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71.
María Ferriol Hugo Merle Alfonso Garmendia 《Botanical journal of the Linnean Society. Linnean Society of London》2014,176(1):82-98
Survival of polyploids in nature depends on several factors, including competition from diploid relatives and increased genetic diversity. Unlike other reported Centaurea polyploid complexes, diploid Centaurea aspera and tetraploid Centaurea seridis coexist in hybrid zones with frequent triploid individuals. The polyploid origin of C. seridis, the genetic diversity and population structure of the three cytotypes, and the degree of genetic differentiation among them were analyzed in seven mixed‐ploidy zones, involving different subspecies and ecological conditions. Ploidy was determined by flow cytometry. Microsatellite data suggested an allopolyploid origin of C. seridis. In the contact zones, diploids and tetraploids were genetically differentiated. When compared with the related C. aspera, a low genetic diversity was observed in C. seridis, which is uncommon in tetraploids. Furthermore, although diploid individuals were grouped in a single widespread genetic cluster, tetraploids were grouped in two highly differentiated clusters and showed significant isolation by distance. This genetic pattern in C. seridis may be related to a minimal gene flow with diploid relatives and/or other genetic factors, such as rare polyploidization events, founder effects or an increased selfing rate. Neither taxonomic assignment at subspecies level, nor ecological conditions could explain the genetic differentiation between tetraploid clusters. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176 , 82–98. 相似文献
72.
Previous studies have described that arbuscular mycorrhizal fungi (AMF) can reduce the deleterious effect of Verticillium dahliae Kleb. on pepper growth and yield. In mycorrhizal plants, the bioprotection against soil-borne pathogens can result from the preactivation of defence responses that include some structural modifications and the accumulation of Pathogenesis-Related (PR) proteins. Our first objective was to study if V. dahliae induced defence mechanisms in roots before infected pepper developed visible symptoms of disease. The second aim was to determine if AMF induced defence-related enzymatic activities in pepper roots before or after pathogen’s attack. Results showed that the colonization of pepper roots by Glomus deserticola (Trappe, Bloss and Menge) induced the appearance of new isoforms of acidic chitinases, superoxide dismutase (SOD) and, at early stages, peroxidases. In contrast, V. dahliae neither stimulated the phenylpropanoid pathway nor elicited hydrolytic activities in infected pepper roots. Only in mycorrhizal plants, the inoculation with V. dahliae slightly increased both phenylalanine ammonia-lyase (PAL) and peroxidase activities two weeks later. Mycorrhizal-specific induction of new isoforms of acidic chitinases and SOD together with enhanced peroxidase and PAL activities 2 weeks after pathogen inoculation could be involved in the biocontrol of Verticillium-induced wilt in pepper by AMF. 相似文献
73.
J. Germán Rodríguez Piero Rouget Javier Franco Joxe Mikel Garmendia Iñigo Muxika Victoriano Valencia Ángel Borja 《Ecological Indicators》2010,10(4):891-895
The European Water Framework Directive (WFD) requires monitoring programmes, to establish a coherent and comprehensive overview of ecological and chemical water status. Recently and within this context, the use of biomarkers has been proposed for incorporation into WFD monitoring programmes. In the present study, cages have been used to transplant (ranging between 14 and 75 days) adults of the dogwhelk Nassarius reticulatus in relation to a gradient of tributyltin (TBT) pollution; this is in order to evaluate its usefulness within the WFD monitoring programmes. Only the most polluted site (close to a shipyard) shows evidence of TBT contamination effects. As such, it may be concluded that the use of caged transplants with N. reticulatus (adults) is useful only for areas of high TBT pollution. Thus, within the European WFD context, this approach is generally not useful for surveillance and operational monitoring, but has some potential in investigative monitoring. 相似文献
74.
Moure María Candela Pérez Torrado Roberto Garmendia Gabriela Vero Silvana Querol Amparo Alconada Teresa León Peláez Ángela 《International microbiology》2023,26(2):361-370
International Microbiology - Kefir is a fermented probiotic drink obtained by placing kefir granules in a suitable substrate. The kefir granules are a consortium of bacteria and yeasts embedded in... 相似文献
75.
By site-directed mutagenesis we have changed into Cys the Ser232 of the phi 29 terminal protein (TP) involved in the covalent linkage to dAMP for the initiation of replication. The mutant TP, highly purified, had about 0.7% of the priming activity of the wild-type (wt) protein p3. The linkage between the mutant protein p3 and dAMP was more labile to piperidine treatment than the serine-dAMP linkage in the wt protein p3, suggesting the presence of a different kind of linkage, Cys-dAMP. In the other three mutant TPs, residues Leu220, Ser223 and Ser226 were independently changed into Pro; the purified TP mutants had about 3%, 140% and 1% of the priming activity of the wt p3, respectively. All the mutant TP were able to interact with the phi 29 DNA polymerase and with DNA, suggesting that Leu220 and Ser226, in addition to Ser232, form part of a functional domain involved in the process of initiation of DNA replication. 相似文献
76.