutant Systems of the Bombyx mori Gene Bank

Through over ten years of study, more than 1 000 genetic materials including mutant genes,chromosomal variation strains and special genetic materials of Bombyx mori, Linnaeus, collected, introduced or created since 1940s especially late 1980s, have been sorted out and put in order. After identifications and genetic analyses of their morphological, physiological and biochemical characters, the silkworm gene bank was constructed and the preservation system was perfected, and more than 600 silkworm strains were kept in this gene bank. The preserved silkworm mutant genes have covered more than 90% of existent ones across the world, in which, more than 100 are rare and precious mutant genes, and over 60 mutant genes were found and studied for the first time. Through hybrid analyses, linkage tests and three-point gene location tests, a perfect linkage retrieval labeling system of silkworm was established, which included 230 marker genes covering all the 28 linkage groups of Bombyx mori. The gene location system (composite system of recessive genes) of different linkage groups was set up. The intergenic complementation of mutant egg color and third type of maternal heredity egg color have been found, and indicated that the epistatic effect of mutant gene of white egg is universal. Twenty eight independent near isogenic lines murked with morphological mutation gene have been created and a series of novel breeding materials possessing great potential for application such as high feeding efficiency, special sex markers, natural colored silk, resistance to disease, wider feeding range and adjustable parthenogenesis, etc., have been developed. The sustainable maintenance and management technique system of silkworm gene resources were well established.     

粳稻抗虫转基因保持系的研究

利用基因枪转化法,以优质粳稻保持系早花二B为受体,获得了含有GNA和Hyg基因的转基因植株。对T2产生的6个纯合株系进行多代潮霉素筛选、PCR分子检测及稻飞虱接种鉴定,表明标记基因在受体中稳定遗传,并高效表达,且一经纯合不再分离;而目的基因表达效果不一样,只有T-10(克隆号A5-32)表达效果最好,其抗虫性达到中抗(MR)以上水平,比受体抗性(S)明显提高。将转基因保持系与不育系早花二A回交,获得的转基因不育系高抗潮霉素,且抗性也完全纯合,表明转基因保持系的抗性基因已转化到不育系中,并得到高效表达。     

10株微孢子虫Hsp70基因克隆及系统发育分析

对10株不同来源的微孢子虫Hsp70基因部分序列进行扩增,并进行了系统发育分析,结果表明:所设计的引物可以有效地扩增出10株家蚕等昆虫微孢子虫Hsp70基因中1136 bp大小的片段。遗传距离矩阵和系统发育分析表明,家蚕微孢子虫与野外昆虫微孢子虫的亲缘关系密切,再次从分子水平上证明了家蚕病原微孢子虫来自环境中的野外昆虫微孢子虫的可能性;不同微孢子虫在不同寄主中的寄生生活是一个相互选择和适应的过程;微孢子虫Hsp70基因具有遗传多样性;家蚕微孢子虫是一个种复合体。     

广西家蚕僵病流行趋势及其主要病原遗传规律研究

【目的】摸清广西家蚕僵病发生流行规律,研究病原特性及遗传规律,为精准防控家蚕僵病提供科学依据。【方法】以2008—2021年广西家蚕僵病发病原始数据为基础,分析广西家蚕僵病的发病规律。收集广西五大蚕区（桂中、桂南、桂西、桂西北和桂东南）的病蚕、病虫及生物防控白僵菌株,经显微形态鉴定和产孢测定后采用滤纸接触法测试其对家蚕的致病力;基于ITS4/ITS5引物进行PCR扩增,并将双向测序结果输入GenBank进行BLAST比对分析;根据ISSR-PCR扩增结果以Quantity One绘制电泳模式图,使用NTsys计算遗传相似系数并进行UPGMA聚类分析,同时以PopGene32对供试材料的遗传多样性指数进行分析。【结果】 2008—2021年广西家蚕僵病发病率整体上呈波动下降趋势,连续14年的平均发病率为5.19%。5月是广西家蚕僵病的发病率高峰,平均发病率为13.37%;其次是4月和10月,对应的发病率分别为7.91%和6.87%。山区地形的家蚕僵病发生率普遍高于平缓丘陵地区,其中,丘陵蚕区的家蚕僵病发病率排序为桂中（13.55%） >桂西北（12.66%） >桂南（11.56%） >桂西（11.05%） >桂东南（9.53%）,山地蚕区的家蚕僵病发病率排序为桂中（18.91%） >桂西北（17.96%） >桂西（16.01%） >桂西（14.90%） >桂东南（11.61%）。广西家蚕僵病病原包括白僵菌属、曲霉属、拟青霉属和虫草菌属,其中球孢白僵菌（Beauveria bassiana）为主要病原,占比达86.67%,且白僵菌ITS序列高度保守,序列相似性在97.83%~99.83%。不同白僵菌株对家蚕的致病力表现为崇左白僵菌株（农药）的72 h累计死亡率达100.00%,明显高于蚕区僵蚕菌株（8.89%~93.33%）。筛选出的10条ISSR引物从50株菌株样本中扩增出152条清晰条带,其中多态位点147个,多态百分数为87.5%~100.0%; 50株菌株样本的Nei's基因多样性指数（H）为0.1740~0.3257,Shannon信息多样性指数（I）为0.2840~0.4880,均表现出极高的遗传多样性;基于遗传距离构建的UPGMA系统发育进化树显示,桂南、桂西北、桂东南、桂中等蚕区的病蚕白僵菌株与农药源白僵菌株存在非常近的亲缘关系。【结论】广西家蚕僵病危害高峰期为5月,球孢白僵菌是最主要的病原菌,且ITS序列高度保守。不同来源白僵菌对家蚕致病力的排序为农药源白僵菌株>松林白僵菌株>蚕区僵蚕菌株,但三者相互间存在非常高的基因关联性,提示广西家蚕僵病的病原遗传背景复杂,且蚕桑主产区应慎用白僵菌农药。     

