首次发现我国柑橘小实蝇沃尔巴克氏体的共生

沃尔巴氏体(Wolbachia)是广泛分布于节肢动物体内的一类共生细菌,它们可以调控宿主的生殖活动.本研究利用沃尔巴克氏体wsp基因的一对通用引物(81F,691R),成功地从我国柑橘小实蝇雄成虫的总DNA中扩增到一段400bp左右的wsp基因片段,通过wsp基因的特异性扩增首次证实了沃尔巴克氏体在我国柑橘小实蝇雄虫体内的共生.     

草间钻头蛛共生菌多样性测定及沃尔巴克氏体感染对宿主发育历期和性比的影响

为了解草间钻头蛛Hylyphantes graminicola体内共生菌的组成及共生菌对宿主的影响,通过高通量测序技术确定其体内的优势共生菌,采用常规PCR法对草间钻头蛛进行优势共生菌的感染检测,并研究了优势共生菌感染对草间钻头蛛子代的发育历期和性比的影响。结果表明:经高通量测序细菌16S r DNA的V3、V4区,确定草间钻头蛛的优势共生菌为沃尔巴克氏体Wolbachia和Cardinium。167头被检测蜘蛛中,Cardinium的感染率为100.00%,沃尔巴克氏体的感染率为38.92%。感染沃尔巴克氏体的草间钻头蛛F1代雌蛛的2龄期、3龄期、4龄期和总历期均极显著低于未感染的草间钻头蛛,感染沃尔巴克氏体的草间钻头蛛F1代雌蛛1龄期显著低于未感染的F1代个体,感染和未感染沃尔巴克氏体的草间钻头蛛F1代雌蛛的卵期和5龄期均无显著差异。感染沃尔巴克氏体后,草间钻头蛛F1代雄蛛的1龄期和总历期极显著缩短,2龄期、3龄期和5龄期显著缩短,而卵期和4龄期与未感染沃尔巴克氏体的F1代雄蛛之间无显著差异。另外,沃尔巴克氏体感染极显著提高了草间钻头蛛的子代性比。     

灰飞虱体内Wolbachia的检测及三种稻飞虱Wolbachia的wsp基因差异分析

采用PCR方法对灰飞虱感染Wolbachia情况进行检测,并对Wolbachia的wsp基因进行序列测定和系统发育分析,以明确各地区Wolbachia的差异及三种稻飞虱体内Wolbachia的差异。结果表明,12省份21地区灰飞虱群体Wolbachia平均感染率达到96.41%。各地灰飞虱体内Wolbachia不存在明显的地理种群分化。与褐飞虱及白背飞虱体内Wolbachia的wsp序列对比,灰飞虱与白背飞虱的序列一致,而与褐飞虱存在较大差异(相似性83.39%),处于不同的系统进化簇。表明感染白背飞虱与灰飞虱的Wolbachia处于相同株系,而感染褐飞虱的Wolbachia处于另一株系。     

两种金小蜂体内Wolbachia的wsp基因分子检测及序列分析

采用Wolbachia的通用引物及A和B大组特异性引物对蝶蛹金小蜂Pteromalus puparum和丽蝇蛹集金小蜂Nasonia vitripennis体内Wolbachia的wsp基因进行PCR扩增及序列测定，并对测定的序列进行了同源性比较和基因特征分析。结果表明：蝶蛹金小蜂和丽蝇蛹集金小蜂均被A和B两个大组的Wolbachia复合感染；同种寄生蜂的雌蜂和雄蜂的wsp基因片段序列完全一致。采用通用引物从蝶蛹金小蜂中扩增出Wolbachia的wsp基因片段序列的长度为540bp，属于B大组中Pip组，而从丽蝇蛹集金小蜂中扩增出Wolbachia的wsp基因片段序列的长度为558bp，属于A大组中Uni组。用A-Wolbachia引物从蝶蛹金小蜂和丽蝇蛹集金小蜂中扩增出的wsp基因片段序列长度为548bp，同源性达99．8％；而用B-Wolbachia引物从两者中扩增的两条wsp基因片段序列长度分别为424bp和439bp同源性达87．5％．     

Detection and characterisation of strong resistance to phosphine in Brazilian Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

