褐飞虱致害性变异机制研究进展

褐飞虱Nilaparvata lugens Stal是危害水稻Oryza sativa L.的毁灭性害虫。种植抗虫水稻品种可以控制褐飞虱危害,技术手段绿色、经济且可持续。但是,褐飞虱致害性变异速度快且程度高,常导致抗虫水稻品种使用年限缩短。目前,针对褐飞虱致害性个体表型及分子标记、产生原因与机制、功能基因研究等已开展了大量研究。本文围绕褐飞虱致害性变异产生的遗传基础、分子标记、变异的主动机制和被动机制等方面进行综述,并对该领域未来方向进行展望。为更好地利用抗虫品种控制虫害,做好害虫的致害性监测及制定防治策略提供参考。     

Putative fasciclin-like arabinogalactan-proteins (FLA) in wheat (Triticum aestivum) and rice (Oryza sativa): identification and bioinformatic analyses

Putative plant adhesion molecules include arabinogalactan-proteins having fasciclin-like domains. In animal, fasciclin proteins participate in cell adhesion and communication. However, the molecular basis of interactions in plants is still unknown and none of these domains have been characterized in cereals. This work reports the characterization of 34 wheat (Triticum aestivum) and 24 rice (Oryza sativa) Fasciclin-Like Arabinogalactan-proteins (FLAs). Bioinformatics analyses show that cereal FLAs share structural characteristics with known Arabidopsis FLAs including arabinogalactan-protein and fasciclin conserved domains. At least 70% of the wheat and rice FLAs are predicted to be glycosylphosphatidylinositol-anchored to the plasma membranes. Expression analyses determined from the relative abundance of ESTs in the publicly available wheat EST databases and from RNA gel blots indicate that most of these genes are weakly expressed and found mainly in seeds and roots. Furthermore, most wheat genes were down regulated by abiotic stresses except for TaFLA9 and 12 where cold treatment induces their expression in roots. Plant fasciclin-like domains were predicted to have 3-D homology with FAS1 domain of the fasciclin I insect neural cell adhesion molecule with an estimated precision above 70%. The structural analysis shows that negatively charged amino acids are concentrated along the β1-α3-α4-β2 edges, while the positively charged amino acids are concentrated on the back side of the folds. This highly charged surface distribution could provide a way of mediating protein–protein interactions via electrostatic forces similar to many other adhesion molecules. The identification of wheat FLAs will facilitate studying their function in plant growth and development and their role in stress response.Nucleotide sequence data reported are available in the DBJ/EMBL/GenBank databases under the accession numbers: TaFLA1, DQ872374; TaFLA2, DQ872375; TaFLA3, DQ872376; TaFLA4, DQ872377; TaFLA5, DQ872378; TaFLA6, DQ872379; TaFLA7, DQ872380; TaFLA8, DQ872381; TaFLA9, DQ872382; TaFLA10, DQ872383; TaFLA11, DQ872384; TaFLA12, DQ872385; TaFLA13, DQ872386; TaFLA14, DQ872387; TaFLA15, DQ872388; TaFLA16, DQ872389; TaFLA17, DQ872390; TaFLA18, DQ872391; TaFLA19, DQ872392; TaFLA20, DQ872393; TaFLA21, DQ872394; TaFLA22, DQ872395; TaFLA23, DQ872396; TaFLA24, DQ872397; TaFLA25, DQ872398; TaFL26, DQ872399; TaFLA27, DQ872400; TaFLA28, DQ872401; TaFLA29, DQ872402; TaFLA30, DQ872403; TaFLA31, DQ872404; TaAGP1, DQ872405; TaFLA33, DQ872406; TaFLA34, DQ872407. If requested the database will withhold release of data until publication.An erratum to this article can be found at     

Life table of Xylocoris afer (Hemiptera: Anthocoridae) feeding on eggs of Corcyra cephalonica (Lepidoptera: Pyralidae) and Plutella xylostella (Lepidoptera: Plutellidae)

The aim was to evaluate the biological aspects of Xylocoris afer fed on Corcyra cephalonica and Plutella xylostella eggs. The experiment was conducted with X. afer nymphs aged 12–24?h, one per Petri dish, resulting in a total of 60 nymphs (60 repetitions). On each dish, we placed P. xylostella and C. cephalonica eggs daily, together with a cotton roll moistened with distilled water and conducted daily evaluations. We evaluated the duration, viability, and consumption of nymphal stages, the longevity of males and females, the number of eggs per female, and egg fertility. In addition, the biological data were used to determine the parameters of the fertility life table. The consumption by adults (male and female) of X. afer differed between the preys, the highest consumption was C. cephalonica eggs. Females that consumed eggs of C. cephalonica produced about 90% more eggs and more offspring than those that fed on P. xylostella eggs. Based on our results, it can be inferred that the predator completed its development feeding both on natural prey and the alternative, evidencing the possible potential of X. afer to be used in the biological control of P. xylostella as well as the use of C. cephalonica in mass rearing of this predator under laboratory conditions, aiming its use in applied biological control. However, before being accepted for biological control agent against agricultural pests, various factors should be examined in ecosystem level, as the behavior of predator in different densities of prey.     

