How to Avoid Sex

Grossniklaus, Ueli; Nogler, Gian A.; Dijk, Peter J. van

doi:10.1105/tpc.13.7.1491

Cited by 88 publications

(20 citation statements)

References 21 publications

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“…Direct identification of the genes and genomic elements comprised on these apomixis linked loci however has proven difficult. This is because they are commonly recombination-suppressed and flanked by repetitive regions, interfering with sequencing approaches and map-based cloning [10,[35][36][37][38][39][40][41]. In several species studied, apomixis linked loci represent chromosomal regions that largely diverged from corresponding sexual loci.…”

Section: Genetic Loci Linked To Apomixis Typically Represent Hemizygomentioning

confidence: 99%

Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation

Schmidt

2020

Genes

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In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.

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Section: Genetic Loci Linked To Apomixis Typically Represent Hemizygomentioning

confidence: 99%

Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation

Schmidt

2020

Genes

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“…An early theory regarding genetic control of apomixis proposed that the trait is regulated by “a delicate gene balance” (Muntzing 1940) of recessive genes and that this balance might be disturbed after crosses. Currently, basic inheritance is usually thought to depend on a single master regulatory gene or a few dominant key genes, which allow a megaspore mother cell or a somatic nucellar cell to form an embryo sac without meiotic reduction and an embryo to develop from an unreduced egg cell without fertilization (Asker and Jerling 1992; Koltunow et al 1995; Savidan 2000; Grossniklaus et al 2001b). Once apomictic genes initiate embryo development and the initial cell forms and divides, the genes controlling embryo cell formation and patterning are most likely the same as those required for sexual embryo development.…”

Section: Searching For Genes Controlling Apomixis In Natural Apomictsmentioning

confidence: 99%

Apomixis in plant reproduction: a novel perspective on an old dilemma

2013

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Seed is one of the key factors of crop productivity. Therefore, a comprehension of the mechanisms underlying seed formation in cultivated plants is crucial for the quantitative and qualitative progress of agricultural production. In angiosperms, two pathways of reproduction through seed exist: sexual or amphimictic, and asexual or apomictic; the former is largely exploited by seed companies for breeding new varieties, whereas the latter is receiving continuously increasing attention from both scientific and industrial sectors in basic research projects. If apomixis is engineered into sexual crops in a controlled manner, its impact on agriculture will be broad and profound. In fact, apomixis will allow clonal seed production and thus enable efficient and consistent yields of high-quality seeds, fruits, and vegetables at lower costs. The development of apomixis technology is expected to have a revolutionary impact on agricultural and food production by reducing cost and breeding time, and avoiding the complications that are typical of sexual reproduction (e.g., incompatibility barriers) and vegetative propagation (e.g., viral transfer). However, the development of apomixis technology in agriculture requires a deeper knowledge of the mechanisms that regulate reproductive development in plants. This knowledge is a necessary prerequisite to understanding the genetic control of the apomictic process and its deviations from the sexual process. Our molecular understanding of apomixis will be greatly advanced when genes that are specifically or differentially expressed during embryo and embryo sac formation are discovered. In our review, we report the main findings on this subject by examining two approaches: i) analysis of the apomictic process in natural apomictic species to search for genes controlling apomixis and ii) analysis of gene mutations resembling apomixis or its components in species that normally reproduce sexually. In fact, our opinion is that a novel perspective on this old dilemma pertaining to the molecular control of apomixis can emerge from a cross-check among candidate genes in natural apomicts and a high-throughput analysis of sexual mutants.

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“…DNA methylation is defined as the addiction, catalyzed by several methyltransferases, of a methyl group to the 5' C of a cytosine residue in the DNA sequence, which is associated with silencing of transposons, imprinting, and silencing of both transgenes and endogenous genes (e.g. Grossniklaus et al, 2001;Zilberman et al, 2007;Jones, 2012). In plants, DNA methylation is the best understood epigenetic mechanism and several studies intimate it exhibits a transgenerational inheritance (e.g.…”

Section: Introductionmentioning

confidence: 99%

Effects of Temperature Treatments on Cytosine-Methylation Profiles of Diploid and Autotetraploid Plants of the Alpine Species Ranunculus kuepferi (Ranunculaceae)

et al. 2020

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The exposure to environmental stress can trigger epigenetic variation, which may have several evolutionary consequences. Polyploidy seems to affect the DNA methylation profiles. Nevertheless, it abides unclear whether temperature stress can induce methylations changes in different cytotypes and to what extent a treatment shift is translated to an epigenetic response. A suitable model system for studying these questions is Ranunculus kuepferi, an alpine perennial herb. Diploid and autotetraploid individuals of R. kuepferi were exposed to cold (+7°C day/+2°C night; frost treatment −1°C cold shocks for 3 nights per week) and warm (+15°day/+10°C night) conditions in climate growth chambers for two consecutive flowering periods and shifted from one condition to the other after the first flowering period. Methylation-sensitive amplified fragment-length polymorphism markers were applied for both years, to track down possible alterations induced by the stress treatments. Patterns of methylation suggested that cytotypes differed significantly in their profiles, independent from year of treatment. Likewise, the treatment shift had an impact on both cytotypes, resulting in significantly less epiloci, regardless the shift's direction. The AMOVAs revealed higher variation within than among treatments in diploids. In tetraploids, internally-methylated loci had a higher variation among than within treatments, as a response to temperature's change in both directions, and support the hypothesis of temperature stress affecting the epigenetic variation. Results suggest that the temperature-sensitivity of DNA methylation patterns shows a highly dynamic phenotypic plasticity in R. kuepferi, as both cytotypes responded to temperature shifts. Furthermore, ploidy level, even without effects of hybridization, has an important effect on epigenetic background variation, which may be correlated with the DNA methylation dynamics during cold acclimation.

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How to Avoid Sex

Cited by 88 publications

References 21 publications

Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation

Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation

Apomixis in plant reproduction: a novel perspective on an old dilemma

Effects of Temperature Treatments on Cytosine-Methylation Profiles of Diploid and Autotetraploid Plants of the Alpine Species Ranunculus kuepferi (Ranunculaceae)

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