Cry1Ba3、Cry1Ia8蛋白对Cry1Ac抗性小菜蛾的杀虫活性研究

利用2种苏云金芽胞杆菌原毒素Cry1Ba3、Cry1Ia8及其组合,分别对Cry1Ac抗性种群小菜蛾幼虫进行生物活性测定。结果表明Cry1Ba3、Cry1Ia8对2种目标试虫均有高毒力,LC50分别为0.2175、0.6706μg/mL;Cry1Ba3毒力3倍于Cry1Ia8。2种蛋白混配的结果也表现出高毒力,LC50为0.4375μg/mL,没有显著的协同增效作用,也不存在拮抗。敏感与抗性小菜蛾种群生测结果统计分析比较,结果表明这2种蛋白及其组合与Cry1Ac并无交互抗性。     

粉纹夜蛾离体细胞对Bt Cry1Ac毒素的抗性发展及其交互抗性

以Cry1Ac活性毒素逐代筛选抗性粉纹夜蛾离体细胞BTI-TN-5B1,抗性发展速度呈S形曲线,经56代选择后,抗性比上升至1 280倍.在去除选择压力后,抗性比逐渐下降.低水平抗性细胞抗性衰退较快,而高水平抗性细胞抗性衰退较缓慢.抗性比衰退至1.5倍的细胞在复筛后抗性比恢复较快.抗性细胞对苏云金杆菌工程菌GC-91(Bt GC-91)、苏云金杆菌鲇泽亚种(B.t.awazai)和苏云金杆菌库斯塔克亚种(B.t.kurstaki)的复合毒素晶体的活性毒素都具有较高的交互抗性,但对农药无交互抗性,对杆状病毒的敏感性也没发生变化.     

新疆MEAM1烟粉虱隐种对吡虫啉的抗性遗传力分析及交互抗性测定

采用Tabashnik的域性状指标分析了新疆MEAM1(Middle-East-Asia-Minor l)烟粉虱隐种对吡虫啉的抗性现实遗传力(h2)和不同致死率下的抗性发展速率,同时测定了抗性种群对不同类型杀虫剂的交互抗性。结果表明,在30%~50%较低的选择压力下,新疆MEAM1烟粉虱隐种连续汰选8代后,对吡虫啉的抗性上升28.01倍,抗性现实遗传力h2为0.429 7。假设田间种群现实遗传力为实验室筛选估算值的1/2,即h2=0.214 9,对新疆MEAM1烟粉虱隐种对吡虫啉的抗性发展速率估算结果表明:在药剂选择压力为50%~60%下,若使其对吡虫啉的抗性增长10倍,则需要生长10~8代;而在药剂选择压力为70%~90%下,若使其抗性增长10倍,则仅需要生长6~4代。表明新疆MEAM1烟粉虱隐种对吡虫啉产生抗性的风险很大。交互抗性测定结果显示:抗性种群对同类型的杀虫剂吡虫清和噻虫嗪分别产生了10.78倍和4.75倍的中等至低水平交互抗性;对多杀菌素、毒死蜱、吡丙醚和高效氯氰菊酯的敏感性有所降低;对阿维菌素、氟啶虫胺腈和乙基多杀菌素等杀虫剂则无交互抗性。     

蛋白质转导结构域增加Cry1Ac对小菜蛾的毒力研究

蛋白质转导结构域是一类能自动穿透细胞膜,并能作为载体将其他生物大分子携带进入细胞膜内的一段富含精氨酸的多肽。本研究通过遗传重组的方法,构建蛋白质转导结构域TAT与Bt杀虫蛋白Cry1Ac的融合基因及其表达载体TAT-Cry1Ac,对表达蛋白的生测结果表明,TAT极为显著地增加Cry1Ac对小菜蛾的杀虫毒力,增效倍数达到5.54倍,预示着TAT在微生物杀虫蛋白领域可能有着良好的应用前景。     

嘉花1号—抗白背飞虱的优良粳稻品种

嘉花1号具有抗白背飞虱的双重抗性机制,即拒食性和杀卵抗性。田间调查结果表明,在不施用任何杀虫剂的情况下,在嘉花1号的全部生育过程中,白背飞虱的种群一直保持较低水平,不至于对水稻构成危害。     