Descriptive models for the system of the natural spread of infection of rice dwarf virus (RDV) by the green rice leafhopper,Nephotettix cincticeps Uhler (Hemiptera: Deltocephalidae)

Seasonal changes in the densities of eggs and of 1st instar nymphs of N. cincticeps, a vector of the rice dwarf virus (RDV) and those in the proportion of virus-infected rice hills were examined by regular field censuses during the period of 1964–69 at two localities in Kochi, Nangoku and Ino. The proportion of virus-infected insects in the vector population was measured by the serological test. Mean fecundity of adult females of N. cincticeps in different generations was assessed by the method proposed byHokyo andKiritani (1968) in 1966 and 1967. Using observed variables as mentioned above, two mathematical models were built up for the system of the natural spread of infection of RDV. Submodels describing generation-to-generation changes in densities of eggs, 1st instar nymphs and leafhopper adults were involved in both Models 1 and 2. In Model 1, the proportion (P) of infected insects in the vector population was assumed to be determined directly by the amount (I_v) of infected rice plants in the field. In Model 2, instead of relating P directly to I_v,P was related to the acquisition rate (W) of RDV by the insects and to the effect of RDV (αr) on fecundity and survival of infected insects. Then, W was related to I_v. The estimates of P by these models fitted well to the observed values for 1st to 3rd generations but a great deviation was noted in 4th and 5th generations. For the percentage of infected rice hills, both models gave relatively good estimates in the early planted rice, though they gave overestimated values in the late planted rice.     

Proteomic analysis of rice (Oryza sativa) seeds during germination

Although seed germination is a major subject in plant physiological research, there is still a long way to go to elucidate the mechanism of seed germination. Recently, functional genomic strategies have been applied to study the germination of plant seeds. Here, we conducted a proteomic analysis of seed germination in rice (Oryza sativa indica cv. 9311) - a model monocot. Comparison of 2-DE maps showed that there were 148 proteins displayed differently in the germination process of rice seeds. Among the changed proteins, 63 were down-regulated, 69 were up-regulated (including 20 induced proteins). The down-regulated proteins were mainly storage proteins, such as globulin and glutelin, and proteins associated with seed maturation, such as "early embryogenesis protein" and "late embryogenesis abundant protein", and proteins related to desiccation, such as "abscisic acid-induced protein" and "cold-regulated protein". The degradation of storage proteins mainly happened at the late stage of germination phase II (48 h imbibition), while that of seed maturation and desiccation associated proteins occurred at the early stage of phase II (24 h imbibition). In addition to alpha-amylase, the up-regulated proteins were mainly those involved in glycolysis such as UDP-glucose dehydrogenase, fructokinase, phosphoglucomutase, and pyruvate decarboxylase. The results reflected the possible biochemical and physiological processes of germination of rice seeds.     

Oxygen stress and adaptation of a semi-aquatic plant: rice ( Oryza sativa)

One of the major abiotic stresses that affects plant growth and development is anoxia or hypoxia. Rice is a semi-aquatic plant bestowed with the capability of overcoming oxygen limitation for a considerable period of time. For instance, it can withstand submergence stress either by inherent metabolic adaptations (resistant type), or by keeping its leaves above the water surface by continuously elongating the stem (avoiding type). In the former case, an interplay of several metabolic pathways engaged in anaerobic fermentation keeps the submerged plant alive for a certain period of time. In the latter type, also known as deepwater rice, continuous stem elongation brought about by a series of reactions in planta enables the shoot to remain above the water surface and thus maintain respiration and photosynthesis. However, the earliest event, i.e., sensing the oxygen level that brings about all the changes, has not been clearly understood. This paper intends to evaluate the metabolic adaptations of rice plants to oxygen constraints. Electronic Publication     

