Showing papers in "Journal of Botany in 2010"
TL;DR: Recent developments in understanding of genome size evolution in plants are reviewed, drawing attention to the higher order processes that can influence the mechanisms generating changing genome size.
Abstract: Genome sizes vary considerably across all eukaryotes and even among closely related species. The genesis and evolutionary dynamics of that variation have generated considerable interest, as have the patterns of variation themselves. Here we review recent developments in our understanding of genome size evolution in plants, drawing attention to the higher order processes that can influence the mechanisms generating changing genome size.
122 citations
TL;DR: Nonphotochemical fluorescence quenching as an indicator of energy dissipation not used in photosynthesis was shown to be increased by the effect of CuO NPs and may give a reliable methodological approach to evaluate toxicity risk of NPs in aquatic ecosystems.
Abstract: Copper oxide nanoparticles (CuO NPs), used in antifouling paints of boats, are released in the environment and can induce toxicity to aquatic organisms. In this report, we used chlorophyll a fluorescence imaging to evaluate CuO NPs toxicity in Lemna gibba. This approach allowed to evaluate the differential effect of CuO NPs on photosynthesis of whole L. gibba plants. Exposure to 0.1 to 0.4 g/L CuO NPs during 48h induced strong inhibition of photosynthetic processes resulting in a decrease of plant growth. By using fluorescence imaging, different photosynthetic parameters were evaluated simultaneously in microplate conditions. Imaging of
78 citations
TL;DR: The results suggest pollen is not a good candidate for inferring the genome size of ancient species because its biology is different than other cells which have been shown to be strongly related to genome size, such as guard cells.
Abstract: Here we test whether genome size is a predictor of pollen size. If it were, inferences of ancient genome size would be possible using the abundant paleo-palynolgical record. We performed regression analyses across 464 species of pollen width and genome size. We found a significant positive trend. However, regression analysis using phylogentically independent contrasts did not support the correlated evolution of these traits. Instead, a large split between angiosperms and gymnosperms for both pollen width and genome size was revealed. Sister taxa were not more likely to show a positive contrast when compared to deeper nodes. However, significantly more congeneric species had a positive trend than expected by chance. These results may reflect the strong selection pressure for pollen to be small. Also, because pollen grains are not metabolically active when measured, their biology is different than other cells which have been shown to be strongly related to genome size, such as guard cells. Our findings contrast with previously published research. It was our hope that pollen size could be used as a proxy for inferring the genome size of ancient species. However, our results suggest pollen is not a good candidate for such endeavors.
75 citations
TL;DR: This paper compares various genomic characters between monocots and the remaining angiosperms to discern just how distinctive monocot genomes are, and it is apparent that different monOCot orders follow distinctive modes of genome size and chromosome evolution.
Abstract: Monocot genomic diversity includes striking variation at many levels. This paper compares various genomic characters (e.g., range of chromosome numbers and ploidy levels, occurrence of endopolyploidy, GC content, chromosome packaging and organization, genome size) between monocots and the remaining angiosperms to discern just how distinctive monocot genomes are. One of the most notable features of monocots is their wide range and diversity of genome sizes, including the species with the largest genome so far reported in plants. This genomic character is analysed in greater detail, within a phylogenetic context. By surveying available genome size and chromosome data it is apparent that different monocot orders follow distinctive modes of genome size and chromosome evolution. Further insights into genome size-evolution and dynamics were obtained using statistical modelling approaches to reconstruct the ancestral genome size at key nodes across the monocot phylogenetic tree. Such approaches reveal that while the ancestral genome size of all monocots was small (1C=1.9 pg), there have been several major increases and decreases during monocot evolution. In addition, notable increases in the rates of genome size-evolution were found in Asparagales and Poales compared with other monocot lineages.
73 citations
TL;DR: It is demonstrated that both of the values for the largest genome size so far for the monocots of Fritillaria assyriaca and for the eudicots of Viscum cruciatum need to be corrected.
Abstract: This paper presents the largest genome sizes reported so far for angiosperms: for the monocots Trillium hagae ( Melanthiaceae) 2 C = 2 6 4 . 9 pg and for the eudicots Viscum album (Santalaceae) with 2 C = 2 0 5 . 8 pg. They were found during ongoing measurements of nuclear DNA content in more than 4000 accessions. Moreover, it is demonstrated that both of the values for the largest genome size so far for the monocots of Fritillaria assyriaca and for the eudicots of Viscum cruciatum need to be corrected.