As failure to control Rhyzopertha dominica (F.) with phosphine is a common problem in the grain-growing regions of Brazil, a study was undertaken to investigate the frequency, distribution and strength of phosphine resistance in R. dominica in Brazil. Nineteen samples of R. dominica were collected between 1991 and 2003 from central storages where phosphine fumigation had failed to control this species. Insects were cultured without selection until testing in 2005. Each sample was tested for resistance to phosphine on the basis of the response of adults to discriminating concentrations of phosphine (20 and 48 h exposures) and full dose-response assays (48 h exposure). Responses of the Brazilian R. dominica samples were compared with reference susceptible, weak-resistance and strong-resistance strains from Australia in parallel assays. All Brazilian population samples showed resistance to phosphine: five were diagnosed with weak resistance and 14 with strong resistance. Five samples showed levels of resistance similar to the reference strong-resistance strain. A representative highly resistant sample was characterised by exposing mixed-age cultures to a range of constant concentrations of phosphine for various exposure periods. Time to population extinction (TPE) and time to 99.9% suppression of population (LT(99.9)) values of this sample were generally similar to those of the reference strong-resistance strain. For example, at 0.1, 0.5 and 1.0 mg L(-1), LT(99.9) values for BR33 and the reference strong-resistance strain were respectively 21, 6.4 and 3.7 days and 17, 6.2 and 3.8 days. With both strains, doubling phosphine concentrations to 2 mg L(-1) resulted in increased LT(99.9) and TPE. High level and frequency of resistance in all population samples, some of which had been cultured without selection for up to 12 years, suggest little or no fitness deficit associated with phosphine resistance. The present research indicates that widespread phosphine resistance may be developing in Brazil. Fumigation practices should be monitored and resistance management plans implemented to alleviate further resistance development.     

Detection and characterization of phytoplasmas in diseased stone fruits and pear by PCR-RFLP analysis in Turkey

During the late summer-early autumn of 2002, surveys were carried out in Turkey to determine the presence of phytoplasma diseases in fruit trees. Phytoplasmas were detected and characterized by PCR-RFLP analysis and TEM technique in stone fruit and pear trees in the eastern Mediterranean region of the country. Six out of 24 samples, including almond, apricot, peach, pear and plum, gave positive results in PCR assays. RFLP analysis usingSspI andBsaAI enzymes of PCR products obtained with primer pair f01/r01 enabled identification of the phytoplasmas involved in the diseases. Stone fruit trees, including a local apricot variety (‘Sakıt’) and a pear sample, were found to be infected with European stone fruit yellows (ESFY, 16SrX-B) and pear decline (PD, 16SrX-C) phytoplasmas, respectively. This is the first report in Turkey of PD phytoplasma infecting pear and of ESFY phytoplasma infecting almond, apricot, myrobalan plum and peach; ESFY phytoplasma infecting Japanese plum was previously reported. http://www.phytoparasitica.org posting July 21, 2005.     

白菜型油菜BraSAUR基因家族鉴定及其表达分析

SAUR(Small auxin-up RNA)是生长素早期响应逆境胁迫的基因,本文研究白菜型油菜全基因组中SAUR家族的信息,分析了该家族成员的基本特征。以强抗寒性白菜型冬油菜品种陇油7号（L7）和弱抗寒性冬油菜品种陇Lenox（X）为试验材料,采用低温和干旱处理,应用荧光定量技术分析不同基因在不同品种中的表达特性,筛选差异表达基因,为研究生长素早期应答基因调控白菜型冬油菜生长点发育机理提供支撑。结果表明：白菜型油菜的BraSAUR基因共有142个,在10条染色体中不对称分布,主要分布在2、3号染色体上,基因长度较短,且大多数基因没有内含子。qRT-PCR结果表明,低温处理后,与CK相比,在两个品种的叶片中,Bra029452的表达量变化趋势不同,24 h时在L7中的表达量是X的24倍,在生长点中,Bra010501在L7中24 h时表达量达到CK的4倍,而在X中是先增加后降低的趋势。模拟干旱胁迫后,Bra029452在L7的叶片中的表达量均显著高于CK,在X中则是逐渐降低,在L7的生长点中1 h和24 h表达量均高于CK,但在X中则表现为先降低后升高。低温胁迫和干旱胁迫条件下,Bra029452基因表达量在强抗寒性油菜品种L7的叶片及生长点中均逐渐升高,可推断该基因同时参与白菜型冬油菜耐受低温、干旱的调控过程。     

小菜蛾对阿维菌素的抗性机制及交互抗性研究

用叶片药膜法研究了阿维菌素抗性小菜蛾 Plutella xylostella （L.）品系 对常用药剂的交互抗性谱以及增效醚（PB）和磷酸三苯酯（TPP）的增效作用。小菜蛾对阿 维菌素与高效氯氰菊酯、溴氰菊酯、氰戊菊酯和联苯菊酯等菊酯类药剂间具有比较低的交互 抗性，对后者抗性为3～20倍，对阿维菌素的抗性为575.6倍；对氟虫脲和氟啶脲没有交互抗 性。PB和TPP对阿维菌素分别增效8.2和5.5倍，说明小菜蛾对阿维菌素的抗性可能与多功能 氧化酶（MFO）和羧酸酯酶有关。通过差光谱技术测定了阿维菌素抗性和敏感小菜蛾细胞色 素P450的含量，抗性品系是敏感品系的1.38倍。