1-取代苯胺基- 4,4-二甲基-2-(1H-1,2,4-三唑-1-基)-1-戊烯-3-酮的合成及其生物活性

为寻找高活性的烯基三唑类杀菌剂,利用1-二甲氨基-4,4-二甲基-2-(1H-1,2,4-三唑-1-基)-1-戊烯-3-酮与取代苯胺进行亲核取代反应,合成了一系列新型1-取代苯胺基-4,4-二甲基-2-(1H-1,2,4-三唑-1-基)-1-戊烯-3-酮化合物,其结构经元素分析、核磁共振氢谱确认。由1H NMR分析结果推测该类化合物E式构型为优势产物。初步生物活性测试结果表明,化合物 1n (取代基R=3-OCH3)在50 μg/mL浓度下对葡萄白腐菌Coniothyrium diplodiella、黄瓜黑星菌Cladosporium cucumerinum等的抑制率均达到100%;在10 μg/mL浓度下对促进黄瓜子叶生根的活性达到155.2%。     

灭线磷降解菌DS-1在土壤中的定殖及对常用杀菌剂的敏感性

测定了3种灭线磷降解菌的降解能力,结果表明,三株能够较好降解灭线磷的细菌DS-1、F2和G2中,DS-1对灭线磷的降解效果最好,采用平板计数法对DS-1田间定殖及灭线磷降解实验的研究表明,土壤接菌14d后DS-1的生长达到最高峰,随后逐渐衰退,加灭线磷的处理DS-1菌数量明显高于其他不加灭线磷的处理,说明DS-1主要利用灭线磷生长;DS-1对灭线磷的降解实验表明,加DS-1菌液的灭菌土中灭线磷的降解率高于同样条件下的非灭菌土中灭线磷的降解率,加菌液的灭线磷的降解率高于不加菌液的灭线磷的降解率,说明灭线磷的降解主要依靠DS-1。田间常用杀菌剂对灭线磷降解菌DS-1的生长及灭线磷降解的影响研究表明,保护性杀菌剂对DS-1的生长以及灭线磷的降解影响较大,内吸性杀菌剂对两者的影响较小。     

Resistance of wheat to septoria tritici blotch (Mycosphaerella graminicola) and associations with plant ideotype and the 1BL−1RS translocation

Septoria tritici blotch (STB) is a major disease of wheat, reaching epidemic proportions in many parts of the world. In several studies, taller, later-maturing cultivars have had lower disease levels. This study was undertaken to investigate the genetic associations of natural field infection by STB with disease-escape mechanisms related to heading date and height components, mainly leaf spacing, in a population where height and maturity are not controlled by major genes. In field trials of a single seed-descent population of a cross between two nonsemi-dwarf cultivars, Apollo (with strong partial resistance to STB) and Thésée (susceptible), conducted over 3 years, there was a negative correlation between STB and heading date. There was no correlation between STB and distance from stem base to leaf 2; and there was an unexpected positive correlation between STB and distance from flag leaf to leaf 2, which contradicted the so-called 'ladder effect' postulated in STB epidemiology. No effect was detected of the presence of the 1BL−1RS translocation on STB levels. The largest single contributor to variation in STB levels was genetic variation between the progeny lines, and the narrow-sense heritability was 42%. These results suggest that breeders can select for STB resistance alongside optimal stature within the range of height which is adaptive in a particular environment.     

中巴地球资源一号卫星在金塔绿洲荒漠化监测中的应用研究

遥感技术的发展和应用为荒漠化土地监测和生态工程建设提供了先进的调研和监控手段 ,可在西部大开发和生态环境建设中发挥巨大作用。本文应用美国 Landsat- 5 TM影像 (1 987年 )和资源一号卫星 CCD影像 (2 0 0 0年 )进行对比分析 ,揭示出金塔绿洲荒漠动态发展趋势 ,肯定了金塔绿洲林业生态建设成就。表明资源一号卫星完全可以成功地应用于中国西部地区的荒漠化监测和林业生态建设工程     

