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51.
Runchun Jing Alexander Vershinin Jacek Grzebyta Paul Shaw Petr Smýkal David Marshall Michael J Ambrose TH Noel Ellis Andrew J Flavell 《BMC evolutionary biology》2010,10(1):44
Background
The genetic diversity of crop species is the result of natural selection on the wild progenitor and human intervention by ancient and modern farmers and breeders. The genomes of modern cultivars, old cultivated landraces, ecotypes and wild relatives reflect the effects of these forces and provide insights into germplasm structural diversity, the geographical dimension to species diversity and the process of domestication of wild organisms. This issue is also of great practical importance for crop improvement because wild germplasm represents a rich potential source of useful under-exploited alleles or allele combinations. The aim of the present study was to analyse a major Pisum germplasm collection to gain a broad understanding of the diversity and evolution of Pisum and provide a new rational framework for designing germplasm core collections of the genus. 相似文献52.
Koskela S Söderholm PP Ainasoja M Wennberg T Klika KD Ovcharenko VV Kylänlahti I Auerma T Yli-Kauhaluoma J Pihlaja K Vuorela PM Teeri TH 《Planta》2011,233(1):37-48
A previously isolated cDNA molecule from Gerbera hybrida (Asteraceae) codes for a new chalcone synthase-like polyketide synthase, 2-pyrone synthase (2PS). 2PS is able to synthesise 4-hydroxy-6-methyl-2-pyrone (triacetolactone), a putative precursor for gerberin and parasorboside, two abundant glucosides in gerbera. In this study, we show that gerbera plants transformed with the gene for 2PS in an antisense orientation and unable to synthesise gerberin and parasorboside are susceptible to Botrytis cinerea infection. In addition to the preformed glucosides, the transgenic plants also lack several compounds that are induced in control plants when infected with the mould. Some of these induced substances are effective in inhibiting fungal growth both in vitro and in vivo. Two of the phytoalexins were identified as the aglycones of gerberin and trans-parasorboside. The third phytoalexin is a rare coumarin, 4-hydroxy-5-methylcoumarin; however, it is typical of many plants of the sunflower family Asteraceae. The coumarin cannot be structurally derived from either gerberin or parasorboside, but may be derived from a related polyketide intermediate. 相似文献
53.
Directed immobilization of recombinant staphylococci on cotton fibers by functional display of a fungal cellulose-binding domain 总被引:5,自引:0,他引:5
The immobilization of recombinant staphylococci onto cellulose fibers through surface display of a fungal cellulose-binding domain (CBD) was investigated. Chimeric proteins containing the CBD from Trichoderma reesei cellulase Cel6A were found to be correctly targeted to the cell wall of Staphylococcus carnosus cells, since full-length proteins could be extracted and affinity-purified. Furthermore, surface accessibility of the CBD was verified using a monoclonal antibody and functionality in terms of cellulose-binding was demonstrated in two different assays in which recombinant staphylococci were found to efficiently bind to cotton fibers. The implications of this strategy of directed immobilization for the generation of whole-cell microbial tools for different applications will be discussed. 相似文献
54.
C. TH. Buchelos C. G. Athanassiou C. CH. Papapostolou A. Georgiou 《Journal of Applied Entomology》1999,123(7):433-436
In order to evaluate the influence of the number of catches in pheromone-baited traps on the percentage of larval infestation, six delta traps equipped with sex attractant were placed in each of three regions in Central Greece (Farkadona, Farsala, Almyros) in cotton fields from 20 June until 30 September 1995. The collection of fruiting bodies took place weekly and the counting of adults in the traps was carried out each day. The population fluctuation in all three regions was similar with their peak during the first weeks of August. In Farkadona the infestation level was low (1% at the first sampling of August) with a maximum of 9% in the last sampling of September. In Farsala and Almyros, the infestation level was already high (10% and above) in early August. There was a significant positive linear correlation between the number of moth catches and the infestation percentage from first- and second-stage larvae on the first (R = 0694) and second (R = 0.7399) boll-feeding generations. 相似文献
55.
