Variable methylation and differential replication of genomic DNA in cultured carrot root expiants during growth induction as influenced by hormonal treatments

Arnholdt‐Schmitt, Birgit; Holzapfel, B.; Schillinger, A.; Neumann, K.–H.

doi:10.1007/bf02190613

Cited by 21 publications

(6 citation statements)

References 22 publications

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“…Thirty‐six hours after inoculation marks the termination of a first cell cycle round, which is initiated synchronously in some cells of the explant. Six days marks ending of the lag phase and 14 days relates to the linear phase of exponential growth (r = 0.813) (see in Gartenbach‐Scharrer et al 1990, Arnholdt‐Schmitt et al 1991, Arnholdt‐Schmitt 1995, 1999).…”

Section: Methodsmentioning

confidence: 99%

Differential expression and co‐regulation of carrot AOX genes (Daucus carota)

Campos

Cardoso

Linke

et al. 2009

Physiologia Plantarum

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Alternative oxidase (AOX) is a mitochondrial protein encoded by the nuclear genome. In higher plants AOX genes form a small multigene family mostly consisting of the two subfamilies AOX1 and AOX2. Daucus carota L. is characterized by a unique extension pattern of AOX genes. Different from other plant species studied so far it contains two genes in both subfamilies. Therefore, carrot was recently highlighted as an important model in AOX stress research to understand the evolutionary importance of both AOX subfamilies. Here we report on the expression patterns of DcAOX1a, DcAOX1b and DcAOX2a and DcAOX2b. Our results demonstrate that all of the four carrot AOX genes are expressed. Differential expression was observed in organs, tissues and during de novo induction of secondary root phloem explants to growth and development. DcAOX1a and DcAOX2a indicated a differential transcript accumulation but a similar co-expression pattern. The genes of each carrot AOX sub-family revealed a differential regulation and responsiveness. DcAOX2a indicated high inducibility in contrast to DcAOX2b, which generally revealed low transcript abundance and rather weak responses. In search for withingene sequence differences between both genes as a potential reason for the differential expression patterns, the structural organization of the two genes was compared. DcAOX2a and DcAOX2b showed high sequence similarity in their open reading frames (ORFs). However, length variability was observed in the N-terminal exon1 region. The predicted cleavage site of the mitochondrial targeting sequence in this locus is untypical small for both genes and consists of 35 amino acids for DcAOX2a and of 21 amino acids for DcAOX2b. The importance of structural gene organization and the relevancy of within-gene sequence variations are discussed. Our results strengthen the value of carrot as a model plant for future studies on the importance of AOX sub family evolution.

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Section: Methodsmentioning

confidence: 99%

Differential expression and co‐regulation of carrot AOX genes (Daucus carota)

Campos

Cardoso

Linke

et al. 2009

Physiologia Plantarum

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“…EQUAL LENGTH SEX CHROMOSOMES I predict that most environmentally and hormonally induced sex changes in flowering plants and vertebrates occur via demethylation and these methylation changes are heritable (LoSchiavo et al ., 1989;Arnholdt-Schmitt et al ., 1991;Dorazi, Chesnel & Dournan, 1995;Demeulemeester, Van Stallen & De Proft, 1999;Murphy & Jirtle, 2000;Tatra et al ., 2000). Recent work indicates that sex hormones determine sex via heritable changes in methylation patterns (McLachlan, 2001).…”

Section: S Ex Change Can Be Induced In Lineages Withmentioning

confidence: 99%

Evolution of dioecy and sex chromosomes via methylation driving Muller's ratchet

Gorelick

2003

Biological Journal of the Linnean Society

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Why are there two sexes in certain species, instead of one hermaphroditic sex? Why are Y chromosomes shorter than X chromosomes, but only in certain lineages? I propose that differences between sexes are initially determined by differential methylation in nuclear DNA between females and males, driving Muller's ratchet. Methylation of promoters suppresses transcription, including loci coding for gamete production, thereby converting hermaphroditic individuals into females or males. Differential methylation of sex chromosomes suppresses recombination and increases mutation rate, thereby geometrically increasing the speed of Muller's ratchet. Higher mutability of methylated nucleotides plus loss of sex-determining function of previously methylated nucleotides provides selective pressure to excise these loci, resulting in shorter Y or W chromosomes. Derived lineages usually have more methylation than do ancestral ones, and hence have relatively shorter sex chromosomes. Methylation canalizes dioecy and degeneration of sex chromosomes. Latter stages of sex chromosome evolution may have occurred via other mechanisms, for example sexually antagonistic genes or chromosomal rearrangements. A few aberrant derived lineages lost most methylation, and their sex determination and sex chromosomes may have evolved via other means. Differential methylation provides a mechanism for early evolution of dioecy in anisogamous sexual diploid eukaryotes and of sex chromosomes in metazoans.

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“…After a lag phase of approximately 7 days, exponential callus growth starts and intensive cell division takes place. At day 14, calli grow in the linear phase of exponential growth .…”

Section: Methodsmentioning

confidence: 99%

Calorespirometry as a tool for studying temperature response in carrot (Daucus carota L.)

Nogales

Muñoz-Sanhueza

Hansen

et al. 2013

Engineering in Life Sciences

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Calorespirometric measurements of metabolic heat rates and CO2 emission rates of respiring tissues as functions of temperature enable rapid determination of the temperatures that plants are adapted to without growing them in different environmental temperatures. However, the correct choice of target material for measurements that enable prediction of growth temperature responses is crucial, and needs to be identified in a species‐ and trait‐specific manner. In this study, different carrot materials were tested: a primary culture system proposed as an in vitro test system for carrot yield potential, taproots of young plants, and the root meristem of actively growing plants during secondary root growth. The central root meristem is the most suitable for studying temperature response by calorespirometry for genotype comparison. Calorespirometric methods for predicting genotype‐specific temperature responses of crop plant cultivars can be used to predict productivity in environments with differing temperature conditions.

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Variable methylation and differential replication of genomic DNA in cultured carrot root expiants during growth induction as influenced by hormonal treatments

Cited by 21 publications

References 22 publications

Differential expression and co‐regulation of carrot AOX genes (Daucus carota)

Differential expression and co‐regulation of carrot AOX genes (Daucus carota)

Evolution of dioecy and sex chromosomes via methylation driving Muller's ratchet

Calorespirometry as a tool for studying temperature response in carrot (Daucus carota L.)

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