In recent years, few classes of natural products have received as much attention as phenolics and polyphenols. This special issue of Molecules, “Phenolics and Polyphenolics”, is a remarkable confirmation of this trend. Several aspects related to phenolics chemistry, comprising the several classes, will be discussed. In addition, the increasing interest in phenolics’ biological activities is covered, and several works addressing this matter are referred.

/pdf/phenolics-from-chemistry-to-biology-4awj5bh0im.pdf

Phenolics: From Chemistry to Biology

Anthocyanins, synthesized via the flavonoid pathway, are a class of crucial phenolic compounds which are fundamentally responsible for the red color of grapes and wines. As the most important natural colorants in grapes and their products, anthocyanins are also widely studied for their numerous beneficial effects on human health. In recent years, the biosynthetic pathway of anthocyanins in grapes has been thoroughly investigated. Their intracellular transportation and accumulation have also been further clarified. Additionally, the genetic mechanism regulating their biosynthesis and the phytohormone influences on them are better understood. Furthermore, due to their importance in the quality of wine grapes, the effects of the environmental factors and viticulture practices on anthocyanin accumulation are being investigated increasingly. The present paper summarizes both the basic information and the most recent advances in the study of the anthocyanin biosynthesis in red grapes, emphasizing their gene structure, the transcriptional factors and the diverse exterior regulation factors.

http://disciplinas.stoa.usp.br/pluginfile.php/91135/mod_resource/content/1/molecules15%282010%299057.pdf

Biosynthesis of Anthocyanins and Their Regulation in Colored Grapes

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.

/pdf/in-posidonia-oceanica-cadmium-induces-changes-in-dna-3cu7uj83mr.pdf

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

Introduction. Ecologically Meaningful Germination Studies. Types of Seed Dormancy. Germination Ecology of Seeds with Nondeep Physiological Dormancy. Germination Ecology of Seeds with Morphophysiological Dormancy. Germination Ecology of Seeds with Physical Dormancy. Germination Ecology of Seeds in the Persistent Seed Bank. Causes of Within-Species Variations in Seed Dormancy and Germination Characteristics. A Geographical Perspective on Germination Ecology: Tropical and Subtropical Zones. A Geographical Perspective on Germination Ecology: Temperate and Arctic Zones. Germination Ecology of Plants with Specialized Life Cycles and/or Habitats. Biogeographical and Evolutionary Aspects of Seed Dormancy. Subject Index.

A Definitive Book on Seed Ecology@@@Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination

Flavonoids and their glycosides, including anthocyanins

Although coevolution is acknowledged to occur in nature, coevolutionary patterns in symbioses not involving species-to-species relationships are poorly understood. Mycorrhizal plants are thought to be too generalist to coevolve with their symbiotic fungi; yet some plants, including some orchids, exhibit strikingly narrow mycorrhizal specificity. Here, we assess the evolutionary history of mycorrhizal specificity in the lady's slipper orchid genus, Cypripedium. We sampled 90 populations of 15 taxa across three continents, using DNA methods to identify fungal symbionts and quantify mycorrhizal specificity. We assessed phylogenetic relationships among sampled Cypripedium taxa, onto which we mapped mycorrhizal specificity. Cypripedium taxa associated almost exclusively with fungi within family Tulasnellaceae. Ancestral specificity appears to have been narrow, followed by a broadening after the divergence of C. debile. Specificity then narrowed, resulting in strikingly narrow specificity in most of the taxa in this study, with no taxon rewidening to the same extant as basal members of the genus. Sympatric taxa generally associated with different sets of fungi, and most clades of Cypripedium-mycorrhizal fungi were found throughout much of the northern hemisphere, suggesting that these evolutionary patterns in specificity are not the result of biogeographic lack of opportunity to associate with potential partners. Mycorrhizal specificity in genus Cypripedium appears to be an evolvable trait, and associations with particular fungi are phylogenetically conserved.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1558-5646.2007.00112.x

The evolutionary history of mycorrhizal specificity among lady's slipper orchids.

