The effect of plant surface characteristics on resistance of rice to the brown planthopper, Nilaparvata lugens

Increased activity of the brown planthopper, Nilaparvata lugens (Stål) on rice variety IR46 over that observed on varieties IR22 and IR62 was shown to be due to the chemical composition of the surface wax. Reduced settling and probing of the plant surface after exploration, and a tendency to move off the stem onto the leaves as a result of chemical cues from the wax make this a potentially important resistance mechanism in rice. Bioassays have shown that the effect is caused by the hydrocarbon- and carbonyl-containing fractions of the wax of IR46. An investigation of N. lugens behaviour on initial contact with the surface of several other varieties of rice has indicated a similar effect for IR36, and a much stronger effect with the wild rice WR221.

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Résumé La composition de la cire superficielle s'est révélée la cause de l'accroissement de l'activité de N. lugens sur la variété de rix IR46, par rapport aux variétés IR22 et IR62. Un mécanisme important de la résistance potentielle du riz est dû aux conséquences des caractéristiques chimiques de la cire: établissement et sondage de la plante réduits après exploration, et tendance à quitter la tige pour gagner les feuilles. Des expériences ont montré que ces effets étaient provoqués par les fractions de la cire de IR46 contenant des hydrocarbures et des carbonyls. L'étude du comportement de N. lugens, lors du premier contact avec la surface de plusieurs autres variétés, a montré un effet semblable pour IR36 et un effet beaucoup plus fort avec le riz sauvage WR221.

     

Potential resistance of tricin in rice against brown planthopper Nilaparvata lugens (Stål)

The aerial parts of resistant rice plant (IR36) was immersed in 85% ethanol at room temperature, and ethanol-soluble extracts were prepared. Different solvents including petroleum ether, ethyl acetate, absolute ethanol, and water were then used to separate the ethanol-soluble extracts and different solvent fractions were obtained. These fractions were tested for their effects on the mortality rate of the brown planthopper nymphae (BPH). The results indicated that EtOAc fractions had significant effects on the mortality of brown planthopper nymphae after the third day of treatment. EtOAc fractions of resistant rice plants (IR36) were separated using column chromatography over silica gel and 5,7,4′ -trihydroxy-3′,5′-dimethoxyflavone (tricin) was isolated. After the BPH were allowed to feed on diets containing tricin for 15 days, it was found that the weight of honeydew of the nymphae showed a decrease as tricin concentrations in the diets increased. The mortality rate of the nymphae increased with increasing tricin concentration. The corrected mortality rate was 58.21% for the 3rd instar nymphae and 31.75% for the 4th instar nymphae, respectively, at 500 μg/ml concentration. In addition, tricin (500 μg/ml) significantly inhibited oviposition behavior and feeding of the brown planthopper females in choice tests when spread on susceptible rice plant (TN1).     

Teleconnection between the early immigration of brown planthopper (Nilaparvata lugens Stål) and ENSO indices: implication for its medium- and long-term forecast

Teleconnection between the early immigration of brown planthopper (BPH) and El Nino/Southern Oscillation (ENSO) indices from January of two years previously to the current June was investigated to make long-term forecast. The teleconnection results were as follows: ENSO indices which were significantly correlated with the early immigration of BPH were primarily sea surface temperature anomalies (SSTA) in N3, N4 and N3.4 regions, accounting for 71.8% of the total. Significant ENSO indices from two years and one year before the immigration events had a proportion of about 84%, while those in the current year only accounted for 16.7%. There was significantly negative correlation between the early immigration of BPH and SSTA in each Nino region from two years before to the previous spring, whereas there was significantly positive correlation between these two factors during the period from the previous winter to the current spring. The significant correlation between the early immigration of BPH and SSTA in each Nino region in the last summer and autumn did not show any obvious tendencies. The relationship between the southern oscillation index (SOI) and the early immigration of BPH was opposite to that between the immigration and SSTA in each Nino region. The above mentioned significant ENSO indices were used as key factors to build forecasting models for the early immigration of BPH by step-wise multiple linear regression analysis. Finally, 12 integrated forecasting models were obtained, which could make predictions 3–27 months ahead and had a predictive accuracy of 88.9%.     

