Conditional expression of harpinPsscauses yeast cell death that shares features of cell death pathway with harpinPss-mediated plant hypersensitive response (HR)

Conditional expression of harpin_Psscauses yeast cell death that shares features of cell death pathway with harpin_Pss-mediated plant hypersensitive response (HR).Pseudomonas syringae pv.syringae 61 hrp Z gene encodes harpin_Pss, a 34.7 kD extracellular protein that elicits a hypersensitive response (HR) in plants. Conditional expression of either full-length or truncated hrp Z sequences under the GAL1 promoter caused cell death in Saccharomyces cerevisiae Y187. Plating of pYEUT- hrp Z transformants on a medium containing galactose resulted in complete inhibition of colony formation, whereas their growth on a glucose-based medium was unaffected. Western blot analysis confirmed the expression of harpin_Pssin yeast cells transformed with pYEUT- hrp Z and grown in galactose-containing medium. A time-dependent decline in the percentage of trypan blue-excluding cells in cultures of pYEUT- hrp Z transformants was observed when cultured on galactose-containing medium. Similarly, the number of viable cells reduced to about 50% within 6 h. There were similarities in the harpin_Pss-mediated cell death in plants and yeast cell death (YCD). Galactose-induced cell death in pYEUT-hrp Z transformants of S. cerevisiae Y187 was suppressed by a protein kinase inhibitor K252a (10 μ M). The viability of pYEUT- hrp Z transformants was prolonged in the presence of 100 U ml⁻¹catalase suggesting a role for the oxidative burst in YCD that was further supported by the flow cytometric patterns of propidium iodide uptake by yeast cells. Overall, it appears that yeast provides a useful model system to understand the molecular mechanism of harpin_Pss-mediated cell death.     

Contact and fumigant activities of constituents of Foeniculum vulgare fruit against three coleopteran stored‐product insects

The insecticidal activities of materials derived from the fruit of fennel, Foeniculum vulgare, against adults of Sitophilus oryzae, Callosobruchus chinensis and Lasioderma serricorne were examined using direct contact application and fumigation methods. The biologically active constituents of the Foeniculum fruits were characterized as the phenylpropenes (E)‐anethole and estragole, and the monoterpene (+)‐fenchone, by spectroscopic analysis. Responses varied with insect species, compound, dose and exposure time. In a filter paper diffusion test, estragole at 0.168 mg cm^?2 caused 91% mortality to S oryzae adults within 1 day after treatment (DAT), whereas (+)‐fenchone and (E)‐anethole gave over 90% mortality at 2 and 4 DAT, respectively. Against C chinensis adults, all test compounds revealed potent insecticidal activities at 0.021 mg cm^?2 at 2 DAT. Against L serricorne adults at 0.105 mg cm^?2, (E)‐anethole gave 100% mortality at 1 DAT, whereas 90 and 60% mortality at 4 DAT was achieved with estragole and (+)‐fenchone, respectively. In a fumigation test, the test compounds were much more effective against adults of S oryzae, C chinensis and L serricorne in closed cups than in open ones, indicating that the insecticidal activity of test compounds was largely attributable to fumigant action. As naturally occurring insect‐control agents, the F vulgare fruit‐derived materials described could be useful for managing field populations of S oryzae, C chinensis and L serricorne. © 2001 Society of Chemical Industry     

一硫代磷酸酯类杀虫剂的微生物降解

在纯培养条件下测定了分离株 YF0 5对对硫磷等一硫代磷酸酯类杀虫剂的降解作用。在接种量 (OD4 15nm)为 0.2、pH7.0、30℃条件下 ,测得 10、25、50、100、200、500 mg/L对硫磷的降解符合一级动力学特征 ,其降解速率常数分别为 0.077、0.123、0.128、0.119、0.084、0 .013,高浓度对硫磷对 YF05菌有抑制作用 ;分离株 YF05在不同温度及 pH下对对硫磷的降解作用为 40℃ >30℃ >20℃ ,pH8.0 >pH7.0 >pH6 .0。同样条件下 ,YF05对杀螟硫磷和甲基对硫磷也有较好的降解作用 ,对甲基对硫磷的降解速率常数与对硫磷相仿 ,对杀螟硫磷的降解速率常数略高于对硫磷。     

