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1.
【目的】检测 Q 型烟粉虱 Bemisia tabaci (Gennadius)体内 Rickettsia 的感染情况,研究分析Rickettsia 共生菌经烟粉虱传入豇豆植物后的分布、转移效率等。【方法】以 Q 型烟粉虱为实验材料,利用常规 PCR 及荧光原位杂交技术(FISH),检测了烟粉虱体内 Rickettsia 的感染率,以及 Rickettsia 传入豇豆植物体内后的存留情况。【结果】 Q 型烟粉虱可以通过取食将 Rickettsia 传至豇豆植株内;接虫数量与 Rickettsia传入效率及其在取食部位相邻的下部叶片中检测到的起始时间呈负相关;Rickettsia 经烟粉虱取食传入豇豆叶片后,集中分布在叶片的韧皮部筛管中;基于16S rRNA 的系统发育分析结果表明,Q 型烟粉虱体内的Rickettsia 与经取食传入豇豆叶片的 Rickettsia 高度同源。【结论】 Rickettsia 可以通过烟粉虱的取食传入植物体内,并且可以在相邻叶片之间转移传播,Rickettsia 在由寄主昆虫向植株传播过程中高度保守。  相似文献   
2.
The feeding behavior of Diuraphis noxia Mordvilko (Homoptera: Aphididae) on susceptible hosts causes both ultrastructural and tissue level damage which may affect phloem composition. Genetic evidence suggests that endosymbiotic bacteria in most aphids overproduce limiting amino acids to benefit hosts but that D. noxia depends less on endosymbionts for these nutrients, possibly due to an enriched diet. To determine whether D. noxia feeding damage results in higher concentrations of essential amino acids, stylet exudates were analyzed from wheat (Triticum aestivum) damaged to different degrees. Comparison of samples from undamaged and damaged susceptible wheat revealed changes in amino acid composition and an increase in levels of essential amino acids, indicating a nutritionally enhanced ingesta. The changes in stylet exudates paralleled changes in leaf exudates, indicating that the effects are systemic. Feeding damage is not observed on a resistant wheat host, var. Halt, and leaf exudates from infested Halt did not show changes in amino acid composition. Mean relative growth of nymphs was significantly lower on Halt than on susceptible Arapahoe, indicating that Halt is a less suitable host. Both varieties show similar amino acid levels in non-infested samples, suggesting that D. noxia infestation does not enhance the phloem environment in Halt. This study provides evidence that aphid feeding can generate a nutritionally enhanced phloem diet.  相似文献   
3.
昆虫传播的植物病毒种类多、危害大,其传病毒的能力与昆虫体内共生菌产生的GroEL蛋白关系密切,该蛋白是分子伴侣hsp60家族的成员,对病毒进入昆虫血体腔免遭破坏起着保护作用,也与昆虫传病毒的专一性有关。本对昆虫内共生菌及其产生的GroEL进行了综述,并分析了研究内共生菌及其产生的蛋白质的科学意义与发展趋势,为植物病毒病的防治研究提供了新的思路。  相似文献   
4.
Four strains, coded as UPM1132, UPM1133T, UPM1134 and UPM1135, and isolated from nodules of Pisum sativum plants grown on Ni-rich soils were characterised through a polyphasic taxonomy approach. Their 16S rRNA gene sequences were identical and showed 100% similarity with their closest phylogenetic neighbors, the species included in the ‘R. leguminosarum group’: R. laguerreae FB206T, R. leguminosarum USDA 2370T, R. anhuiense CCBAU 23252T, R. sophoreae CCBAU 03386T, R. acidisoli FH13T and R. hidalgonense FH14T, and 99.6% sequence similarity with R. esperanzae CNPSo 668T. The analysis of combined housekeeping genes recA, atpD and glnII sequences showed similarities of 92-95% with the closest relatives. Whole genome average nucleotide identity (ANI) values were 97.5-99.7% ANIb similarity among the four strains, and less than 92.4% with closely related species, while digital DNA-DNA hybridization average values (dDDH) were 82-85% within our strains and 34-52% with closely related species. Major fatty acids in strain UPM1133T were C18:1 ω7c / C18:1 ω6c in summed feature 8, C14:0 3OH/ C16:1 iso I in summed feature 2 and C18:0. Colonies were small to medium, pearl-white coloured in YMA at 28 °C and growth was observed in the ranges 8-34 °C, pH 5.5-7.5 and 0-0.7% (w/v) NaCl. The DNA G + C content was 60.8 mol %. The combined genotypic, phenotypic and chemotaxonomic data support the classification of strains UPM1132, UPM1133T, UPM1134 and UPM1135 into a novel species of Rhizobium, for which the name Rhizobium ruizarguesonis sp. nov. is proposed. The type strain is UPM1133T (=CECT 9542T = LMG 30526T).  相似文献   
5.