64 citations
TL;DR: This review focuses on the current knowledge of the mechanisms that control the maintenance and alteration of the genome of angiosperm mitochondria.
Abstract: The angiosperm mitochondrial genome is the largest and least gene-dense among the eukaryotes, because its intergenic regions are expanded. There seems to be no functional constraint on the size of the intergenic regions; angiosperms maintain the large mitochondrial genome size by a currently unknown mechanism. After a brief description of the angiosperm mitochondrial genome, this review focuses on our current knowledge of the mechanisms that control the maintenance and alteration of the genome. In both processes, the control of homologous recombination is crucial in terms of site and frequency. The copy numbers of various types of mitochondrial DNA molecules may also be controlled, especially during transmission of the mitochondrial genome from one generation to the next. An important characteristic of angiosperm mitochondria is that they contain polypeptides that are translated from open reading frames created as byproducts of genome alteration and that are generally nonfunctional. Such polypeptides have potential to evolve into functional ones responsible for mitochondrially encoded traits such as cytoplasmic male sterility or may be remnants of the former functional polypeptides.
62 citations
TL;DR: Despite optimizing the concentration and composition of antioxidants in nuclei-isolation buffer for each species, the effect of cytosolic compounds present in the leaves could not be avoided entirely and the DNA content was estimated for the first time.
Abstract: The presence of some secondary metabolites in the cell cytosol can cause a stoichiometric error in the flow cytometric estimation of nuclear DNA content. There is no fully reliable method to completely eliminate the effect of these compounds on nuclei fluorescence, and therefore using plant organs/parts free of staining inhibitors is recommended. Eleven species of Rosaceae with high concentrations of propidium-iodide-staining inhibitors were studied to check the possibility of using seeds instead of leaves for genome size estimation. Despite optimizing the concentration and composition of antioxidants in nuclei-isolation buffer for each species, the effect of cytosolic compounds present in the leaves could not be avoided entirely. None of the seeds of the studied species contained inhibitors, and they produced histograms of good quality. The genome size of the studied species ranged from 1.15 to 3.17 pg/2C; for 10 species the DNA content was estimated for the first time.
53 citations
TL;DR: It is confirmed, on a different methodological basis than previously, that along the pollution gradient, species with high C- and Cx-values are increasingly underrepresented, lending support to the “large genome constraint hypothesis”, predicting that plants with large genomes are at a disadvantage under all aspects of evolution, ecology, and phenotype.
Abstract: The Death Valley at Žerjav in northern Slovenia exhibits a gradient of heavy metal pollution in the soil with severe consequences for species richness and composition along this gradient. Recently, a progressive loss of large-genome species in parallel with increasing concentrations of heavy metals has been shown. Here, we have measured the genome size of a near-complete sample of these species with flow cytometry and analysed the correlation of heavy metal pollution with the C- and Cx-values assigned to the test plots. The method of probability analysis was a hypergeometric distribution method. We confirm, on a different methodological basis than previously, that along the pollution gradient, species with high C- and Cx-values are increasingly underrepresented. This lends support to the “large genome constraint hypothesis”, predicting that plants with large genomes are at a disadvantage under all aspects of evolution, ecology, and phenotype, because junk DNA imposes a load to the organism.
51 citations
TL;DR: The genome downsizing, occurring during or immediately after the formation of these polyploids, provides the physical basis for their cytological diploidization, that is, diploids-like meiotic behavior.
Abstract: Nuclear DNA amount, determined by the flow cytometry method, in diploids, natural and synthetic allopolyploids, and natural and synthetic autopolyploids of the tribe Triticeae (Poaceae) is reviewed here and discussed. In contrast to the very small and nonsignificant variation in nuclear DNA amount that was found at the intraspecific level, the variation at the interspecific level is very large. Evidently changes in genome size are either the cause or the result of speciation. Typical autopolyploids had the expected additive DNA amount of their diploid parents, whereas natural and synthetic cytologically diploidized autopolyploids and natural and synthetic allopolyploids had significantly less DNA than the sum of their parents. Thus, genome downsizing, occurring during or immediately after the formation of these polyploids, provides the physical basis for their cytological diploidization, that is, diploid-like meiotic behavior. Possible mechanisms that are involved in genome downsizing and the biological significance of this phenomenon are discussed.