温度对褐飞虱发育、存活和产卵影响的关系模型

设置系列恒温19、22、25、28、31、34℃,测定了温度对褐飞虱发育、存活和产卵的影响,建立了温度对褐飞虱生物学参数影响的关系模型。试验结果表明:(1)褐飞虱卵和若虫的发育历期在28℃下最短。除22℃以外,短翅型雌若虫的发育历期长于雄若虫的发育历期。(2)34℃下,褐飞虱卵未成功孵化,推测34℃是褐飞虱发育的限制性高温。不同温度下若虫的存活率为:25℃22℃28℃19℃31℃;低温主要导致低龄若虫死亡,而高温则主要导致高龄若虫死亡。(3)不同温度下产卵前期为19℃31℃22℃25℃28℃。产卵期22℃时最长。短翅型雌虫寿命随着温度降低而延长,产卵量在28℃时最大(256粒),19℃时最低(108粒)。(4)采用温度(x)与褐飞虱各生物学参数(y)间进行回归分析,获得一系列关系模型;其中,卵历期(y=0.079 x2-4.462 x+70.536),若虫历期(y=0.233 x2-12.886 x+189.878),产卵前期(y=0.068 x2-3.614 x+49.88)和短翅型雌成虫寿命(y=-0.622 x+35.03)与温度间具有显著的回归关系。     

褐飞虱种群生命系统管理模型的研究

本文引用太湖稻区单季晚稻褐飞虱种群动态和为害损失研究的结果,以车厢法(boxcar train)原理为基本框架,建立褐飞虱种群动态模拟模型,并结合Bellman的动态规划最优化原理组建褐飞虱种群生命系统管理模型。经川沙县1984—1989年预测圃资料验证,模型模拟值与田间实查值相当吻合,累积虫量误差在1.4％—16.3％之间,平均11.4％;种群管理的模型决策与实际经验决策的准则不同,造成两种决策结果的差异。     

Proteolytic processing of Bacillus thuringiensis toxin Cry1Ab in rice brown planthopper, Nilaparvata lugens (Stål)

To understand the low toxicity of Cry toxins in planthoppers, proteolytic activation of Cry1Ab in Nilaparvata lugens was studied. The proteolytic processing of Cry1Ab protoxin by N. lugens midgut proteases was similar to that by trypsin activated Cry1Ab. The Cry1Ab processed with N. lugens midgut proteases was highly insecticidal against Plutella xylostella. However, Cry1Ab activated either by trypsin or the gut proteases of the brown planthopper showed low toxicity in N. lugens. Binding analysis showed that activated Cry1Ab bound to brush border membrane vesicles (BBMV) from N. lugens at a significantly lower level than to BBMV from P. xylostella.     

盘拍法调查褐飞虱种群的准确性测定

用盘拍法调查褐飞虱虫量的查获率仅在30％～70％之间,查获率的高低因虫口密度、水稻生育期及盘面涂抹粘胶与否而异。在所拟会的24个查获率回归方程中,极大部分的拟会效果是比较好的。当盘拍虫量在水试验范围以内时,代入相应的方程内,即能求出查获率,换算出实有虫数。     

The multicopper oxidase gene family in the brown planthopper,Nilaparvata lugens

The multicopper oxidase (MCO) family of enzymes includes laccases, ascorbate oxidases, bilirubin oxidases and a subgroup of metal oxidases. On the basis of a bioinformatics investigation, we identified 7 genes encoding putative multicopper oxidase proteins in the genome of the brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae). MCO1 and MCO2 are conserved, while others diverse in insects. Analysis of developmental and tissue-specific expression patterns revealed the following: NlMCO2 was mainly expressed in the integument, and its expression peaked periodically during molting; NlMCO3 was an ovary-specific MCO gene with a high expression level only at the adult stage; NlMCO4 was a salivary gland-specific MCO gene that was expressed at all developmental stages; NlMCO5 only had short-term expression in the middle of the fourth instar stage and was expressed mainly in the gut; NlMCO6 had a developmental expression pattern similar to that of NlMCO2 and was expressed in most N. lugens tissues; and NlMCO1 was expressed in most N. lugens tissues except for the testis, whereas NlMCO7 was mainly expressed in the gut and the Malpighian tube. BPHs injected with double-stranded RNA (dsRNA) targeting NlMCO2 failed to pigment and sclerotize, were colorless and soft-bodied and subsequently died in a short time. Lethal phenotypes were also observed in insects challenged by dsRNA targeting NlMCO6. However, no observable morphological or internal structural abnormality was obtained in the insects treated with dsRNA for NlMCO1, NlMCO3, NlMCO4, NlMCO5 or NlMCO7.     

