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1.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.  相似文献   

2.
Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is already successfully used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in protected crops. In the present work, the predatory capacity of O. laevigatus on the eggs and larvae of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) as well as the population growth capacity of O. laevigatus fed on eggs of the noctuid were determined. Fourth and 5th instar nymphs had a greater consumption of eggs than younger ones. Females consumed more eggs than males. Only 5th instar nymphs and adults preyed on the neonatal larvae of S. exigua. The intrinsic rate of natural increase did not differ between O. laevigatus fed with S. exigua eggs and those offered eggs of the substitute host Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). Thus, O. laevigatus is a good candidate for the biological control of S. exigua, a cosmopolitan pest of many crops.  相似文献   

3.
A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.  相似文献   

4.
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.  相似文献   

5.
New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.  相似文献   

6.
Recently, the prenyltransferase SirD was found to be responsible for the O-prenylation of tyrosine in the biosynthesis of sirodesmin PL in Leptosphaeria maculans. In this study, the behavior of SirD towards phenylalanine/tyrosine and tryptophan derivatives was investigated. Product formation has been observed with 12 of 19 phenylalanine/tyrosine derivatives. It was shown that the alanine structure attached to the benzene ring and an electron donor, e.g., OH or NH2, at its para-position are essential for the enzyme activity. Modifications were possible both at the side chain and the benzene ring. Enzyme products from seven phenylalanine/tyrosine derivatives were isolated and characterized by MS and NMR analyses including HSQC and HMBC and proven to be O- or N-prenylated derivatives at position C4 of the benzene rings. K M values of six selected derivatives were found in the range of 0.10–0.68 mM. Catalytic efficiencies (K cat/K M ) were determined in the range of 430–1,110 s−1·M−1 with l-tyrosine as the best substrate. In addition, 7 of 14 tested tryptophan analogs were also accepted by SirD and converted to C7-prenylated derivatives, which was confirmed by comparison with products obtained from enzyme assays using a 7-dimethylallyltryptophan synthase 7-DMATS from Aspergillus fumigatus.  相似文献   

7.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.  相似文献   

8.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.  相似文献   

9.
Tropilaelaps mercedesae is a serious ectoparasite of Apis mellifera in China. The aim of this study was to investigate the infestation rates and intensity of T. mercedesae in A. mellifera in China, and to explore the relative importance of climate, district, management practices and beekeeper characteristics that are assumed to be associated with the intensity of T. mercedesae. Of the 410 participating apiaries, 379 apiaries were included in analyses of seasonal infestation rates and 352 apiaries were included in multivariable regression analysis. The highest infestation rate (86.3%) of T. mercedesae was encountered in autumn, followed by summer (66.5%), spring (17.2%) and winter (14.8%). In autumn, 28.9% (93) of the infested apiaries were in the north (including the northeast and northwest of China), 71.1% (229) were in the central and south (including east, southeast and southwest China), and 306 apiaries (82.9%) were co-infested by both T. mercedesae and Varroa. Multivariable regression analysis showed that geographical location, season, royal jelly collection and Varroa infestation were the factors that influence the intensity of T. mercedesae. The influence of beekeeper’s education, time of beekeeping, operation size, and hive migration on the intensity of T. mercedesa was not statistically significant. This study provided information about the establishment of the linkage of the environment and the parasite and could lead to better timing and methods of control.  相似文献   

10.
The predation capacity and prey preference of larvae of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) on eggs or larvae of Pieris brassicae (Linnaeus) (Lepidoptera: Pieridae) in the absence and presence of cabbage aphids as an alternative prey were evaluated in laboratory experiments at 25°C. Both instars preyed upon butterfly eggs and larvae as well as on cabbage aphids with the third instar being the most voracious. The lacewings had a strong preference for caterpillars to butterfly eggs. In the presence of the aphids the predation on P. brassicae eggs or larvae was either completely abandoned or reduced by about 70%, respectively, by second instar lacewings and either reduced by about 80% or maintained, respectively, by third instar lacewings. Both instars thus had a clear preference for aphids compared to eggs of P. brassicae. However, second instar lacewings preferred aphids to caterpillars whereas the opposite was the case for third instar lacewings. The results indicate that 3rd instar C. carnea has a potential as biocontrol agent against P. brassicae.  相似文献   