46 citations
TL;DR: Ethyl acetate extracts of all selected plants exhibited relatively low MICs and could be therefore described as strong antibacterial.
Abstract: Our aim was to determine the antimicrobial activity of three selected plants ( Rosmarinus officinalis, Origanum majorana, and Trigonella foenum-graecum) against Extended Spectrum Beta Lactamase (ESBL)—producing Escherichia coli and Klebsiella pneumoniae—
and to identify the specific plant fraction responsible for the antimicrobial activity. The plants were extracted with ethanol to yield the crude extract which was further subfractionated by different solvents to obtain the petroleum ether, the dichloromethane, the ethyl acetate, and the aqueous fractions. The Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) were determined using broth microdilution. The MICs ranged between 1.25 and 80 𝜇 g / 𝜇 l . The majority of these microorganisms were inhibited by 80 and 40 𝜇 g / 𝜇 l of the crude extracts. The petroleum ether fraction of Origanum majorana significantly inhibited 94% of the tested strains. Ethyl acetate extracts of all selected plants exhibited relatively low MICs and could be therefore described as strong antibacterial.
38 citations
TL;DR: It is found that the rates of genome size evolution for woody lineages were consistently an order of magnitude slower than those of herbaceous lineages, suggesting that growth form constrains genome size Evolution, not through consequences associated with the phenotype, but instead through the influence of life history attributes on the tempo of evolution.
Abstract: Broadly sampled phylogenies have uncovered extreme deviations from a molecular clock with the rates of molecular substitution varying dramatically within/among lineages. While growth form, a proxy for life history, is strongly correlated with molecular rate heterogeneity, its influence on trait evolution has yet to be examined. Here, we explore genome size evolution in relation to growth form by combining recent advances in large-scale phylogeny construction with model-based phylogenetic comparative methods. We construct phylogenies for Monocotyledonae (monocots) and Fabaceae (legumes), including all species with genome size information, and assess whether rates of genome size evolution depend on growth form. We found that the rates of genome size evolution for woody lineages were consistently an order of magnitude slower than those of herbaceous lineages. Our findings also suggest that growth form constrains genome size evolution, not through consequences associated with the phenotype, but instead through the influence of life history attributes on the tempo of evolution. Consequences associated with life history now extend to genomic evolution and may shed light on the frequently observed threshold effect of genome size variation on higher phenotypic traits.
TL;DR: A significant negative exponential relationship was observed between GS and RMGR, which represents a significant consequence of GS expansion in plants and may partly explain why genome sizes tend to be small in eudicots.
Abstract: Variation in genome size (GS) has been linked to several facets of the plant phenotype. Recently it was shown that GS is significantly correlated with cell size and the duration of the cell cycle. Here we test the hypothesis that GS might also be a predictor of apical root meristem growth rate (RMGR). We studied eight species of eudicots with varying GS using time-lapse microscopic image analysis. A significant negative exponential relationship was observed between GS and RMGR. Our results show significantly decreased RMGR for large genome species. This relationship represents a significant consequence of GS expansion in plants and may partly explain why genome sizes tend to be small in eudicots. Interestingly, parasitic plants, which do not rely on root growth as much, often have large genomes.
TL;DR: The phylogenetic analysis of the ITS data set has produced results that generally support the most-recent infrageneric classification, and all are unanimous in placing Chosenia arbutifolia within the genus Salix.
Abstract: The genus Salix has proven a fertile taxon for a host of evolutionary and ecological studies, yet much work remains in the development of a definitive phylogenetic context for those studies. We performed phylogenetic analyses, using both maximum likelihood and maximum parsimony techniques, of chloroplast-encoded matK and nuclear-encoded ribosomal DNA (rDNA) gene sequences, gathered from specimens deemed representative of the existing subgeneric classification, with the objective of identifying and elaborating the phylogenetic relationships within Salix. Comparisons between the two phylogenetic hypotheses indicate a high degree of polyphyly in the matK-based phylogeny. This we attribute to the effects of hybridization, introgression, and lineage sorting. Comparisons with previous molecule-based phylogenetic hypotheses indicate a fair degree of congruence and all are unanimous in placing Chosenia arbutifolia within the genus Salix. The phylogenetic analysis of our ITS data set has produced results that generally support the most-recent infrageneric classification.
TL;DR: Monoploid genome sizes were found to be statistically constant among ploidy levels, in contrast to the different taxonomic positions of the di- and tetraploids and also contrasts with the frequent occurrence of genome downsizing in polyploids.