应用马尔可夫链理论对褐飞虱和白背飞虱发生程度的预测

褐飞虱Nilaparvata lugens (Stál)和白背飞虱Sogatella furcifera (Horváth) 是我国稻区的主要迁飞性害虫,给水稻生产带来严重危害.以重庆市秀山县1983～2007年田间褐飞虱和白背飞虱发生程度的时间序列资料,运用基于马尔可夫链理论的转移概率预测法,构建了1～5阶转移概率矩阵,根据每一阶概率矩阵单独进行回报的历史符合率计算各阶转移概率矩阵的权重,以预报年前5a褐飞虱和白背飞虱的连续发生状态预测第6年的发生级别.回报20a的结果历史符合率均达到90%,对2008年的预测也符合当年田间实际发生情况.该方法构建的5阶转移概率矩阵及其权重对于秀山县及其邻近地区褐飞虱和白背飞虱发生程度的长期预报具有重要指导意义,为害虫的长期可预测性提供了一种快速、有效的方法.     

Tagging the brown planthopper,Nilaparvata lugens,with the stable isotope nitrogen-15; method for labelling and detection

The brown planthopper (BPH), Nilaparvata lugens (***Stål), is a serious pest of rice in tropical Asia (IRRI, 1979).     

水稻品种中抗褐飞虱抗原次生物质的分析

借助高效液相色谱(HPLC)技术,研究了130份对褐飞虱生物型Ⅱ具有不同抗性水平的水稻样品(26个品种)中13个次生物质含量(峰面积)的差异;运用主成分分析和多元回归分析,建立了水稻品种抗性级别的预测模型:Y=3.4593-0.02491X₁+0.08475X₂-0.04227X₈+0.1174X₁₂.结果表明,水稻的抗性水平与峰面积值之间极显著相关(r²=0.84,P<0.01),峰1、峰2、峰8、峰12对应的次生化合物是影响水稻对褐飞虱生物型Ⅱ抗性水平的主要抗原次生化合物;水稻品种中起抗虫作用的抗原次生物质不止一种,而是几种的组合,而且它们对水稻抗虫性的贡献权重是不完全相同的.     

中国与越南褐飞虱和白背飞虱生物型研究

【目的】监测我国与越南褐飞虱Nilaparvata lugens St?l和白背飞虱Sogatella furcifera Horvath生物型,为抗虫育种工作提供指导。【方法】应用群体集团检测法和蜜露量检测法研究了中国广西、云南、河南、湖南、重庆、贵州和越南河内、河静、顺化、胡志明市和九龙江田间褐飞虱和白背飞虱的致害特性和生物型组成结构。【结果】我国主要稻区(除云南思茅外)和越南中北部的田间褐飞虱以Ⅱ型的比例多,对含Bph1、bph2基因的鉴别品种表现为致害;云南思茅的田间褐飞虱以Ⅱ+Ⅱ型的比例多,对含Bph1、bph2和bph4基因的鉴别品种表现为致害或强致害;越南胡志明市、九龙江的田间褐飞虱以Ⅱ+Ⅱ型的比例多,对含Bph1、bph2、Bph3、bph4基因的鉴别品种主要表现为致害或强致害。我国白背飞虱以Ⅰ型比例较多;越南顺化和河内以Ⅱ型比例多;所有监测点白背飞虱的致害特性总体表现为对含Wph1、Wbph2基因的鉴别品种的致害能力较强,对Wbph3的致害能力表现不一,对含Wph5基因的鉴别品种表现为中等致害。【结论】抗虫育种选择抗源时,不要选含Bph1、bph2基因的水稻品种作为褐飞虱抗源,不要选含基因Wbph1或Wbph2的水稻品种作为白背飞虱抗源。     