Fe^2＋诱发谷粒颖壳中乙烯释放和促进水稻幼苗生长的关系

Ｆｅ２＋ 可诱发水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）谷粒颖壳中释放大量乙烯,诱导反应是一个非酶促的化学过程。可能在谷粒颖壳中存在一种非气态的乙烯前体,在Ｆｅ２＋ 的作用下可转化为气态乙烯。Ｆｅ２＋ 促进水稻幼苗的生长可能是通过其诱导乙烯所引起的。因为Ｆｅ２＋ 诱发颖壳中的乙烯释放和它促进幼苗生长在时间上正好同步,当第一次处理后再更新Ｆｅ２＋ 溶液时,不再能诱发乙烯释放,也不再促进幼苗生长;Ｆｅ２＋ 不能刺激萌发糙米的乙烯产生,也不促进其幼苗生长     

水稻染色体G—带的研究

用改良的ASG法首次在籼稻(O.sativa subsp.indica)品种珍汕97和粳稻(O.subsp.iaponica)品种秀岭的有丝分裂染色体上显示了G-带,并作了相应的G-带核型分析。就同一材料来说,随着有丝分裂时期的推进,染色体上带纹数目逐渐减少。籼、粳亚种间相对应的同源染色体上G-带带纹特征彼此相似。讨论了水稻G-带带型与染色体不同区域分化的关系;G-带带型与籼、粳稻分歧的关系;以及G-显带的方法。     

差异显示法分离赤霉素调控的水稻(Oryza sativa)cDNA(英文)

赤霉素(gibberellins)是植物生长发育过程中一类重要的调节激素。本文运用反转录和聚合酶链式反应建立了一套旨在分离差异表达cDNA的差异显示方法。以籼稻珍汕97 B为材料,将赤霉素GA_3处理后的苗期水稻与对照的cDNA片段进行比较,鉴定了15个差异cDNA,并将它们从测序胶中回收和再次扩增获得差异表达的cDNA;用其中一个差异cDNA片段DDF1为探针的Southern和northern杂交证实,DDF1所对应的基因是一个单拷贝基因,可被高浓度的GA_3诱导并获得高水平表达。     

Competition among symbiotic cyanobacterial Nostoc strains forming artificial associations with rice (Oryza sativa)

Competition among four symbiotically competent Nostoc strains, colonizing rice roots, was examined using hetR-DGGE (denaturing gradient gel electrophoresis) as strain identification. Although mixed in various combinations, only one strain at a time associated with the rice roots. Nostoc strain 8964:3 was the most competitive and our data suggest that its competitive fitness was dependent on rapid hormogonial spreading as displayed on agar plates. Furthermore, rice roots induced hormogonia in all tested Nostoc strains, but only Nostoc strain 9104 showed positive chemotaxis towards the root. Inhibition of growth of competing cyanobacterial strains was not apparent.     

Natural parasitism of Romanomermis iyengari (Welch) (Nematoda: Mermithidae) on various species of mosquitoes breeding in rice fields in Pondicherry,India

Natural habitat of Romanomermis iyengari, an entomophilic mermithid nematode, is rice field. Parasitism of this nematode on mosquito larvae breeding in rice fields in Pondicherry, India, has been studied in 1979. The present study was to find out its persistence in the same habitat, after many years of agricultural practices. Evaluation of parasitism on mosquito larvae was carried out during two rice cultivation seasons at a schedule of 1 week prior, and 1 and 2 weeks after transplantation of paddy. Larval stages of mosquito species such as Culex tritaeniorhynchus, Culex vishnui, Anopheles vagus, and Anopheles subpictus showed parasitism of R. iyengari. Parasitism was the highest on C. tritaeniorhynchus with a maximum of 15.38% during season I and 17.85% during season II. Followed by this, it was on A. vagus (10.82% and 9.43%), C. vishnui (7.37% and 8.69%), and A. subpictus (3.70% and 6.36%). The overall density of mosquito larvae and level of parasitism of R. iyengari on them during season II was significantly higher than that of season I. The parasitism was maximum at 1 week before transplantation and showed a decreasing trend towards 2 weeks after transplantation, during both the seasons. The level of natural parasitism of R. iyengari during the present investigation was higher than that observed in the same ecosystem almost 35 years ago. This is clearly an indication towards the capability of the nematode to withstand several years of agricultural practices, including pesticide and agrichemical application. Hence, if applied at sufficient level and frequency, this nematode could act as a successful biocontrol agent against mosquitoes breeding in rice fields.     

