Anthocyanins are secondary metabolites found in higher plants that contribute to the colors of flowers and fruits. In apples (Malus domestica Borkh.), several steps of the anthocyanin pathway are coordinately regulated, suggesting control by common transcription factors. A gene encoding an R2R3 MYB transcription factor was isolated from apple (cv Cripps' Pink) and designated MdMYB1. Analysis of the deduced amino acid sequence suggests that this gene encodes an ortholog of anthocyanin regulators in other plants. The expression of MdMYB1 in both Arabidopsis (Arabidopsis thaliana) plants and cultured grape cells induced the ectopic synthesis of anthocyanin. In the grape (Vitis vinifera) cells MdMYB1 stimulated transcription from the promoters of two apple genes encoding anthocyanin biosynthetic enzymes. In ripening apple fruit the transcription of MdMYB1 was correlated with anthocyanin synthesis in red skin sectors of fruit. When dark-grown fruit were exposed to sunlight, MdMYB1 transcript levels increased over several days, correlating with anthocyanin synthesis in the skin. MdMYB1 gene transcripts were more abundant in red skin apple cultivars compared to non-red skin cultivars. Several polymorphisms were identified in the promoter of MdMYB1. A derived cleaved amplified polymorphic sequence marker designed to one of these polymorphisms segregated with the inheritance of skin color in progeny from a cross of an unnamed red skin selection (a sibling of Cripps' Pink) and the non-red skin cultivar Golden Delicious. We conclude that MdMYB1 coordinately regulates genes in the anthocyanin pathway and the expression level of this regulator is the genetic basis for apple skin color.

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Light-induced expression of a MYB gene regulates anthocyanin biosynthesis in red apples.

In an age of accelerating biodiversity loss, this timely and critical volume summarizes recent advances in biodiversity-ecosystem functioning research and explores the economics of biodiversity and ecosystem services. The book starts by summarizing the development of the basic science and provides a meta-analysis that quantitatively tests several biodiversity and ecosystem functioning hypotheses. It then describes the natural science foundations of biodiversity and ecosystem functioning research including: quantifying functional diversity, the development of the field into a predictive science, the effects of stability and complexity, methods to quantify mechanisms by which diversity affects functioning, the importance of trophic structure, microbial ecology, and spatial dynamics. Finally, the book takes research on biodiversity and ecosystem functioning further than it has ever gone into the human dimension, describing the most pressing environmental challenges that face humanity and the effects of diversity on: climate change mitigation, restoration of degraded habitats, managed ecosystems, pollination, disease, and biological invasions.However, what makes this volume truly unique are the chapters that consider the economic perspective. These include a synthesis of the economics of ecosystem services and biodiversity, and the options open to policy-makers to address the failure of markets to account for the loss of ecosystem services; an examination of the challenges of valuing ecosystem services and, hence, to understanding the human consequences of decisions that neglect these services; and an examination of the ways in which economists are currently incorporating biodiversity and ecosystem functioning research into decision models for the conservation and management of biodiversity. A final section describes new advances in ecoinformatics that will help transform this field into a globally predictive science, and summarizes the advancements and future directions of the field. The ultimate conclusion is that biodiversity is an essential element of any strategy for sustainable development.

Biodiversity, Ecosystem Functioning, and Human Wellbeing: An Ecological and Economic Perspective

In mammals, cadmium is widely considered as a non-genotoxic carcinogen acting through a methylation-dependent epigenetic mechanism. Here, the effects of Cd treatment on the DNA methylation patten are examined together with its effect on chromatin reconfiguration in Posidonia oceanica. DNA methylation level and pattern were analysed in actively growing organs, under short- (6 h) and long- (2 d or 4 d) term and low (10 mM) and high (50 mM) doses of Cd, through a Methylation-Sensitive Amplification Polymorphism technique and an immunocytological approach, respectively. The expression of one member of the CHROMOMETHYLASE (CMT) family, a DNA methyltransferase, was also assessed by qRT-PCR. Nuclear chromatin ultrastructure was investigated by transmission electron microscopy. Cd treatment induced a DNA hypermethylation, as well as an up-regulation of CMT, indicating that de novo methylation did indeed occur. Moreover, a high dose of Cd led to a progressive heterochromatinization of interphase nuclei and apoptotic figures were also observed after long-term treatment. The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase. Such changes are linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin. Overall, the data show an epigenetic basis to the mechanism underlying Cd toxicity in plants.