褐飞虱为害对不同抗性水稻品种苗期根系几种营养物质和总酚含量的影响

本文以对褐飞虱Nilaparvata lugens(St?l)具不同抗性水平的水稻品种为研究对象,通过在苗期接入不同密度褐飞虱后测定水稻根系可溶性糖、游离氨基酸、可溶性蛋白质和总酚变化情况,以明确水稻抗虫性与根系生理生化物质含量的关系.研究结果表明,根系中的可溶性糖除了苗龄8d不接虫的处理,其余处理均以感虫品种TN1含...     

Cloning and characterization of two genes coding for the histone acetyltransferases,Elp3 and Mof,in brown planthopper (BPH), Nilaparvata lugens (Stål)

Histone acetylation is a vital mechanism for the post-translational modifications of chromatin components. Histone acetyltransferases (HATs) are critical elements that determine histone acetylation and regulate chromatin dynamics and gene expression. While histone acetyltransferases have been well studied in mammals and Drosophila melanogaster, information from agriculturally important insect pests is still limited. In our effort to understand the epigenetic mechanisms regulating development in the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Geometroidea), a major rice pest in many parts of Asia, two full-length cDNA sequences encoding HAT members of the GNAT and MYST family, namely NlElp3 and NlMof, respectively, were isolated and structurally and phylogenetically characterized. The NlElp3 contains an open reading frame (ORF) of 1656 bp encoding a protein of 551 amino acids. The NlMof contains a 1353 bp ORF encoding a protein of 450 amino acids. Sequence analysis showed that NlElp3 contains GNAT-type HAT domain and Radical SAM domain, and NlMof contains chromodomain and MOZ-SAS acetyltransferase domain. Multiple sequence alignments showed that NlElp3 and NlMof have high amino acid sequence identity with other insect homologues. Expression analysis of the NlElp3 and NlMof revealed significant differences in mRNA expression levels among N. lugens developmental stages, suggesting that HAT activities of NlElp3 and NlMof may be controlled, at least in part, by their developmental regulation. Remarkably, the mRNA expression levels of NlElp3 and NlMof in female adults were significantly higher than that in male adults, supporting an important role for both genes in female reproductive function in N. lugens.     

亚洲稻区灰飞虱抗药性研究进展

灰飞虱Laodelphax striatellus(Fallen)是亚洲稻区的一种重要传毒昆虫。20世纪60年代以来,灰飞虱先后对有机氯、有机磷以及氨基甲酸酯类杀虫剂产生了不同程度的抗药性,其抗性机理主要涉及解毒代谢增强和靶标敏感性下降。随着吡虫啉等新型药剂使用面积的扩大,加强抗性监测,制定科学合理的抗性治理策略势在必行。     

Effects of nitrogen on the tolerance of brown planthopper, Nilaparvata Lugens, to adverse environmental factors

The effect of nitrogen content in rice plants on the tolerance of brown planthopper (BPH), Nilaparvata lugens Stal to high temperature, starvation and insecticide, was studied in the laboratory at International Rice Research Institute (IRRI), Philippines. Survival of nymphs and adults, fecundity and egg hatchability were significantly increased by the increase of nitrogen content in host plants at 38℃. Moreover, the survival of nymphs,fecundity and egg hatchability were significantly higher in BPH populations on rice plants with a high nitrogen regimen than those on rice plants with a low nitrogen regimen.Meanwhile, the tolerance of female adults to starvation and nymphs to growth regulator buprofezin on rice plants with a high nitrogen regimen were slightly increased. This indicates that the tolerances of BPH to adverse environmental stresses were positively increased by the application of nitrogenous fertilizer. The outbreak potential of BPH induced by the excessive application of fertilizer in rice fields was also discussed.