SciCombinator

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Concept: Solanaceae

169

Modulation of the malate content of tomato (Solanum lycopersicum) fruit by altering the expression of mitochondrially localized enzymes of the tricarboxylic acid cycle resulted in enhanced transitory starch accumulation and subsequent effects on postharvest fruit physiology. In this study, we assessed whether such a manipulation would similarly affect starch biosynthesis in an organ that displays a linear, as opposed to a transient, kinetic of starch accumulation. For this purpose, we used RNA interference to down-regulate the expression of fumarase in potato (Solanum tuberosum) under the control of the tuber-specific B33 promoter. Despite displaying similar reductions in both fumarase activity and malate content as observed in tomato fruit expressing the same construct, the resultant transformants were neither characterized by an increased flux to, or accumulation of, starch, nor by alteration in yield parameters. Since the effect in tomato was mechanistically linked to derepression of the reaction catalyzed by ADP-glucose pyrophosphorylase, we evaluated whether the lack of effect on starch biosynthesis was due to differences in enzymatic properties of the enzyme from potato and tomato or rather due to differential subcellular compartmentation of reductant in the different organs. The results are discussed in the context both of current models of metabolic compartmentation and engineering.

Concepts: Metabolism, Adenosine triphosphate, Enzyme, Starch, Tomato, Solanaceae, Solanum, Potato

167

Carotenoids represent some of the most important secondary metabolites in the human diet, and tomato (Solanum lycopersicum) is a rich source of these health promoting compounds. In this work, a novel and fruit-related regulator of pigment accumulation in tomato has been identified by Artificial Neural Network Inference Analysis (ANN) and its function validated in transgenic plants. A tomato-fruit gene-regulatory network was generated using ANN and transcription-factor gene-expression profiles (Tfs) derived from fruits sampled at various points during development and ripening. One of the Tfs with a sequence related to an Arabidopsis PSEUDO RESPONSE REGULATOR 2-LIKE gene (APRR2-Like) was up-regulated at the breaker stage in wild type tomato fruits and, when over expressed in transgenic lines, increased plastid number, area and pigment content; enhancing the levels of chlorophyll in immature unripe fruits and carotenoids in red ripe fruits. Analysis of the transcriptome of transgenic lines over expressing the tomato APPR2-Like gene revealed up-regulation of several ripening-related genes in the over-expression lines providing a link between expression of this tomato gene and the ripening process. A putative orthologue of the tomato APPR2-Like gene in sweet pepper was associated with pigment accumulation in fruit tissues. We conclude that the function of this gene is conserved across taxa and that it encodes a protein that has an important role in ripening.

Concepts: Gene expression, Fruit, Tomato, Solanaceae, Vegetable, Eggplant, Ethylene, Ripening

37

The nightshade family Solanaceae holds exceptional economic and cultural importance. The early diversification of Solanaceae is thought to have occurred in South America during its separation from Gondwana, but the family’s sparse fossil record provides few insights. We report 52.2-million-year-old lantern fruits from terminal-Gondwanan Patagonia, featuring highly inflated, five-lobed calyces, as a newly identified species of the derived, diverse New World genus Physalis (e.g., groundcherries and tomatillos). The fossils are considerably older than corresponding molecular divergence dates and demonstrate an ancient history for the inflated calyx syndrome. The derived position of these early Eocene fossils shows that Solanaceae were well diversified long before final Gondwanan breakup.

Concepts: Tomato, Solanaceae, Eggplant, Charles Darwin, Dinosaur, Eocene, Cambrian, Tomatillo

31

Atropa belladonna is a poisonous plant that can cause anticholinergic effects when ingested. Roots, leaves, and fruits of the plant contain the alkaloids atropine, hyoscyamine, and scopolamine, which can lead to an anticholinergic toxidrome; however, not all characteristics of the toxidrome are necessarily present in each case of poisoning. We present an infant who suffered serious seizures after ingestion of a homeopathic agent containing A. belladonna. The 20-day-old infant arrived at the emergency department with fever and generalized seizures for 30 minutes, 2 hours after ingesting the correct dose of a homeopathic medication agent used for infantile colic. The patient was treated with intravenous benzodiazepines and antibiotics after a full sepsis work up; all the laboratory results were normal and the fever resolved after several hours. The infant recovered fully with normal neurological function and a normal electroencephalogram. This infant probably manifested what is known as the central anticholinergic syndrome. We discuss his presentation and review of the literature on this topic.