Temperature-dependent development and oviposition models of Leptocorisa chinensis Dallas (Hemiptera: Alydidae)

Leptocorisa chinensis Dallas (Hemiptera: Alydidae) is known to cause pecky rice by sucking panicles of milk stage of rice. Based on its continuous spread and expanded damage area in Asian countries such as Japan with high reproduction potential, it is highly likely that L. chinensis will become an important rice pest in the near future. However, limited information is available to predict its distribution and occurrence. Thus, the objective of this study was to develop models for their development and oviposition. We investigated the development of L. chinensis immatures (from egg to adult) at 11 constant temperatures ranging from 16.2 to 35.3 °C and the oviposition of female adults at five constant temperatures ranging from 22.3 to 35.3 °C in this study. For L. chinensis immatures, the lower developmental threshold temperature, optimal developmental temperature, upper developmental threshold temperature were 12.7, 32.3, and 37.6 °C, respectively. The highest survival rate of immatures was observed at temperature of 25.2 °C and the highest mean total fecundity was 585.8 at 28.0 °C. This study provides basic information for the ecology of L. chinensis. It is applicable to forecast the phenology of its populations in the fields and to predict its future distribution under global warming.     

Heterotrophic nitrogen fixation (acetylene reduction) associated to flooded rice: A modified measurement technique in the field

A modifiedin situ technique for measuring heterotrophic nitrogen fixing (acetylene reducing) activity associated to rice is proposed. Ethylene evolution rates measured in opaque cylinders covering the stems of rice plants which have been cut 10 cm over the water level were found independent of the diurnal cycle. Cutting of the leaves resulted in decreased variation between plants and suppression of the acceleration of ethylene evolution rate after 12 h incubation as compared to intact plants. In both systems ethylene evolved was swept by a current of methane and the molar ratio between methane and ethylene was stabilized after 12 h. Methane evolution rates remained stable during 12 h and more than 24 h in whole plants and cut plants respectively. It is suggested that alteration in the active gas transport system after 12 h incubation under 10% acetylene may lead to erroneous evaluation of the actual ethylene production in the root's environment. The average values of ethylene evolution rates by cut plants between 12 and 24 h of incubation may be used for comparative studies of nitrogen fixing activity associated to flooded rice.     

Overview on current status of biotechnological interventions on yellow stem borer Scirpophaga incertulas (Lepidoptera: Crambidae) resistance in rice

Yellow stem borer (YSB), Scirpophaga incertulas (Lepidoptera: Crambidae), a monophagous pest of paddy is considered as most important pest of rain fed low land and flood prone rice eco-systems. Breeding of yellow stem borer resistance in rice is difficult owing to the complex genetics of the trait, inherent difficulties in screening and poor understanding of the genetics of resistance. On the other hand, a good level of resistance against the widespread yellow stem borer has been rare in the rice germplasm. Resistance to insects has been demonstrated in transgenic plants expressing genes for δ-endotoxins from Bacillus thuringiensis (Bt), protease inhibitors, enzymes and plant lectins. The performance of insect resistant GM rice in trials in China has been quite impressive. The present review is an attempt to assess the current state of development in biotechnological intervention for yellow stem borer resistance in rice.     

水稻体细胞无性系变异

水稻体细胞无性系变异研究取得了很大进展 ,获得了大量抗病、抗逆、优质、矮杆等突变体。对这些突变体遗传分析表明 ,大多数突变性状由 1对或 2对基因控制。水稻体细胞无性系变异的发生与基因型、性状、继代时间、培养方式等有关 ,并具有内在的机制 ,点突变和反转录转座子插入可能是引起水稻无性系变异的两个重要原因。     

Identification of egg parasitoids of rice leafhoppers and planthoppers (Hemiptera: Cicadellidae and Delphacidae) of economic importance in Taiwan,part 1: Mymaridae (Hymenoptera)

Fairyfly egg parasitoids (Hymenoptera: Mymaridae) of rice leafhoppers and planthoppers (Hemiptera: Cicadellidae and Delphacidae) known from Taiwan are identified taxonomically, keyed, and illustrated. Their host associations are determined by rearings using sentinel eggs of mainly four key pest species. The previously published records of such egg parasitoids in Taiwan are critically analyzed in the unfortunate absence of almost any voucher specimens. Three species of Mymaridae are shown to be the predominant egg parasitoids of one leafhopper and three planthopper major pests of rice in Taiwan: Anagrus (Anagrus) incarnatus Haliday of the green rice leafhopper Nephotettix cincticeps (Uhler) and the delphacids Laodelphax striatella (Fallén) (small brown planthopper), Nilaparvata lugens (Stål) (brown planthopper), and Sogatella furcifera (Horváth) (whitebacked planthopper), as well as Gonatocerus aegyptiacus Soyka and Mymar taprobanicum Ward of N. cincticeps. The zig-zag leafhopper Maiestas dorsalis (Motschulsky), which is also common in paddy fields, is newly recorded as a host for A. incarnatus, G. aegyptiacus, Lymaenon litoralis (Haliday), and M. taprobanicum. Additional new records of some other Mymaridae in Taiwan, mostly from the rice field agroecosystems, are indicated. Litus assamensis Rehmat and Anis, syn. nov. from India, is synonymized with L. sutil Triapitsyn and Berezovskiy from Thailand, which is also newly recorded from Taiwan.     

