ceanothus

Natural selection can drive the repeated evolution of reproductive isolation, but the genomic basis of parallel speciation remains poorly understood. We analyzed whole-genome divergence between replicate pairs of stick insect populations that are adapted to different host plants and undergoing parallel speciation. We found thousands of modest-sized genomic regions of accentuated divergence between populations, most of which are unique to individual population pairs. We also detected parallel genomic divergence across population pairs involving an excess of coding genes with specific molecular functions...

Defoliation by herbivores can reduce carbon assimilation, change plant water relations, and even shift the biotic structure of plant communities. In this study, we took advantage of a long-term deer exclosure experiment to examine the consequences of persistent deer herbivory on plant water relations and the xylem structure-function relationships in Ceanothus rigidus, a maritime chaparral shrub in coastal California. Browsed plants had thicker stems with many intertwined short distal twigs, and significantly higher sapwood-to-leaf area ratios than their non-browsed counterparts...

Soluble receptor for advanced glycation end products (sRAGE) is a secreted mammalian protein that functions as a decoy to counter-react RAGE signaling-resultant pathological conditions, and has high therapeutic potentials. Our prior studies showed that recombinant human sRAGE expressed in Chinese hamster, Ceanothus griseus, ovary (CHO) cells is modified by specific N-glycosylation, and exhibits higher bioactivity than that expressed in other host systems including insect Spodoptera frugiperda cells. Here, we show that GeneOptimizer software program-assisted, reengineered sRAGE cDNA enhances the recombinant protein expression in CHO cells...

A cloned cDNA partial copy of a soybean leghemoglobin mRNA was used to probe genomic DNA of four species of actinorhizal plants. Southern blot hybridization revealed the presence of sequences with homology to the leghemoglobin probe in DNA from Alnus glutinosa, Casuarina glauca, Ceanothus americanus and Elaeagnus pungens. The hybridization patterns of the restriction fragments revealed some fragment size conservation between the DNA of soybean and the DNA of four actinorhizal plants which are taxonomically unrelated to soybean or to each other...

The occurrence of uncultivated Frankia was evaluated in Tunisian soils by a plant-trapping assay using Coriaria myrtifolia seedlings. Despite the lack of this compatible host plant for more than two centuries, soil-borne Frankia cells were detected in one sampled soil as shown by the development of root nodules on 2-year-old seedlings. Based on glnA sequences, Tunisian trapped Frankia strains belong to the uncultivated cluster 2 strains that associate with other Coriaria species and also with Ceanothus, Datisca and Rosaceae actinorhizal species...

The recent increase in wildfire frequency in the Santa Monica Mountains (SMM) may substantially impact plant community structure. Species of Chaparral shrubs represent the dominant vegetation type in the SMM. These species can be divided into three life history types according to their response to wildfires. Nonsprouting species are completely killed by fire and reproduce by seeds that germinate in response to a fire cue, obligate sprouting species survive by resprouting from dormant buds in a root crown because their seeds are destroyed by fire, and facultative sprouting species recover after fire both by seeds and resprouts...

UNLABELLED: • PREMISE OF THE STUDY: Hybridization is thought to have played an important role in diversification of the speciose shrub genus Ceanothus; putative hybrid species have been described, and data suggest that intrinsic barriers may not exist among closely related species. However, the extent to which hybridization occurs in the wild is not known, and little is understood about how extrinsic factors such as soil chemistry may influence the process. The present research focuses on the gabbro-endemic C...

Biological nitrogen fixation (BNF) is a key ecological process that can restore nitrogen (N) lost in wildfire and shape the pace and pattern of post-fire forest recovery. To date, there is limited information on how climate and soil fertility interact to influence different pathways of BNF in early forest succession. We studied asymbiotic (forest floor and soil) and symbiotic (the shrub Ceanothus integerrimus) BNF rates across six sites in the Klamath National Forest, California, USA. We used combined gradient and experimental phosphorus (P) fertilization studies to explore cross-site variation in BNF rates and then related these rates to abiotic and biotic variables...

BACKGROUND: The combustible nature of chaparral plants has been attributed to the presence of secondary compounds such as phenolic acids, flavonoids and essential oils, among others. However, the implication of the antimicrobial properties of secondary compounds of chaparral in modulating rumen microbial metabolism has not been determined. The effects of 11 chaparral plants on rumen microbial fermentation were assessed in an in vitro batch culture fermentation fed a barley silage:barley grain-based low concentrate (LC) and high concentrate (HC) diets...

PREMISE OF THE STUDY: Ceanothus roderickii is an endangered shrub endemic to California. To investigate the population genetics of this species, including the genetic consequences of population fragmentation and hybridization, 10 microsatellite markers were developed. METHODS AND RESULTS: Using next-generation sequencing (454) data from a single C. roderickii individual, 10 microsatellite markers were developed. A group of 12 individuals representing all of the major C...