四种不同植物病原真菌与多菌灵抗药性相关基因突变的比较

克隆了小麦赤霉病菌（Fusarium graminearum）、油菜菌核病菌（Scherotinia sclerotiorum）、辣椒炭疽病菌（Cal-letotrichum gloeosporiodies）和番茄灰霉病菌（Botrytis cinerea）4种病原菌的9个菌株的β－微管蛋白基因、进而与典型模式菌粗糙麦孢霉（Neurospora crassa）进行序列比较，结果表明，4种病原真菌β－微管蛋白序列与粗糙表孢霉具高度同源性；油菜菌核病菌、辣椒炭疽病菌和番茄灰霉病菌的β－微管蛋白198位氨基酸由Glu突变为Ala，是导致上述病原菌产生对多菌灵（MBC）抗药性的主要原因；突变位点和突变类型与其他抗多菌灵真菌一致，且与乙霉威（NPC）之间存在明显负交互抗性。但小麦赤霉病MBC^S和MBC^R菌株的β－微管蛋白序列完全一样，且与NPC之间不存在负交互抗性，有关小麦赤霉病菌产生抗药性的机制有待于进一步的研究。     

Detection of antimicrobial resistance and virulence-related genes in Streptococcus uberis and Streptococcus parauberis isolated from clinical bovine mastitis cases in northwestern China

The objectives of this study were to investigate antimicrobial resistance of Streptococcus uberis and Streptococcus parauberis isolated from cows with bovine clinical mastitis in China and to examine the distribution of resistance- and virulence-related gene patterns. Antimicrobial susceptibility was determined by the E-test. Genes encoding antimicrobial resistance and invasiveness factors were examined by PCR. A total of 27 strains were obtained from 326 mastitis milk samples. Streptococcus parauberis isolates (n=11) showed high resistance to erythromycin (90.9%), followed by tetracycline (45.5%), chloramphenicol (36.4%) and clindamycin (27.3%). Streptococcus uberis isolates (n=16) were highly resistant to tetracycline (81.3%) and clindamycin (62.5%). Both species were susceptible to ampicillin. The most prevalent resistance gene in S. uberis was tetM (80.0%), followed by blaZ (62.5%) and ermB (62.5%). However, tetM, blaZ, and ermB genes were only found in 27.3, 45.5, and 27.3%, respectively, of S. parauberis. In addition, all of the isolates carried at least one selected virulence-related gene. The most prevalent virulence-associated gene pattern in the current study was sua+pauA/skc+gapC+hasC detected in 22.2% of the strains. One S. uberis strain carried 7 virulence-associated genes and belonged to the sua+pauA/skc+gapC+cfu+hasA+hasB+hasC pattern. More than 59.3% of analysed strains carried 4 to 7 virulence-related genes. Our findings demonstrated that S. parauberis and S. uberis isolated from clinical bovine mastitis cases in China exhibited diverse molecular ecology, and that the strains were highly resistant to antibiotics commonly used in the dairy cow industry. The data obtained in the current study contribute to a better understanding of the pathogenesis of bacteria in mastitis caused by these pathogens, and the findings are relevant to the development of multivalent vaccines and targeted prevention procedures.     

云南蚕区家蚕品种资源对家蚕核型多角体病毒的抗性评价分析

[目的]全面掌握云南蚕区家蚕品种资源的抗家蚕核型多角体病毒(BmNPV)能力,为挖掘具有特色的家蚕抗病材料及培育适应当地的抗病品种提供参考.[方法]采用三龄起蚕经口添食相同浓度病毒、逐日调查存活率的方法,对200个家蚕品种(品系)进行BmNPV抗性评价和筛选;并通过接种后每日存活数、各发育时期存活率等指标分析云南蚕区家蚕品种资源对BmNPV的抗性水平、发病死亡规律、不同抗性品种的发病死亡时期及同一品种不同品系间抗性差异.[结果]云南蚕区家蚕品种资源中抗BmNPV的品种有731、795、854B、872A、966B、B黄肉色茧、P50、山河B、选二甲白和竹印,感病品种包括955、242A、242B、963B、DW3、锦秀A、锦秀B、日、野乙和云夏A油.各抗病品种和感病品种首次出现死亡差异的时间截点分别是接种后96和48 h,二者相差48 h;部分抗病品种在秋季对BmNPV的抗性水平低于春季;同一家蚕品种A系和B系的抗病性差异不显著(P>0.05).[结论]云南蚕区家蚕品种资源中大多数品种的抗BmNPV能力属于中等水平,其中P50为BmNPV抗性最强品种.对未知品种进行抗BmNPV测定时,可选择接种后168 h作为抗性评价的时间截点.     

11个优质小麦品种对小麦白粉病抗性的初步鉴定

于2009年、2010年连续2 a采用自然苗圃法对郑州市推广种植的优质小麦品种进行了白粉病抗性鉴定.在供试的11个小麦品种中,无白粉病免疫及高抗品种,其中郑麦366在2009年、2010年的平均病情指数分别为42.27、15.18,均极显著低于对照品种郑麦9023,其相对抗病指数分别为0.56、0.70,属于中抗品种....