Abstract: ost woodland morphologically and cytogenetically. The population consisted of diploid B. nana (38%), tetraploid B. pubescens (55%), and triploid hybrids (7%). Genome size was measured from 12 plants, using Feulgen DNA image densitometry (FDM) on spring leaf buds and flow cytometry (FCM) with dormant winter twigs. The use of winter twigs for FCM is novel. The average 1C-values for diploid, triploid, and tetraploid plants were 448, 666, and 882 Mbp, respectively. Monoploid genome sizes were found to be statistically constant among ploidy levels. This stability is in contrast to the different taxonomic positions of the di- and tetraploids and also contrasts with the frequent occurrence of genome downsizing in polyploids.
TL;DR: The investigation confirmed that all four tetraploids belong to the same AB-genome group; however A. agadiriana occupies distinct position among others, and the results suggest that at least one of them could be related to A. damascena.
Abstract: Tetraploid oat species Avena abyssinica, A. vaviloviana, A. barbata, and A. agadiriana were studied using C-banding technique, in situ hybridization with the 45S and 5S rDNA probes, and RAPD analysis in comparison with the diploid species carrying different types of the A-genome (A. wiestii, As; A. longiglumis, Al; A. canariensis, Ac; A. damascena, Ad, A. prostrata, Ap). The investigation confirmed that all four tetraploids belong to the same AB-genome group; however A. agadiriana occupies distinct position among others. The C-banding, FISH, and RAPD analyses showed that Avena abyssinica, A. vaviloviana, and A. barbata are very similar; most probably they originated from a common tetraploid ancestor as a result of minor translocations and alterations of C-banding polymorphism system. AB-genome species are closely related with the A-genome diploids, and an As-genome species may be regarded as the most probable donor of their A-genome. Although their second diploid progenitor has not been identified, it seems unlikely that it belongs to the As-genome group. The exact diploid progenitors of A. agadiriana have not been determined; however our results suggest that at least one of them could be related to A. damascena.
TL;DR: The data indicated that species found far from the centre of origin in Asia clustered into separate sections and series and possessed higher DNA content, and a significantly decreased 1Cx DNA content was observed with the increase in ploidy for six species.
Abstract: The nuclear DNA content for 256 different accessions belonging to 26 primary Malus species and 20 species hybrids was estimated by flow cytometry using propidium iodide. Diploids ranged from 1.245 ( M. tschonoskii) to 1.653 pg per 2C nucleus ( M. florentina). As our study covered complete phylogenetic and geographic representation, preliminary conclusions between nuclear DNA content and geographical and taxonomic features could be drawn. The data indicated that species found far from the centre of origin in Asia clustered into separate sections and series and possessed higher DNA content. These are M. trilobata and M. florentina the only two species existing in South-East Europe on one hand; M. ioensis and 3x and 4x species M. × heterophylla, M. × platycarpa, M. glaucescens, M. angustifolia, M. lancifolia and M. coronaria—in East and Central North America on the other hand. A significantly decreased 1Cx DNA content was observed with the increase in ploidy for six species.
TL;DR: Variation between species for sHsp expression (induction temperatures, accumulation levels, and the duration of expression) coupled with the costs of Hsp synthesis, may contribute to differences in the abundance and distribution of plants across environmental gradients.
Abstract: Small heat shock protein (sHsp) responses were studied for two evergreen perennial shrubs in the northern California chaparral; one common on warm, south-facing slopes (Ceanothus cuneatus), and the other on cooler, north-facing slopes (Prunus ilicifolia). Small Hsp expression was induced experimentally for field collected leaves. Leaf collections were made where the species co-occur. Small Hsp expression was quantified using two antibodies, one specific to a chloroplast 22 kD sHsp and another that detects a broad range of sHsps. Differences between chloroplast sHsp accumulation, which protects thermally labile proteins in PSII, and the general sHsp response were examined. The species from the cooler microclimate, Prunus, had a lower induction temperature and accumulated greater levels of sHsps at low temperatures. Both Prunus and Ceanothus reached peak sHsp expression at . The species from the warmer microclimate, Ceanothus, had greater sHsp expression at higher temperatures. Chloroplast sHsp expression generally tracked sHsp expression in Ceanothus, but in Prunus general Hsps were elevated before chloroplast sHsps. Variation between species for sHsp expression (induction temperatures, accumulation levels, and the duration of expression) coupled with the costs of Hsp synthesis, may contribute to differences in the abundance and distribution of plants across environmental gradients.