Simple models of plant response to warming climates predict vegetation moving to cooler and/or wetter locations: in mountainous regions shifting upslope. However, species-specific responses to climate change are likely to be much more complex. We re-examined a recently reported vegetation shift in the Santa Rosa Mountains, California, to better understand the mechanisms behind the reported shift of a plant distribution upslope. We focused on five elevational zones near the center of the gradient that captured many of the reported shifts and which are dominated by fire-prone chaparral...

To construct an evolutionary hypothesis for the genus Frankia, gyrB (encoding gyrase B), nifH (encoding nitrogenase reductase) and glnII (encoding glutamine synthetase II) gene sequences were considered for 38 strains. The overall clustering pattern among Frankia strains based on the three analyzed sequences varied among themselves and with the previously established 16S rRNA gene phylogeny and they did not reliably reflect clear evolution of the four discerned Frankia clusters (1, 2, 3 and 4). Based on concatenated gyrB, nifH and glnII, robust phylogenetic trees were observed with the three treeing methods (Maximum Likelihood, Parsimony and Neighbor-Joining) and supported by strong bootstrap and posterior probability values (>75%) for overall branching...

Leaf death due to freezing was examined for four, co-occurring species of chaparral shrubs from the Santa Monica Mountains of southern California, Rhus laurina (= Malosma laurina), R. ovata, Ceanothus megacarpus, and C. spinosus. Measurements were made on seedlings vs. adults for all species, and for Rhus spp. in winter vs. summer, and at a warm vs. a cold site. We used four methods to determine the temperature for 50% change in activity or cell death (LT(50)) of leaves: (1) electrical conductivity (electrolyte leakage into a bathing solution), (2) photosynthetic fluorescent capacity (Fv/Fm), (3) percentage of palisade mesophyll cells stained by fluorescein diacetate vital stain, and (4) visual score of leaf color (Munsell color chart)...

Progressive diebacks of outer canopy branchlets of Ceanothus crassifolius were repeatedly observed after rainless periods up to 9 mo in duration in the Santa Monica Mountains of southern California. Mean xylem pressures of branchlets near the end of drought were as low as -11.2 MPa (N = 22) with a mean of about 60 dead branchlets per shrub. Inoculation (N = 15) with three species of fungi previously isolated from the same population of C. crassifolius did not promote dieback, suggesting that the observed decline was not fungal induced, as had been proposed...

Separate effects of abiotic and biotic factors on the structure and dynamics of ecological communities may be recorded in growth rings of woody plants. We used Ceanothus cuneatus rigidus and Arctostaphylos pumila to tease apart the roles of fire, rain, and herbivores on the histories and community structure of four areas in a coastal mediterranean-type climate in central California with mild winters and mild summers. Ring widths of both species were related to rainfall in two of the areas; heavy deer browsing on Ceanothus overwhelmed the climate signal in the others...

We used pairs of congeneric shrub species from contrasting habitats to test for repeated evolutionary divergence in leaf-stem allometry and shoot hydraulic architecture in response to water availability. Allometric relationships and mean ratios between leaf size (individual and total area and mass per shoot) and stem cross-sectional area were compared between habitats using six species pairs representing three genera (Arctostaphylos, Baccharis, Ceanothus). We measured correlations among evolutionary changes in allometric, morphological, and physiological traits using phylogenetic independent contrasts...

Many woody plant species that depend upon fire-cued seed germination lack the ability to resprout. As the ability to resprout is widely assumed to be the ancestral condition in most plant groups, the failure to sprout is an evolutionary derived trait. Models for the evolutionary loss of sprouting assume a trade-off between seedling success and vegetative resprouting ability of adults. Such models require higher seedling success rates in nonsprouters than in sprouters. On the other hand, there seem to be few a priori reasons why a strong sprouter might not also have highly competitive post-fire seedlings...

Habitat loss is widely considered the greatest threat to biodiversity. However, habitat loss brings with it myriad other threats that exacerbate impacts to biodiversity. For instance, altered fire regime is associated with habitat loss and fragmentation with unknown consequences to biodiversity. Plant functional groups that rely on fire to complete their life cycle may be adversely affected by disruptions to the natural fire regime, particularly when coupled with population declines due to habitat loss. We used a spatially explicit stochastic population model linked with fire hazard functions to investigate the cumulative effects of habitat loss, fragmentation, and altered fire regime on the expected minimum abundance of a long-lived obligate-seeding shrub, Ceanothus greggii var...

The concepts of niche conservatism and adaptive radiation have played central roles in the study of evolution and ecological diversification. With respect to phenotypic evolution, the two processes may be seen as opposite ends of a spectrum; however, there is no straightforward method for the comparative analysis of trait evolution that will identify these contrasting scenarios. Analysis of the rate of phenotypic evolution plays an important role in this context and merits increased attention. In this article, independent contrasts are used to estimate rates of evolution for continuous traits under a Brownian motion model of evolution...

Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C...