苏云金芽孢杆菌Cry1Ie1蛋白末端缺失的研究

通过PCR扩增法 ,以cry1Ie1全长基因为模板 ,分别得到不同末端缺失的基因片段 ,转化大肠杆菌BL21(DE3)中诱导表达 ,得到 6种末端缺失蛋白。对小菜蛾生物测定结果表明 ,缺失蛋白IE659、IE656分别缺失了C末端60个和63个氨基酸残基 ,对小菜蛾的杀虫活性与Cry1Ie1全长蛋白相当 ;IE648、IE045分别缺失了C末端 71个氨基酸残基和N末端缺失44个、C末端缺失63个氨基酸残基 ,对小菜蛾的活性提高了50% ;IE633、IE105分别缺失了C末端 86个氨基酸残基和N末端缺失 104个、C末端63个氨基酸残基 ,丧失了对小菜蛾的活性。试验明确Cry1Ie1蛋白的最小活性区N端在45～104氨基酸位点之间 ,C端在633～648氨基酸位点之间。     

RF－1小麦品系抗赤霉病机理初探

高抗赤霉病且丰产性较好的ＲＦ－１小麦品系和泗麦２号小麦比较后发现：该品种在扬花后残留的花药极少，穗形结构松散，麦穗主轴弯曲度大，穗轴表皮下机械组织排列紧密且层次多。室内离体麦穗接种的病情扩展较对照品种慢。     

对氯苯丙酮肟衍生物的合成及其生物活性

为寻找新型结构的农药先导化合物,采用1-对氯苯基-3-氯-1-丙酮为原料,合成了14个结构新颖的对氯苯丙酮肟衍生物,其化学结构经1H核磁共振和元素分析确证。初步的生物活性试验结果表明,该类化合物具有一定的杀虫和除草活性,其中化合物 Ⅴi、Ⅴe和Ⅴh 在 50 mg/L浓度下对淡色库蚊Culex pipiens pallens的致死率达到100%。     

棉花GhRAR1基因调控棉花抗黄萎病机理的研究

棉花黄萎病是一种严重影响棉株生长的土传维管束真菌病害。挖掘抗性基因,解析抗病机制,对创制棉花抗病种质防御棉花黄萎病具有重要意义。本研究从抗病棉花品种‘中植棉2号’中获得GhRAR1基因,采用病毒诱导的基因沉默(VIGS)技术、基因过表达及qRT-PCR技术探究GhRAR1介导的棉花抗黄萎病机制。结果表明,GhRAR1的表达受棉花黄萎病菌诱导。GhRAR1沉默棉株对黄萎病菌敏感性增强,表现为植株病情指数升高、叶片萎蔫、茎部维管束组织褐变加重。GhRAR1沉默棉株中活性氧(ROS)生成基因GhRbohD表达量低,H₂O₂积累量少。过表达GhRAR1基因的拟南芥植株对棉花黄萎病抗性增强,AtRbohD表达量高,H₂O₂积累量多,发生过敏反应(HR),菌丝扩散被抑制。推测GhRAR1可能调控ROS积累和HR,从而介导棉花对黄萎病菌的抗性。     

粉纹夜蛾离体细胞对Bt Cry1Ac毒素的抗性发展及其交互抗性

以CrylAc活性毒素逐代筛选抗性粉纹夜蛾离体细胞BTI-TN-5B1抗性发展速度呈S形曲线，经56代选择后，抗性比上升至1280倍。在去除选择压力后，抗性比逐渐下降。低水平抗性细胞抗性衰退较快，而高水平抗性细胞抗性衰退较缓慢。抗性比衰退至1．5倍的细胞在复筛后抗性比恢复较快。抗性细胞对苏云金杆菌工程菌GC-91(BtGC-91)、苏云金杆菌鲇泽亚种(B.t.atoazai)和苏云金杆菌库斯塔克亚种(B．t．kurstaki)的复合毒素晶体的活性毒素都具有较高的交互抗性，但对农药无交互抗性，对杆状病毒的敏感性也没发生变化。     

SGT1 contributes to maintaining protein levels of MEK2DD to facilitate hypersensitive response-like cell death in Nicotiana benthamiana