TL;DR: As bryophytes form a paraphyletic grade leading to the tracheophytes, understanding the prevalence and role of endopolyploidy in this group is important.
Abstract: Endopolyploidy occurs when DNA replication is not followed by mitotic nuclear division, resulting in tissues or organisms with nuclei of varying ploidy levels. Endopolyploidy appears to be a common phenomenon in plants, though the prevalence of endopolyploidy has not been determined in bryophytes (including mosses and liverworts). Forty moss species and six liverwort species were analyzed for the degree of endopolyploidy using flow cytometry. Nuclei were extracted in LB01 buffer and stained with propidium iodide. Of the forty moss species, all exhibited endopolyploid nuclei (mean cycle value =0.65±0.038) except for the Sphagnum mosses (mean cycle value ). None of the liverwort species had endopolyploid nuclei (mean cycle value ). As bryophytes form a paraphyletic grade leading to the tracheophytes, understanding the prevalence and role of endopolyploidy in this group is important.
TL;DR: A gene pool that is moderately diverse and sexually active and has significant but small genetic differences among populations and little correspondence between geographic and genetic distance is explored, consistent with a model of multiple introductions followed by high rates of gene exchange between cities and regions.
Abstract: Ailanthus altissima is an invasive tree from Asia. It now occurs in most US states, and although primarily an urban weed, it has become a problem in forested areas especially in the eastern states. Little is known about its genetic structure. We explore its naturalized gene pool from 28 populations, mostly of the eastern US where infestations are especially severe. Five microsatellite markers were used to examine presumed neutral genetic variation. Results show a gene pool that is moderately diverse and sexually active and has significant but small genetic differences among populations and little correspondence between geographic and genetic distance. These findings are consistent with a model of multiple introductions followed by high rates of gene exchange between cities and regions. We propose movement along road and railway systems as the chief mode of range expansion.
TL;DR: Two genes, ACT and EF1, are selected as the optimal housekeeping genes to evaluate transgenic Eucommia ulmoides Oliver root lines overexpressing IPPI or FPPS1 genes, which are involved in isoprenoid biosynthesis.
Abstract: In order to select appropriate housekeeping genes for accurate calibration of experimental variations in real-time (RT-) PCR results in transgene expression analysis, particularly with respect to the influence of transgene on stability of endogenous housekeeping gene expression in transgenic plants, we outline a reliable strategy to identify the optimal housekeeping genes from a set of candidates by combining statistical analyses of their (RT-) PCR amplification efficiency, gene expression stability, and transgene influences. We used the strategy to select two genes, ACT and EF1, from 10 candidate housekeeping genes, as the optimal housekeeping genes to evaluate transgenic Eucommia ulmoides Oliver root lines overexpressing IPPI or FPPS1 genes, which are involved in isoprenoid biosynthesis.
TL;DR: It is concluded that careful consideration should be made toward design parameters to limit result biases and ultimately facilitate comparison of findings between studies.
Abstract: In the objective of testing the design of pot-growth experiments, we conducted two greenhouse studies of a “dwarf” sunflower cultivar and an arbuscular mycorrhizal (AM) fungus to determine how pot size and inoculum distribution affect plant growth and AM symbiosis. As predicted, large-potted plants developed a greater overall biomass and root colonization than small-potted ones which we attributed to the larger “rootable” volume. Furthermore, plants grown in a band of high density inoculum substrate showed a higher prevalence of fungal vesicles (sites of lipid storage) indicating a more advanced level of root colonization compared to those grown in a dispersed inoculum substrate; this likely being due to the higher frequency of interaction between roots and fungal propagules. In a second experiment, large-potted AM plants showed a greater tolerance to water deficit than non-AM control plants; however, this mycorrhizal effect was not detected among small-potted plants. We conclude that careful consideration should be made toward design parameters to limit result biases and ultimately facilitate comparison of findings between studies.
TL;DR: This work is the first large genome size study devoted to the Valerianaceae, showing a range of DNA amounts from ”pg (Valerianella turgida) to pg ( Valeriana officinalis).