LAZARIDOU-DIMITRIADOU M.; ALPOYANNI E.; BAKA M.; BROUZIOTIS TH.; KIFONIDIS N.; MIHALOUDI E.; SIOULA D.; VELLIS G. 《Journal of Molluscan Studies》1998,64(1):67-74
This paper examines the optimum conditions for edible snailsHelix aspersa to be cultured indoors successfully in successivegenerations (originating from the crossing of snails comingfrom different clutches of a previous generation), and the effectof crowding on growth and reproduction in fast-, medium-, andslow-growing snails coming from the same clutches. The timeneeded for the snails to reach marketable size (2532mm)varied from 2.5 to 5 months up to the 7th generation. The timeneeded for the snails to mature and reproduce from 4 to 7 monthsuntil the fifth generation. After the F5 x F5 generation, thefinal size of the snails decreased. The number of eggs did notdiffer statistically among the different generations but thereproductive success (how many snails reproduced/cage) increasedfrom Fl = Fl generation onwards to F5 x F5. In F6 x F6 onlythree (out of 26) snails reproduced and in F7 x F7 none, althoughthe snails remained under controlled conditions for 15 moremonths. Mortality in the different generations varied from 010%up to F5 x F5 but from F6 x F6 onwards increased and reached25%. Concerning the origin of snails, it was found that largersnails (originating from Kyparissia, Peloponnesos) lay statisticallymore eggs (138.40 ± 29.60, N =5) than smaller ones (77.38± 40.42, N=4) (originating from Hania, island of Crete).Hatching success was greater, too. (Received 10 September 1996; accepted 24 March 1997) 相似文献
56.
Erkki Truve Lenne Nigul Teemu H. Teeri Merike Kelve 《Nucleosides, nucleotides & nucleic acids》2013,32(5):1097-1111
Abstract Nonphosphorylated 2-5A inhibited translation and caused RNA degradation in wheat germ extract, whereas 3-5A had no effect. Protein synthesis inhibition by 2-5A was observed in tobacco protoplasts. 70 kD 2-5A-binding protein was found in potato leaf extracts by chemical crosslinking. 相似文献
57.
Effects of Nuclear and Cytoplasmic Genes Altering Chlorophyll Loss on Gas Exchange during Monocarpic Senescence in Soybean 总被引:5,自引:0,他引:5
Several genes can alter the yellowing processes that normallyoccur during pod development and monocarpic senescence in soybean.CytG and d1 + d2 cause the leaves and seeds to stay green atmaturity. G blocks yellowing of the seed coat but not the leavesor embryos. By contrast, another gene, y3, causes earlier yellowingof the leaves. This paper examines the effects of these geneson photosynthesis and some related parameters of the senescencesyndrome in near-isogenic backgrounds (cv. Clark). Neither cytGnor d1 d2 delays the decline in photosynthetic rate during monocarpicsenescence relative to Clark; while Gd1 d2 does. Again, y3 causesan earlier decrease. Similarly, neither cytG nor d1 d2 altersthe decline in stomatal conductance and transpiration, whichoccurs at the end of podfill; however, Gd1 d2 delays it andy3 advances it. Neither cytG nor d1 d2 prevents the rise inintercellular CO2 during podfill, while Gd1 d2 does, and y3promotesit. These changes in intercellular CO2 may reciprocally reflectthe status (maintenance for Gd1 d2 and early loss for y3) ofthe photosynthetic enzymes. Gd1 d2, d1 d2 and cytG do not appreciablyaffect leaf blade abscission; however, y3 prevents it. Gd1 d2increases the dry weight seed yield, and y3 decreases it. Gd1d2 inhibits several components in the senescence process, whilecytG seems to affect mainly chlorophyll loss and y3 may actmore broadly than just accelerating senescence. Clearly, thestay-green trait can be caused by more than one genetic locus,and it may or may not maintain photosynthesis.
3Present address: Instituto de Fisologia Vegetal, Facultad deAgronomia, c.c. 31, 1900-La Plata, Argentina (Received May 18, 1990; Accepted September 4, 1990) 相似文献
58.