Bioremediation of kerosene II: a case study in contaminated clay (Laboratory and field: scale microcosms)

Kerosene contaminated clay results in large amounts from the treatment of Jet kerosene produced from Merox process, in the Middle East Operation and Maintenance for Oil Refineries (MIDOR), Alexandria and represent a great environmental pollution problem. The treatment of the clay was performed with natural attenuation, biostimulation and bioaugmentation in lab and field-scale microcosms. More than 90% of the kerosene was biodegraded in bioaugmentation and biostimulation processes, while only 50% was obtained by natural attenuation after seven weeks. Urea 46% and superphosphate 15.5% were used as nitrogen and phosphorus sources due to their low cost and local availability. The immobilized cells enhanced the biodegradation processes and reduced the time. Dehydrogenase activity was affected by the time and type of the treatment. The degradation percent was found to be 85–90% at temperature range 21–24°C, while only 57–68% was obtained at temperature 15–17°C. The lab-scale microcosm was scaled up to field microcosm with a great success.     

Influence of temperature on the northern distribution limits of Scirpophaga incertulas Walker (Lepidoptera: Pyralidae) in China

We explored the influence of temperature on the northern distribution limits of Scirpophaga incertulas Walker, an important agricultural pest of rice in Asia. We analyzed ≥48 years of records from 186 climate stations of Mainland China to estimate the annual probabilities of reaching the lower lethal temperature for S. incertulas. The relevant climatic metric, minimum annual temperature, approximated a normal distribution. Consequently, the probability density function for any site could be characterized with the mean and standard deviation of minimum annual temperatures. We used the local regression method to map the mean and standard deviation of minimum annual temperatures throughout Mainland China and then calculated isolines representing annual probabilities for reaching or exceeding the lower lethal temperature of S. incertulas. In addition, we calculated and mapped the number of generations per year based on the annual accumulative degree days and the sum of effective temperatures required to complete one generation. The empirical northern distribution limits of S. incertulas were generally congruent with the theoretical limits based on winter survival, with exceptions within the Shandong and Sichuan provinces, which are apparently thermally suitable but where the host plant is not cultivated. The expected number of generations per year was 3–5 within most of the range of S. incertulas in China. In central China, the expected number of generations per year was about 3. A climate warming scenario of 4 °C in minimum and maximum daily temperatures predicted an increase in the expected number of generations per year in central China from about 3 to 4.     

Juvenile hormone-mediated reproduction induced by a sublethal concentration of imidacloprid in Cyrtorhinus lividipennis (Hemiptera: Miridae)

The Hemipteran predator, Cyrtorhinus lividipennis, feeds on the eggs and nymphs of rice planthoppers and leafhoppers. We previously demonstrated that sublethal concentrations of imidacloprid stimulated the reproduction of C. lividipennis. Considering the essential roles of juvenile hormone (JH) in insect reproduction, we speculated that sublethal concentrations of imidacloprid may stimulate the reproduction of C. lividipennis by regulating JH level. To test this, we cloned C. lividipennis JH acid methyl transferase (ClJHAMT) and JH esterase (ClJHE), which are responsible for JH biosynthesis and degradation genes, respectively. We then knocked down ClJHAMT by injecting dsRNA into C. lividipennis nymphs and found that emerging female adults exhibited 88.8% lower expression of the vitellogenin gene (ClVg) and the number of eggs was reduced by 41.5% as compared with controls. Silencing ClJHE increased ClVg mRNA expression by 275.0% but did not affect fecundity. A sublethal concentration of imidacloprid (LC₂₀) increased the JH titer in females by 35.3% and 60.6% at 24 and 48 h post-emergence, respectively. In treatments containing both imidacloprid and dsJHAMT, the silencing of CLJHAMT reduced the number of eggs produced by adult females by 21.4% as compared to the control (imidacloprid + dsGFP). Our results indicated that sublethal concentration of imidacloprid may induce C. lividipennis reproduction by upregulating JH level via JHAMT. The finding could provide valuable information for improved integration of C. lividipennis and insecticides in pest management.