In vitro asymbiotic germination of immature seed and formation of protocorm by Cephalanthera falcata (Orchidaceae)

Cypripedium macranthos is a wild orchid that is becoming endangered. Efficient methods for its propagation from seed, which is indispensable for conservation, production and breeding, have not been reported. The effects of sodium and calcium hypochlorite, pre-chilling and cytokinins on the germination of seeds of Cypripedium macranthos Swartz were examined. The duration of treatment with a solution of hypochlorite prior to sowing was one of the critical factors that affected germination. Approximately 70% of seeds that had been treated with either a solution of NaClO that contained 0.5% available chlorine for 60 min or with one of Ca(ClO)2 with 3.2% available chlorine for 7 h, germinated after 3 months of culture at 20°C, subsequent to 2 months chilling at 4°C. Chilling seeds at 4°C prior to culture at 20°C was another factor that stimulated germination. Even chilling for 2 weeks had a promotive effect on germination, and chilling for 2 months enhanced it most effectively: the frequency of germination was 67% after 3 months of culture at 20°C. However, the promotive effects of chilling on germination were reduced by holding seeds at 20°C for 3 and 6 weeks prior to chilling treatment. Germination of 58-70% was achieved by the addition of 1 µM cytokinin to the medium, while the frequency was only 17% in cytokinin-free medium. We report a reproducible and efficient method for enhancing seed germination of C. macranthos, which involves treatment with hypochlorite prior to sowing, and the combination of chilling at 4°C prior to germination and exposure to a cytokinin.

Stimulatory effects of sodium and calcium hypochlorite, pre‐chilling and cytokinins on the germination of Cypripedium macranthos seed in vitro

Premise of the study Mycoheterotrophic plants, which completely depend upon mycorrhizal fungi for their nutrient supply, have unusual associations with fungal partners. The processes involved in shifts in fungal associations during cladogenesis of plant partners from autotrophy to mycoheterotrophy have not been demonstrated using a robust phylogenetic framework. Methods Consequences of a mycorrhizal shift were examined in Cymbidium (Orchidaceae) using achlorophyllous and sister chlorophyllous species. Fungal associates of the two achlorophyllous mycoheterotrophs (C. macrorhizon and C. aberrans), their close relatives, the chlorophyllous mixotrophs (C. goeringii and C. lancifolium) and an outgroup, the chlorophyllous autotroph C. dayanum, were identified by internal transcribed spacers of the nuclear ribosomal DNA sequences. Key results Molecular identification of mycorrhizal fungi revealed: (1) the outgroup autotroph is predominantly dependent on saprobic Tulasnellaceae, (2) the mixotrophs associate with the Tulasnellaceae and ectomycorrhizal groups including the Sebacinales, Russulaceae, Thelephoraceae and Clavulinaceae, and (3) the two mycoheterotrophs are mostly specialized with ectomycorrhizal Sebacinales. Conclusion Fungal partners in Cymbidium have shifted from saprobic to ectomycorrhizal fungi via a phase of coexistence of both nutritional types of fungi. These three phases correspond to the evolution from autotrophy to mycoheterotrophy via mixotrophy in Cymbidium. We demonstrate that shifts in mycorrhizal fungi correlate with the evolution of nutritional modes in plants. Furthermore, gradual shifts in fungal partners through a phase of coexistence of different types of mycobionts may play a crucial role in the evolution of mycoheterotrophic plants.

https://bsapubs.onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.1100464

Shifts in mycorrhizal fungi during the evolution of autotrophy to mycoheterotrophy in Cymbidium (Orchidaceae).

Morphogenic calli were obtained efficiently from ab initio cultures of isolated microspores in eggplant. Initial culture of freshly isolated microspores in sucrose-free medium at high temperature (35°C) for 3 d was a prerequisite for callus induction. The microspores were re-cultured in modified NLN medium containing 2% sucrose and phytohormones (NAA 0.5 mg l(-1), BA 0.5 mg l(-1)) in the dark. After 4 weeks of re-culture, small calli derived from microspores were transferred to MS medium containing 4 mg l(-1) zeatin and 0.2 mg l(-1) IAA for shoot regeneration. The ploidy of 12 randomly selected regenerants was assessed by chromosome counts in root tips. Only one of the regenerants was haploid, 7 were diploid, 3 were triploid and one was tetraploid. The diploids set seeds after self-pollination and showed no segregation for morphological traits in the progeny, suggesting that they were spontaneously doubled haploids.

Kazumitsu Miyoshi

Papers

The evolutionary history of mycorrhizal specificity among lady's slipper orchids.

In vitro asymbiotic germination of immature seed and formation of protocorm by Cephalanthera falcata (Orchidaceae)

Stimulatory effects of sodium and calcium hypochlorite, pre‐chilling and cytokinins on the germination of Cypripedium macranthos seed in vitro

Shifts in mycorrhizal fungi during the evolution of autotrophy to mycoheterotrophy in Cymbidium (Orchidaceae).

Callus induction and plantlet formation through culture of isolated microspores of eggplant (Solanum melongena L.)