Abstract: The purpose of this study is to provide a new focus to contribute, from the perspective of genomic evolution, towards a better understanding of the Valerianaceae evolutionary history. Chromosome numbers were determined by Feulgen staining in 24 populations of 18 species (first count for Valerianella multidentata, –16), and DNA contents were assessed by flow cytometry in 74 populations of 35 species (first assessments in all taxa but Centranthus ruber). A molecular phylogeny based on the trnL-trnF and including 41 new sequences was established, with the first DNA sequence for Centranthus nevadensis, Valeriana rotundifolia, V. saxatilis, Valerianella multidentata, and V. turgida. This work is the first large genome size study devoted to the Valerianaceae, showing a range of DNA amounts from pg (Valerianella turgida) to pg (Valeriana officinalis). At the family level, changes in basic chromosome number and genome size coincide with or precede major shifts in the evolutionary history of the group, such as those concerning stamen number and floral symmetry.
TL;DR: The AM symbiosis is considered to be a key component of ecosystem function involved in buffering plant growth conditions due to the processes of metal biosorption and hyphal alkalinisation which could contribute in enhancing the soil's resiliency.
Abstract: An in vivo compartmental pot greenhouse experiment involving “dwarf” sunflower and an arbuscular mycorrhizal (AM) fungus was designed to assess the contribution of non-AM roots (rhizosphere), AM roots and extraradical hyphae (mycorrhizosphere), or strictly extraradical hyphae (hyphosphere) on plant growth, plant metal uptake, and soil parameters using the micronutrient zinc (Zn) as a typical metal contaminant. We observed that, at high soil-Zn concentrations, the mycorrhizosphere treatments had lower Zn concentrations (especially in shoots and flowers) and a lower incidence of leaf chlorosis than the rhizosphere treatments. These phytoprotective effects are believed to be related to AM-induced biosorption processes that reduce soil metal bioavailability to delay the onset of plant metal toxicity. We also observed that the presence of extraradical hyphae causes a slight alkalinisation of the proximal soil environment whereas roots tended to acidify it, this having significant consequences toward metal bioavailability. Altogether, the AM symbiosis is considered to be a key component of ecosystem function involved in buffering plant growth conditions due to the processes of metal biosorption and hyphal alkalinisation which could contribute in enhancing the soil's resiliency.
TL;DR: The data on the phyA polymorphism are summarized with attention to the applied experimental approach and may explain, at least partially, the nature of the uniqueness of thephyA action.
Abstract: In higher plants, photoreceptor phytochrome (phy)—photoisomerizing biliprotein working as a light-driven molecular switch—is represented by a small family of phytochrome gene products with phyA and phyB as major species. phyA is unique among other phytochromes mediating photoresponse modes specific only for this pigment (far-red light induced) and also photoresponses characteristic of phyB and other minor phys (red light induced). In our group, in vivo fluorescence investigations of phytochrome were initiated and two native phyA pools—posttranslationally modified PHYA gene products designated phyA′ and phyA″—were detected in dicots and monocots. They differ by spectroscopic and photochemical parameters, by abundance and distribution in etiolated plant tissues, by light stability, and other phenomenological characteristics, and, most importantly, by their functional properties. This may explain, at least partially, the nature of the uniqueness of the phyA action. In this paper, the data on the phyA polymorphism are summarized with attention to the applied experimental approach.
TL;DR: Contrary to the increase in genome size suggested earlier for Hepatica, a significant (6%–14%) loss of nuclear DNA in the natural allopolyploids was found.
Abstract: Genome size (C-value) was applied anew to investigate the relationships within the genus Hepatica (Ranunculaceae). More than 50 samples representing all species (except H. falconeri), from wild and cultivated material, were investigated. Species of Hepatica turn out to be diploid (2𝑛=14), tetraploid (2𝑛=28 ), and a possible pentaploid. The somatic nuclear DNA contents (2C-value), as measured by flow cytometry with propidium iodide, were shown to range from 33 to 80 pg. The Asiatic and American species, often considered subspecies of H. nobilis, could be clearly distinguished from European H. nobilis. DNA content confirmed the close relationships in the Asiatic species, and these are here considered as subspecies of H. asiatica. Parents for the allotetraploid species could be suggested based on their nuclear DNA content. Contrary to the increase in genome size suggested earlier for Hepatica, a significant (6%–14%) loss of nuclear DNA in the natural allopolyploids was found.
TL;DR: A combined UPGMA dendrogram was generated which revealed that different genotypes exhibited their affinity according to their geographical distribution, and tree topology suggests the existence of two distinct groups of the genotypes.