Paula Elomaa Yrjö Helariutta Mika Kotilainen Teemu H. Teeri Robert J. Griesbach Pauli Seppänen 《Molecular & general genetics : MGG》1995,248(6):649-656
Petunia mutant RL01 was transformed with maizeA1 and gerberagdfr cDNAs, which both encode dihydroflavonol-4-reductase (DFR) activity. The sameAgrobacterium vector and the same version of the CaMV 35S promoter were used in both experiments. Transformation with the cDNAs resulted in production of pelargonidin pigments in the transformants. However, theA1 andgdfr transformants showed clearly different phenotypes. The flowers of the primaryA1 transformants were pale and showed variability in pigmentation during their growth, while the flowers of thegdfr transformants showed intense and highly stable coloration. The color difference in the primary transformants was reflected in the expression levels of the transgenes as well as in the levels of anthocyanin pigment. As previously reported by others, the instability in pigmentation in theA1 transformants was more often detected in clones with multiple copies of the transgene and was associated with methylation of the 35S promoter and of the transgene cDNA itself. In thegdfr transformants, the most intense pigmentation was observed in plants with multiple transgenes in their genome. Only rarely was partial methylation of the 35S promoter detected, while thegdfr cDNA always remained in an unmethylated state. We conclude that the properties of the transgene itself strongly influence the inactivation process. The dicotyledonousgdfr cDNA with a lower GC content and fewer possible methylation sites is more compatible the genomic organization of petunia and this prevents it being recognized as a foreign gene and hence silenced by methylation. 相似文献
59.
M. E. Kubiske Kurt S. Pregitzer Carl J. Mikan Donald R. Zak Jennifer L. Maziasz A. Teeri 《Oecologia》1997,110(3):328-336
We tested the hypothesis that elevated CO2 would stimulate proportionally higher photosynthesis in the lower crown of Populus trees due to less N retranslocation, compared to tree crowns in ambient CO2. Such a response could increase belowground C allocation, particularly in trees with an indeterminate growth pattern such
as Populus tremuloides. Rooted cuttings of P. tremuloides were grown in ambient and twice ambient (elevated) CO2 and in low and high soil N availability (89 ± 7 and 333 ± 16 ng N g−1 day−1 net mineralization, respectively) for 95 days using open-top chambers and open-bottom root boxes. Elevated CO2 resulted in significantly higher maximum leaf photosynthesis (A
max) at both soil N levels. A
max was higher at high N than at low N soil in elevated, but not ambient CO2. Photosynthetic N use efficiency was higher at elevated than ambient CO2 in both soil types. Elevated CO2 resulted in proportionally higher whole leaf A in the lower three-quarters to one-half of the crown for both soil types. At elevated CO2 and high N availability, lower crown leaves had significantly lower ratios of carboxylation capacity to electron transport
capacity (V
cmax/J
max) than at ambient CO2 and/or low N availability. From the top to the bottom of the tree crowns, V
cmax/J
max increased in ambient CO2, but it decreased in elevated CO2 indicating a greater relative investment of N into light harvesting for the lower crown. Only the mid-crown leaves at both
N levels exhibited photosynthetic down regulation to elevated CO2. Stem biomass segments (consisting of three nodes and internodes) were compared to the total A
leaf for each segment. This analysis indicated that increased A
leaf at elevated CO2 did not result in a proportional increase in local stem segment mass, suggesting that C allocation to sinks other than the
local stem segment increased disproportionally. Since C allocated to roots in young Populus trees is primarily assimilated by leaves in the lower crown, the results of this study suggest a mechanism by which C allocation
to roots in young trees may increase in elevated CO2.
Received: 12 August 1996 / Accepted: 12 November 1996 相似文献
60.
The Aspergillus nidulans brlA gene is a primary regulator of development-specific gene expression during conidiation. Forced activation of brlA in vegetative cells leads to inappropriate induction of conidiophore formation and causes growth to stop. In fact, when conidia containing a nutritionally inducible brlA gene fusion are placed on inducing medium, they fail to germinate. We used this phenotype to select 174 mutants that continue growing following such forced brlA activation. Forty-six of these mutants also produced abnormal developmental structures during air-induced conidiation as expected if the mutations resulted in an altered response to BrlA (designated sbr mutants for suppressors of brlA response). The predominant mutant class identified was defective in a known developmental regulatory gene, abaA. We also identified mutants with defects in the previously characterized early acting developmental regulatory genes flbB and flbD and in four previously undescribed loci designated sbrA-D. sbrA mutants represent the second largest group and are characterized by production of conidiophore stalks that lack a normal vesicle and form branching sterigmata that rarely make spores. Because abaA expression could not be detected in sbrA mutants following brlA activation we propose that sbrA functions as a developmental modifier, participating in brlA-dependent activation of other developmental regulators. 相似文献