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In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning

Dormancy in temperate fruit trees in a global warming context: A review

The intention of this review is to discuss floral initiation of horticultural trees. Floral initiation is best understood for herbaceous species, especially at the molecular level, so a brief overview of the control of floral initiation of Arabidopsis (Arabidopsis thaliana (L.) Heynh.) precedes the discussion of trees. Four major pathways to flowering have been characterized in Arabidopsis, including environmental induction through photoperiod and temperature, autonomous floral initiation, and regulation by gibberellins. Tropical trees are generally induced to flower through environmental cues, whereas floral initiation of temperate deciduous trees is often autonomous. In the tropical evergreen tree mango, Mangifera indica L., cool temperature is the only factor known to induce flowering, but does not ensure floral initiation will occur because there are important interactions with vegetative growth. The temperate deciduous tree apple, Malus domestica Borkh., flowers autonomously, with floral initiation dependent on aspects of vegetative development in the growing season before anthesis, although with respect to the floral initiation of trees in general: the effect of the environment, interactions with vegetative growth, the roles of plant growth regulators and carbohydrates, and recent advances in molecular biology, are discussed.

/pdf/regulation-of-floral-initiation-in-horticultural-trees-59ru41w9yz.pdf

Regulation of floral initiation in horticultural trees

Identification of candidate genes mediating apple fruit-cracking resistance following the application of gibberellic acids 4 + 7 and the cytokinin 6-benzyladenine.

SUMMARYA large proportion of the honey bees from colonies placed in apple orchards collect pollen from competing flora. For four years we tested for a genetic component that would account for preferences for pollen from apple bloom. In the first two years we tested various genetic strains of bees and found significant differences among them in the proportion of apple pollen that they collected. In the final year we found that colonies that were progenies of colonies with high preference for apple pollen in the previous year (‘High strain’) tended to collect a higher proportion of apple pollen compared to colonies from a ‘Low strain.’ The genetic component for apple pollen preference that is evident from this study attests to the possibility of breeding a honey bee strain with high apple pollination effectiveness even under competition conditions.

Honey bee (Apis mellifera) strains differ in apple (Malus domestica) pollen foraging preference

SummaryJapanese plum (Prunus salicina Lindl.) belongs to the Rosaceae family, which carries the S-RNase-mediated gametophytic self-incompatibility system, which prevents self-fertilisation, and thus promotes out-crossing. The plum cultivar ‘Black Diamond’® has become, one of the most important cultivars in Israel in the last decade, yet its yield is low in comparison with its known potential. Honeybees (Apis mellifera) are the most important pollinators for plums and several studies have demonstrated an apparent relationship between the number of honeybees and the size of the fruit crop. Therefore, in this study, we focussed on improving bee management in a ‘Black Diamond’ orchard. In four consecutive years of experiments, we examined the effects of increasing the density of bee colonies, and of making multiple introductions of colonies, on honeybee activity and on their effectiveness as pollinators of ‘Black Diamond’. We showed that four separate introductions, each of 0.625 colonies ha–1, every 2 – 3 d ...

Multiple introduction of honeybee colonies increases cross-pollination, fruit-set and yield of ‘Black Diamond’ Japanese plum (Prunus salicina Lindl.)

S-RNase based S-genotyping of Japanese plum (Prunus salicina Lindl.) and its implication on the assortment of cultivar-couples in the orchard

Japanese plum (Prunus salicinaLindl.), a species of theRosaceaefamily, carries the S-RNase-mediated gametophytic self-incompatibility system. Self-incompatibility ismanifestediftheS-haplotypeofthepolleniscarriedalsobythepollinatedflower.Thus, for fertilization to occur, the cultivars have to be genetically compatible. The haplotype is conferred by an S-locus, which contains the style-specific expressed S-RNase and the pollen-specific expressed F-box genes (SFB). Since both the S-RNase and the SFB genes are multiallelic and are characteristic of each of the S-haplotypes, they are ideal markers for molecular S-typing. In this work, seven SFBs, from eight japanese plum cultivars, were cloned and sequenced. Five of the alleles were published recently and two SFB g and SFB k are new. The physical linkage of SFB b and SFB c to their adjacent S-RNase was determined; it is 544 base pairs (bp) and 404 bp for the S b and S c loci, respectively.

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Raphael A. Stern

Papers

Identification of candidate genes mediating apple fruit-cracking resistance following the application of gibberellic acids 4 + 7 and the cytokinin 6-benzyladenine.

Honey bee (Apis mellifera) strains differ in apple (Malus domestica) pollen foraging preference

Multiple introduction of honeybee colonies increases cross-pollination, fruit-set and yield of ‘Black Diamond’ Japanese plum (Prunus salicina Lindl.)

S-RNase based S-genotyping of Japanese plum (Prunus salicina Lindl.) and its implication on the assortment of cultivar-couples in the orchard

SFBs of Japanese Plum (Prunus salicina): Cloning Seven Alleles and Determining Their Linkage to the S-RNase Gene