Gene silencing revealed that the mitogen-activated protein kinase (MAPK) cascade in Solanaceae consisted with MEK2-WIPK/SIPK, is required for R protein-induced hypersensitive response (HR) cell death and/or resistance. Overexpression of MEK2^DD results in HR-like cell death. MEK2^DD is a phospho-mimic and constitutive active form harboring mutations at putative phosphorylation sites of upstream MAPKKK. The molecular mechanism that induces HR-like cell death is unknown. Here we report SGT1 is required for the accumulation of MEK2^DD protein, not MEK2^WT. Virus-induced gene silencing of SGT1 resulted in low protein accumulation of MEK2^DD. This result suggests that SGT1 has a positive role in the accumulation of the MEK2 active form protein to facilitate signal transduction.     

新化合物HIA-1的除草活性评价

为明确新化合物O,O-二甲基-1-(2,4-二氯苯氧基乙酰氧基)呋喃甲基膦酸酯(HIA-1)的开发应用前景, 对其除草活性、杀草谱、对作物的安全性、施药适期、吸收部位进行了综合评价。温室盆栽试验结果表明:该化合物在有效成分用量为600 g/hm2剂量下对苘麻、反枝苋、马齿苋等常见阔叶杂草具有较高的除草活性,茎叶处理后防效在90%以上;在有效成分用量为1 600 g/hm2剂量下对小麦、玉米较安全,鲜重抑制率分别为9.06%和12.04%,对棉花、花生、大豆和油菜有明显的药害;使用适期为杂草2~3叶期。活性炭隔离和植株茎叶喷雾、灌根试验结果表明,该化合物可通过胚芽、胚根、根、茎、叶吸收进入植物体内。化合物HIA-1具有作为小麦和玉米田阔叶杂草防除药剂进一步开发应用的价值。     

Cry1Ah蛋白对多异瓢虫和日本通草蛉的安全性评价

非靶标生物在转基因抗虫作物的环境安全性评价中具有非常重要的地位。本研究系统评估了新型Bt杀虫蛋白Cry1Ah对多异瓢虫幼虫、成虫和日本通草蛉成虫各项生物学指标的影响。结果表明,取食体表布满Cry1Ah蛋白的桃蚜后,多异瓢虫幼虫存活率、幼虫历期、蛹历期、体质量、雌雄成虫寿命、雌虫产卵量与对照相比均差异不显著。日本通草蛉成虫取食含有Cry1Ah蛋白的蜂蜜水后,雌雄成虫寿命、雌虫产卵量与对照间均差异不显著。因此,Cry1Ah蛋白对多异瓢虫和日本通草蛉的各项生命指标无显著的不利影响,这为转Cry1Ah基因抗虫棉花商业化释放前的安全性评价提供重要的技术支撑。     

SrfC of Pseudomonas cichorii JBC1 affects its attachment to the host surface and host tissue infection

Plant pathogenic Pseudomonas species produce effectors, toxins and cyclic lipopeptides to infect various host plants. Despite many studies aiming to understand the underlying mechanisms of virulence in Pseudomonas spp., the function of genes in the srf gene cluster including srfC, which was formerly known as HopL1, remains undetermined. To investigate the roles of srf genes in the virulence of the bacterial pathogen, each srfA, srfB, srfC and srfD gene from the srf cluster of Pseudomonas cichorii JBC1 was knocked out. When tomato seedlings were infected with the knockout mutants by flood inoculation, disease incidence was suppressed only in srfC-defective mutants (∆srfC) compared to wildtype. Interestingly, when the ∆srfC strain was inoculated directly into the apoplast of tomato leaves by vacuum infiltration, disease developed similar to that of the wildtype. In addition, the ∆srfC strain showed defective swarming motility and biofilm formation, and the attachment of ∆srfC cells on the leaf surface was significantly reduced compared to wildtype. Furthermore, droplets of the ∆srfC culture supernatant did not spread on a hydrophobic surface, unlike the wildtype. The results indicate that the SrfC protein plays important roles in swarming motility, biofilm formation and attachment/colonization on host surfaces; thus, it is beneficial for the pathogen's dispersion and entry into host tissues and consequently contributes to disease development. This study elucidates for the first time the functional role of srfC in P. cichorii virulence. The results will broaden understanding of plant and bacterial pathogen interactions.