11.
12.
Development and reproduction of the predatory mite Parasitus consanguineus Oudemans et Voigts (Acari: Parasitidae) reared on a diet of first and second instars of Megaselia halterata (Diptera: Phoridae) or Lycoriella ingenua (Diptera: Sciaridae) were studied. Mites were allowed to feed on these diets until death. The developmental time of immature stages of P. consanguineus was significantly longer when reared on L. ingenua than on M. halterata larvae (8.3 vs. 7.9 days, respectively). Survival to adulthood of P. consanguineus reared on L. ingenua or M. halterata larvae was 63 and 49%, and mite fecundity was 17.8 and 12.3 eggs/female, respectively. Adult females reared on L. ingenua lived on average 6.9 days, whereas those reared on M. halterata lived for 5.7 days. Mite survival, female longevity and fecundity were significantly different among the two diet types.  相似文献   

13.
14.
Ogataea parapolymorpha sp. n. (NRRL YB-1982, CBS 12304, type strain), the ascosporic state of Candida parapolymorpha, is described. The species appears homothallic, assimilates methanol as is typical of most Ogataea species and forms hat-shaped ascospores in asci that become deliquescent. O. parapolymorpha is closely related to Ogataea angusta and Ogataea polymorpha. The three species can be resolved from gene sequence analyses but are unresolved from fermentation and growth reactions that are typically used for yeast identification. On the basis of multiple isolates, O. angusta is known only from California, USA, in association with Drosophila and Aulacigaster flies, O. parapolymorpha is predominantly associated with insect frass from trees in the eastern USA but O. polymorpha has been isolated from various substrates in the USA, Brazil, Spain and Costa Rica.  相似文献   

15.
Endosymbiotic bacteria that potentially influence reproduction and other fitness-related traits of their hosts are widespread in insects and mites and their appeal to researchers’ interest is still increasing. We screened 20 strains of 12 agriculturally relevant herbivorous and predatory mite species for infection with Wolbachia, Cardinium and Spiroplasma by the use of PCR. The majority of specimens originated from Austria and were field collected or mass-reared. Eight out of 20 strains (40%) tested, representing seven of 12 mite species (58%), carried at least one of the three bacteria. We found Wolbachia in the herbivorous spider mites Tetranychus urticae and Bryobia rubrioculus, with the former also carrying Spiroplasma and the latter also carrying Cardinium. Cardinium was furthermore found in two populations of the predatory mite Euseius finlandicus and the spider mite Eotetranychus uncatus. Spiroplasma was detected in the predatory mite Neoseiulus californicus. All bacteria positive PCR products were sequenced, submitted to GenBank and analyzed in BLAST queries. We found high similarities to complete identity with bacteria found in the same and different mite species but also with bacteria found in insect species like ladybirds, butterflies and minute pirate bugs, Orius. We discuss the significance of potential (multiple) infections with the investigated bacteria for biological control.  相似文献   

16.
Seol E  Jung Y  Lee J  Cho C  Kim T  Rhee Y  Lee S 《Plant cell reports》2008,27(7):1197-1206
Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.  相似文献   

17.
A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan  相似文献   

18.
Tuber huidongense and T. liyuanum are common commercial white truffles in China that belong to the Rufum and Puberulum groups of the genus Tuber, respectively. Their mycorrhizae were successfully synthesized with two native trees—Castanea mollissima and Pinus armandii—under greenhouse conditions. The identities of the mycorrhizae were confirmed through internal transcribed spacer (ITS) sequence analyses, and their morphological characteristics were described. All of the obtained mycorrhizae have an interlocking pseudoparenchymatous mantle, which is a typical feature of truffle mycorrhizae. The mycorrhizae of T. huidongense on the two trees have hyaline branched emanating hyphae, similar to the documented mycorrhizae of the Rufum group. The unramified, spiky, and hyaline cystidia on the mycorrhizae of T. liyuanum with both C. mollissima and P. armandii further confirmed that this characteristic is constant for the mycorrhizae of the Puberulum group. The successful mycorrhizal syntheses on the two nut-producing trees will be of economic importance in the cultivation of the two truffles.  相似文献   

19.
The B subfamily of ATP-binding cassette (ABC) proteins (ABCB) plays a vital role in auxin efflux. However, no systematic study has been done in apple. In this study, we performed genomewide identification and expression analyses of the ABCB family in Malus domestica for the first time. We identified a total of 25 apple ABCBs that were divided into three clusters based on the phylogenetic analysis. Most ABCBs within the same cluster demonstrated a similar exon–intron organization. Additionally, the digital expression profiles of ABCB genes shed light on their functional divergence. ABCB1 and ABCB19 are two well-studied auxin efflux carrier genes, and we found that their expression levels are higher in young shoots of M106 than in young shoots of M9. Since young shoots are the main source of auxin synthesis and auxin efflux involves in tree height control. This suggests that ABCB1 and ABCB19 may also take a part in the auxin efflux and tree height control in apple.  相似文献   

20.
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