Abstract: Astragalus rhizanthus with three infraspecific taxa (i.e., A. rhizanthus ssp. rhizanthus var. rhizanthus, A. rhizanthus ssp. rhizanthus var. pindreensis, and A. rhizanthus ssp. candolleanus) is widely scattered in the Himalaya from Jammu and Kashmir to Uttarakhand provinces in India. Among them, A. rhizanthus ssp. rhizanthus var. rhizanthus exhibits enormous morphological diversity throughout its range of distribution. An assessment of genetic diversity studies was undertaken to understand the level and pattern of diversity, using Inter simple sequence repeats (ISSR), Random amplified polymorphic DNA (RAPD) and Directed amplification of minisatellite DNA (DAMD) profiles. Fifteen ISSR, 18 RAPD and 6 DAMD primers were used to unravel the diversity among 20 genotypes collected from the known localities in the Indian Himalaya. A total of 242 bands from ISSR, 352 from RAPD and 142 from DAMD were obtained with an average of 92.23% polymorphism in the species. Pair-wise genetic similarity for the cumulative data was determined using Jaccard's similarity coefficient which varied from 0.19 to 0.84. A combined UPGMA dendrogram was generated which revealed that different genotypes exhibited their affinity according to their geographical distribution. Tree topology suggests the existence of two distinct groups of the genotypes. Gene diversity
TL;DR: In the authors' growth experiments, Arabidopsis had high seed sterility at higher temperature, which might be one reason for the rarity of A. thaliana in Middle Asia.
Abstract: Contrary to literature data Arabidopsis thaliana was rarely observed in Middle Asia during a collection trip in 2001. Instead, three other Brassicaceae species were frequently found at places where A. thaliana was expected. To reveal reasons for this frequency pattern, we studied chromosome numbers, genome sizes, phylogenetic relationships, developmental rates, and reproductive success of A. thaliana, Olimarabidopsis pumila, Arabis montbretiana, and Arabis auriculata from Uzbekistan in two temperature treatments. There are little but partially significant differences between phenotypes. All studied species have very small genomes. The 1Cx-values of different genotypes within the sampled species are correlated with altitude. Developmental rates are also correlated with 1Cx-values. In our growth experiments, Arabidopsis had high seed sterility at higher temperature, which might be one reason for the rarity of A. thaliana in Middle Asia.
TL;DR: This improved and reproducible technique was shown to be rapid, inexpensive, and simple for nuclear extraction from a single root tip, and can be adapted for other plants and purposes.
Abstract: Root meristems have increasingly been target of cell cycle studies by flow cytometric DNA content quantification. Moreover, roots can be an alternative source of nuclear suspension when leaves become unfeasible and for chromosome analysis and sorting. In the present paper, a protocol for intact nuclei isolation from a single root meristem was developed. This proceeding was based on excision of the meristematic region using a prototypical slide, followed by short enzymatic digestion and mechanical isolation of nuclei during homogenization with a hand mixer. Such parameters were optimized for reaching better results. Satisfactory nuclei amounts were extracted and analyzed by flow cytometry, producing histograms with reduced background noise and CVs between 3.2 and 4.1%. This improved and reproducible technique was shown to be rapid, inexpensive, and simple for nuclear extraction from a single root tip, and can be adapted for other plants and purposes.
TL;DR: Quantitative evaluation, statistical analyses, and MALDI-TOF MS characterization of the resolved spots in green and etiolated samples of C. cardunculus enabled us to identify 46 out of 60 spots, containing 21 spots included conserved Viridiplantae domains.
Abstract: Etiolation of vegetables is a complex phenomenon implying qualitative and quantitative protein changes. The 2-DE protein profile of green and etiolated fleshy stalk samples has shown great differences in the 4–7 pH and 10 to 250 kDa mass range. Currently, a shortage of Cynara DNA or protein sequences has required the use of de novo sequencing and BLAST similarity searches for protein identification. Highlighted herein is an application of proteomics to the identification of proteins, which in a great part matched those from the Viridiplantae order. Quantitative evaluation, statistical analyses, and MALDI-TOF MS characterization of the resolved spots in green and etiolated samples of C. cardunculus enabled us to identify 46 out of 60 spots, containing 21 spots included conserved Viridiplantae domains.
The etiolation process is discussed in light of the identification of some proteins involved in specific biochemical and metabolic pathways.