利用烟粉虱Bemisia tabaci(Gennadius)内共生菌特异性引物,研究了内共生菌在B、Q型烟粉虱种群中的分布和感染率,同时评价了3种不同的抗生素利福平、氨苄青霉素和硫酸卡那霉素分别在3种不同的浓度下(100.0、50.0及25.0μg/mL)对烟粉虱内共生菌的去除效果。结果表明:B、Q型烟粉虱原生内共生细菌Portiera的带菌率均为100.0%;B、Q型烟粉虱次生内共生菌Hamiltonella的带菌率分别为91.7%和100.0%;B型烟粉虱次生内共生菌Rickettsia的带菌率为87.5%,Q型为0;其它次生内共生菌在B、Q型烟粉虱中均未检测到。利福平、氨苄青霉素和硫酸卡那霉素在3种不同的浓度下均不能去除B、Q型烟粉虱Portiera;利福平、氨苄青霉素在3种不同的浓度下均能完全去除B型烟粉虱Rickettsia,硫酸卡那霉素在不同浓度下去除Rickettsia的效果不同;3种抗生素去除Hamiltonella的能力受抗生素种类以及浓度的影响。同一抗生素在不同浓度下去除Hamiltonella的效果均是100.0μg/mL>50.0μg/mL>25.0μg/mL;不同浓度的抗生素去除Hamiltonella的效果均是利福平>氨苄青霉素>硫酸卡那霉素,各浓度与各抗生素之间的去除Hamiltonella的效果均具有显著性差异。  相似文献   
6.
Wolbachia is a genus of intracellular bacteria typically found within the reproductive systems of insects that manipulates those systems of their hosts. While current estimates of Wolbachia incidence suggest that it infects approximately half of all arthropod species, these estimates are based almost entirely on terrestrial insects. No systematic survey of Wolbachia in aquatic insects has been performed. To estimate Wolbachia incidence among aquatic insect species, we combined field‐collected samples from the Missouri River (251 samples from 58 species) with a global database from previously published surveys. The final database contained 5,598 samples of 2,687 total species (228 aquatic and 2,459 terrestrial). We estimate that 52% (95% CrIs: 44%–60%) of aquatic insect species carry Wolbachia, compared to 60% (58%–63%) of terrestrial insects. Among aquatic insects, infected orders included Odonata, Coleoptera, Trichoptera, Ephemeroptera, Diptera, Hemiptera, and Plecoptera. Incidence was highest within aquatic Diptera and Hemiptera (69%), Odonata (50%), and Coleoptera (53%), and was lowest within Ephemeroptera (13%). These results indicate that Wolbachia is common among aquatic insects, but incidence varies widely across orders and is especially uncertain in those orders with low sample sizes such as Ephemeroptera, Plecoptera, and Trichoptera.  相似文献   
7.
Gymnodinium aeruginosum has the usual fine structure of a dinoflagellate but does not seem to contain a well elaborated peduncle or a microtubular basket. Naked cells are surrounded by a single large amphiesmal vesicle. It houses an endosymbiont with typical blue-green cryptophycean chloroplasts (generally only one), cryptophycean starch grains in the periplastidal cytoplasm without a nucleomorph, and two membranes separating the periplastidal cytoplasm from the cryptophycean cytoplasm which contains mitochondria, ER, vesicles and ribosomes, but no eukaryotic nucleus. The endosymbiont is surrounded by a single membrane. Possible ways of the acquisition of the endosymbiont and the problem of the existence of ribosomes within a compartment without nucleus are discussed.Devoted to Prof. Dr.L. Geitler, the Nestor of phycology and endosymbiosis research, on the occasion of the 90th anniversary of his birthday.  相似文献   
8.
