Unravelling wild carrot differentiation in Europe: preliminary data on a candidate gene approach

Carrot is an outcrossing species and levels of gene flow between populations, and even between wild and domesticated relatives, are expected to be high. Cases of natural hybridization and introgression of crops and wild relatives have been reported. Have these events diluted any putative habitat-adapted genotypes? In other words, can we still find a correlation between wild carrot genotypes and regional/local environment? We have chosen to start addressing this question using a member of the alternative oxidase (AOX) gene family. AOX genes seem to be linked to all kinds of abiotic and biotic stress reactions. Wild carrots were sampled in an environmental gradient across Western Europe. This gradient included sampling points with more deviating conditions, such as Sierra de Guadarrama or the central Pyrenees and the French Massif Central. Phylogenetic reconstruction on this molecular marker is to be combined with geographic, climatic, and ecological evidence. So far, the preliminary results suggest the existence of a biogeographical barrier at the Pyrenees, and higher gene diversity than initially expected. From an applied point of view, diversity of functional traits is much more relevant than species diversity. Gene transfer from wild to cultivated plants has contributed to the evolution of crop species. Providing that deterioration of genetic resources and biodiversity loss have not been drastic, gene transfer from wild plants has the potential to further contribute to a (targeted) improvement of cultivars.info:eu-repo/semantics/publishedVersio

Isolation of alternative oxidase (AOX) genes of Olea europaea L.

Alternative oxidase (AOX) is recently suggested to be a potential candidate as functional marker for efficient cell reprogramming under stress (Arnholdt-Schmitt et al., 2006a). The presented work is part of a Marie Curie Chair project, that was established to investigate the potential role of the multigene AOX to assist breeding on efficient rooting of olive shoot cuttings (Arnholdt-Schmitt et al. 2006b). Plant mito-chondrial AOX is a small nuclear-encoded multigene family consisting of the two subfamilies AOX1 and AOX2. The intron-exon structure of AOX has been well characterized in several species, revealing a large degree of conservation. Here we report for the first time about the isolation of AOX multigene se-quences of olive (Olea europaea L.). The genes were isolated from a portuguese clone of the landrace ‘Galega vulgar’

Induction of somatic embryogenesis as an example of stress-related plant reactions

In this review, we address the role of stress as one of the principal causes for a cell or tissue to change its pre-existing somatic program, reprogramming itself to express the embryogenic pathway. The focus of this paper is the effect of different stress conditions on the induction phase of plant somatic embryogenesis, as well as the development of embryogenic competence as a result of the applied stresses. We also present a variety of data that link plant somatic embryogenesis, DNA methylation and oxidative stress response

Daucus carota L. – An old model for cell reprogramming gains new importance through a novel expansion pattern of alternative oxidase (AOX) genes

The paper highlights Daucus carota L. as an ideal model to complement plant stress research on Arabidopsis thaliana L. Recently, alternative oxidase (AOX) is discussed as functional marker candidate for cell reprogramming upon stress. Carrot is the most studied species for cell reprogramming and our current research reveals that it is the only one that has expanded both AOX sub-family genes. We point to recently published, but not discussed results on conserved differences in the vicinity of the most active functional site of AOX1 and AOX2, which indicate the importance of studying AOX sequence polymorphism, structure and functionality. Thus, stress-inducible experimental systems of D. carota are especially appropriate to bring research on stress tolerance a significant step forward

Functional marker development from AOX genes requires deep phenotyping and individualized diagnosis

The development of new ‘deep phenotyping’ techniques for functional markers (FM) development on alternative oxidase (AOX) gene sequences are expected to greatly increase the efficiency of association studies between the candidate FM sequences and the desired phenotype. However, it is critical to perform these studies in the appropriate target tissue/cell at the correct time point. AOX genes, due to their diversity and with differential methylation marks, are likely also subjected to such interplay between sequence and regulatory mechanisms. Polymorphisms in coding sequences may directly affect protein function, but expression regulatory switches are more abundant in non-coding regions. Transgenic technology continues to contribute to crop improvement programme, if efforts are directed more towards FM-assisted plant breeding. Hence, AOX can be put into best use if a dual approach involving genetic transformation and conventional plant breeding go hand in hand

Genetic diversity in natural populations of Jacaranda decurrens Cham. determined using RAPD and AFLP markers

Jacaranda decurrens (Bignoniaceae) is an endemic species of the Cerrado with validated antitumoral activity. The genetic diversity of six populations of J. decurrens located in the State of São Paulo was determined in this study by using molecular markers for randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP). Following optimization of the amplification reaction, 10 selected primers generated 78 reproducible RAPD fragments that were mostly (69.2%) polymorphic. Two hundred and five reproducible AFLP fragments were generated by using four selected primer combinations; 46.3% of these fragments were polymorphic, indicating a considerable level of genetic diversity. Analysis of molecular variance (AMOVA) using these two groups of markers indicated that variability was strongly structured amongst populations. The unweighted pair group method with arithmatic mean (UPGMA) and Pearson's correlation coefficient (RAPD -0.16, p = 0.2082; AFLP 0.37, p = 0.1006) between genetic matrices and geographic distances suggested that the population structure followed an island model in which a single population of infinite size gave rise to the current populations of J. decurrens, independently of their spatial position. The results of this study indicate that RAPD and AFLP markers were similarly efficient in measuring the genetic variability amongst natural populations of J. decurrens. These data may be useful for developing strategies for the preservation of this medicinal species in the Cerrado