Article

Seasonal cardenolide production and Dop5betar gene expression in natural populations of Digitalis obscura.

Departamento de Biología Vegetal, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot (Valencia), Spain.
Phytochemistry (impact factor: 3.35). 08/2004; 65(13):1869-78. DOI:10.1016/j.phytochem.2004.05.004 pp.1869-78
Source: PubMed

ABSTRACT Productivity variations and seasonal fluctuations of cardenolides have been studied in 10 natural populations of Digitalis obscura distributed in three bioclimatic belts. Main cardenolides in D. obscura plants are those of the series A and such predominance (ca. 80-85%) over the series B metabolites is independent of the population studied or the degree of maturity of the leaves. Primary glycosides represent ca. 50-60% of total cardenolides; this percentage did not vary among populations or with the leaf age but increased in summer and decreased in winter. A correlation analysis between plant biomass and cardenolide content showed a positive relationship of these parameters, which, according to the bioclimatic distribution of the populations, suggests that certain environmental conditions may cause marked decreases in plant biomass together with a reduction in productivity. Cardenolide contents changed in the timecourse of the four seasons as a multiple response to distinct plant and/or environmental factors. The lowest production was recorded in May, followed by a fast cardenolide accumulation in summer, a decreasing phase in autumn, and a stationary phase in winter. We also analysed the seasonal expression of the gene encoding the progesterone 5beta-reductase, enzyme producing the required 5beta-configured intermediaries of cardenolides. A fragment of the isolated partial genomic sequence was used as a probe for Northern analysis to study the seasonal gene expression in selected populations. The expression pattern showed increasing levels from February to July and a further reduction in autumn, although harmful climatic conditions seems to induce overexpression of this gene.

0 0
 · 
0 Bookmarks
 · 
34 Views
  • Source
    Article: The Vein Patterning 1 (VEP1) gene family laterally spread through an ecological network.
    Rosa Tarrío, Francisco J Ayala, Francisco Rodríguez-Trelles
    [show abstract] [hide abstract]
    ABSTRACT: Lateral gene transfer (LGT) is a major evolutionary mechanism in prokaryotes. Knowledge about LGT--particularly, multicellular--eukaryotes has only recently started to accumulate. A widespread assumption sees the gene as the unit of LGT, largely because little is yet known about how LGT chances are affected by structural/functional features at the subgenic level. Here we trace the evolutionary trajectory of VEin Patterning 1, a novel gene family known to be essential for plant development and defense. At the subgenic level VEP1 encodes a dinucleotide-binding Rossmann-fold domain, in common with members of the short-chain dehydrogenase/reductase (SDR) protein family. We found: i) VEP1 likely originated in an aerobic, mesophilic and chemoorganotrophic α-proteobacterium, and was laterally propagated through nets of ecological interactions, including multiple LGTs between phylogenetically distant green plant/fungi-associated bacteria, and five independent LGTs to eukaryotes. Of these latest five transfers, three are ancient LGTs, implicating an ancestral fungus, the last common ancestor of land plants and an ancestral trebouxiophyte green alga, and two are recent LGTs to modern embryophytes. ii) VEP1's rampant LGT behavior was enabled by the robustness and broad utility of the dinucleotide-binding Rossmann-fold, which provided a platform for the evolution of two unprecedented departures from the canonical SDR catalytic triad. iii) The fate of VEP1 in eukaryotes has been different in different lineages, being ubiquitous and highly conserved in land plants, whereas fungi underwent multiple losses. And iv) VEP1-harboring bacteria include non-phytopathogenic and phytopathogenic symbionts which are non-randomly distributed with respect to the type of harbored VEP1 gene. Our findings suggest that VEP1 may have been instrumental for the evolutionary transition of green plants to land, and point to a LGT-mediated 'Trojan Horse' mechanism for the evolution of bacterial pathogenesis against plants. VEP1 may serve as tool for revealing microbial interactions in plant/fungi-associated environments.
    PLoS ONE 01/2011; 6(7):e22279. · 4.09 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

10 natural populations
 
bioclimatic belts
 
bioclimatic distribution
 
D. obscura plants
 
Digitalis obscura
 
distinct plant
 
expression pattern
 
fast cardenolide accumulation
 
induce overexpression
 
isolated partial genomic sequence
 
leaf age
 
lowest production
 
Main cardenolides
 
plant biomass
 
Productivity variations
 
progesterone 5beta-reductase
 
required 5beta-configured intermediaries
 
seasonal fluctuations
 
seasonal gene expression
 
series B metabolites