It is now clear that mechanisms of sex determination are extraordinarily labile, with considerable variation across all taxonomic levels. This variation is often expressed through differences in the genetic system (XX‐XY, XX‐XO, haplodiploidy, and so on). Why there is so much variation in such a seemingly fundamental process has attracted much attention, with recent ideas concentrating on the possible role of genomic conflicts of interest. Here we consider the role of inter‐ and intra‐genomic conflicts in one large insect taxon: the scale insects. Scale insects exhibit a dizzying array of genetic systems, and their biology promotes conflicts of interest over transmission and sex ratio between male‐ and female‐expressed genes, parental‐ and offspring‐expressed genes (both examples of intra‐genomic conflict) and between scale insects and their endosymbionts (inter‐genomic conflict). We first review the wide range of genetic systems found in scale insects and the possible evolutionary transitions between them. We then outline the theoretical opportunities for genomic conflicts in this group and how these might influence sex determination and sex ratio. We then consider the evidence for these conflicts in the evolution of sex determination in scale insects. Importantly, the evolution of novel genetic systems in scale insects has itself helped create new conflicts of interest, for instance over sex ratio. As a result, a major obstacle to our understanding of the role of conflict in the evolution of sex‐determination and genetic systems will be the difficulty in identifying the direction of causal relationships. We conclude by outlining possible experimental and comparative approaches to test more effectively how important genomic conflicts have been.  相似文献   
9.
Eggs of leaf beetles of the tribe Galerucini, subfamily Galerucinae, contain polyketides that are unusual in insects: 1,8-dihydroxylated anthraquinones (chrysazin, chrysophanol) and anthrones (dithranol, chrysarobin) deterring predators. The host plants do not contain these compounds. In the present study, we tested the hypothesis that the beetles, but not bacterial or fungal microorganisms living as endosymbionts within the beetles, produce the anthraquinones. The tansy leaf beetle Galeruca tanaceti was used as Galerucini model organism. It was treated with antimicrobial substances to eradicate the microorganisms and inhibit the hypothesised endosymbiotic anthraquinone production. Despite treatment, female G. tanaceti laid eggs containing anthraquinones. Although broad spectrum antimicrobials were used, it cannot be excluded that the potential endosymbiotic microorganisms are resistant. Given that the hypothesised endosymbionts are transferred via the eggs from one generation to the next, bacterial or fungal DNA was expected to be present in the eggs. With the exception of Wolbachia pipientis, however, no further 16S rDNA from bacteria responsible for anthraquinone biosynthesis was detected in eggs of untreated beetles. Because Wolbachia were also found in closely related anthraquinone-free insects, we exclude these bacteria as producers of the defensive polyketides. Nor was any 18S rDNA from fungi with anthraquinone biosynthetic abilities detected. Our results indicate that anthraquinones and anthrones in eggs of Galerucini are produced by beetle enzymes and not by endosymbiotic microorganisms within the eggs.  相似文献   
10.
A+T content, phylogenetic relationships, codon usage, evolutionary rates, and ratio of synonymous versus non-synonymous substitutions have been studied in partial sequences of the atpD and aroQ/pheA genes of primary (Buchnera) and secondary symbionts of aphids and a set of selected non-symbiotic bacteria, belonging to the five subdivisions of the Proteobacteria. Compared to the homologous genes of the last group, both genes belonging to Buchnera behave in a similar way, showing a higher A+T content, forming a monophyletic group, a loss in codon bias, especially in third base position, an evolutionary acceleration and an increase in the number of non-synonymous substitutions, confirming previous results reported elsewhere for other genes. When available, these properties have been partly observed with the secondary symbionts, but with values that are intermediate between Buchnera and free living Proteobacteria. They show high A+T content, but not as high as Buchnera, a non-solved phylogenetic position between Buchnera, and the other γ-Proteobacteria, a loss in codon bias, again not as high as in Buchnera and a significant evolutionary acceleration in the case of the three atpD genes, but not when considering aroQ/pheA genes. These results give support to the hypothesis that they are symbionts at different stages of the symbiotic accommodation to the host.  相似文献   
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