4种棉蚜抗药性种群的生命力及繁殖力

用4种杀虫剂以浸渍法分别累代处理敏感棉蚜,以选育抗药性。每选育4代进行1次毒力测定及生命力和繁殖力的观察。选育至12代,棉蚜对溴氰菊酯的抗性倍数达4031.4倍,对久效磷、灭多威及硫丹的抗性倍数分别仅为6.3、6.1及4.0倍。棉蚜对溴氰菊酯抗性水平较低时,其生命力及繁殖力略低于敏感品系,随着抗性水平的提高,其生命力和繁殖力也随之增强,RF_(8)接近敏感品系的水平,RF_(12)及RF_(16)则明显超过。灭多威及硫丹抗性种群随抗性水平的提高,其生命力及繁殖力表现不同程度的降低。久效磷抗性种群,各抗性水平下其生命力和繁殖力与敏感品系相比无显著差异。     

从配合力分析探讨甘蔗家系抗黑穗病的育种潜力

采用5×4不完全双列杂交设计选配的第1次无性种茎为试验材料,在人工浸渍接种黑穗病菌条件下,估算了9个亲本及其组合在新植蔗和宿根蔗的配合力效应。结果表明:①20个家系抗性差异较大,以CP67/412、ROCl为母本的半同胞家系表现较强抗病性,而以CP72/1210、CP65/357为母本的半同胞家系表现一定感病性;②甘蔗抗黑穗病遗传是由加性效应基因和非加性效应基因共同控制;③发现CP67/412、ROClgca效应值较高,CP57/614次之,均具有可作为抗源亲本的育种潜力,④根据配合力总效应值评价组合,认为CP67/412×崖84/153、ROCl×崖71/374、CP67/412×崖71/374、ROCl×崖84/153、CP67/412×崖73/512、CP57/614×崖84/153是抗黑穗病较强的组合,可用于今后抗黑穗病育种计划。     

苏北地区小麦黄矮病发生初报

 自80年代以来,苏北地区徐州、淮阴、盐城、南通、扬州等市小麦生长中后期出现的黄枯叶现象相当普遍,90年后发生更趋严重。1992、1994年有些市(县)较大面积发生。     

普通野生稻种质资源对纹枯病的抗性鉴定

 1987-1990年我们与本院水稻所野生稻研究组协作,对该组提供的2021份普通野生稻资源进行抗纹枯病鉴定,把人工繁殖的纹枯病菌接种于稻茎基部,经年度重复鉴定,取得如下结果。     

樱桃致死黄化病病原研究

 在电镜下,樱桃致死黄化病株筛管细胞中,观察到典型的类菌原体,大多数为球状,大小为132-321×168-520nm,无细胞壁,仅有双层细胞膜。抗菌素试验表明,四环素对本病具一定的治疗效果;而青霉素无效。初步认为此病为类菌原体引起的病害。     

生草园捕食性天敌东亚小花蝽的人工操纵技术

在北京巨山农场果园中，分别在６月初和６月中旬，刈割苹果树行间的紫花苜蓿并将其放在树冠下后，东亚小花蝽既向割草区周围的紫花苜蓿上扩散，也向割草区苹果树上迁移。割草后３天，割草区周围紫花苜蓿上小花蝽数量增加２０％～１１９％，其增加量随距割草区距离的增加而减少，割草区苹果树冠上小花蝽数量比割草前增加２～３倍，蝽螨比可提高１４倍，树冠小花蝽增加的数量受小花蝽扩散能力和割草时间的影响。试验结果表明，适时刈割苹果园中的紫花苜蓿，对控制害螨有明显的作用     

14种农药的非致死浓度对拟长毛钝绥螨繁殖和定居的影响

在室内测试了１４种农药对拟长钝缓螨的非致死浓度及其对定居和繁殖的影响。氯氰菊酯，粉锈宁，克螨特，三氯杀螨醇对拟长毛钝绥螨的繁殖，叶上定居及着卵量都有很大的影响。氧化乐果影响拟长毛钝绥螨的繁殖，对定居影响不大。天王星，高效灭百可，灭扫利，功夫不影响，镇量影响在植侏上定居和叶上着卵量。双甲脒，卡死克，阿波罗对拟长毛钝绥螨影响不显著。爱力螨克和尼索朗对拟长毛钝缓螨的繁殖，定居，着卵量均不良的影响。