Concepts: Medicine, Poison, Solanaceae, Anticholinergic, Atropine, Hyoscyamine, Physostigmine, Atropa belladonna

29

Potato (Solanum tuberosum L.) originates from the Andes and evolved short-day-dependent tuber formation as a vegetative propagation strategy. Here we describe the identification of a central regulator underlying a major-effect quantitative trait locus for plant maturity and initiation of tuber development. We show that this gene belongs to the family of DOF (DNA-binding with one finger) transcription factors and regulates tuberization and plant life cycle length, by acting as a mediator between the circadian clock and the StSP6A mobile tuberization signal. We also show that natural allelic variants evade post-translational light regulation, allowing cultivation outside the geographical centre of origin of potato. Potato is a member of the Solanaceae family and is one of the world’s most important food crops. This annual plant originates from the Andean regions of South America. Potato develops tubers from underground stems called stolons. Its equatorial origin makes potato essentially short-day dependent for tuberization and potato will not make tubers in the long-day conditions of spring and summer in the northern latitudes. When introduced in temperate zones, wild material will form tubers in the course of the autumnal shortening of day-length. Thus, one of the first selected traits in potato leading to a European potato type is likely to have been long-day acclimation for tuberization. Potato breeders can exploit the naturally occurring variation in tuberization onset and life cycle length, allowing varietal breeding for different latitudes, harvest times and markets.

Concepts: Genetics, Solanaceae, Potato, Plant stem, Tuber, Plant reproduction, Andes, Rhizome

27

α-Tomatine is an antifungal glycoalkaloid that provides basal defense to tomato (Solanum lycopersicum). However, tomato pathogens overcome this basal defense barrier by the secretion of tomatinases that degrade α-tomatine into the less fungitoxic compounds β-tomatine and tomatidine. Although pathogenic on tomato, it has been reported that the biotrophic fungus Cladosporium fulvum is unable to detoxify α-tomatine. Here, we present a functional analysis of the glycosyl hydrolase (GH10), CfTom1, which is orthologous to fungal tomatinases. We show that C. fulvum hydrolyzes α-tomatine into tomatidine in vitro and during the infection of tomato, which is fully attributed to the activity of CfTom1, as shown by the heterologous expression of this enzyme in tomato. Accordingly, ∆cftom1 mutants of C. fulvum are more sensitive to α-tomatine and are less virulent than the wild-type fungus on tomato. Although α-tomatine is thought to be localized in the vacuole, we show that it is also present in the apoplast, where it is hydrolyzed by CfTom1 on infection. The accumulation of tomatidine during infection appears to be toxic to tomato cells and does not suppress defense responses, as suggested previously. Altogether, our results show that CfTom1 is responsible for the detoxification of α-tomatine by C. fulvum, and is required for full virulence of this fungus on tomato.

Concepts: Bacteria, Enzyme, Microbiology, Tomato, Solanaceae, Solanum, Potato, Solanine

27

Active uptake of ferric iron in microorganisms is based on siderophores. During iron deficiency, Pseudomonas fluorescens synthesizes siderophores, called pyoverdine, which have a high affinity for ferric iron. Strategy I plants generally cannot synthesize pyoverdine or take up ferric iron. We assessed the effect of pyoverdine chelated to ferric iron on iron nutrition in Solanum lycopersicum. Weight and photosynthetic pigment concentrations in the plants supplemented with the pyoverdine and ferric iron were restored to the rates of plants supplemented with ferrous iron. Leaves and roots accumulated significant iron after pyoverdine and ferric iron supplementation than when supplemented with ferric iron alone. When leaves and roots were supplemented with pyoverdine and ferric iron, the SlFRO1 expression level was suppressed to 20% and 50% relative to those decreased with ferric iron alone, respectively. The level of SlIRT1 in roots supplemented with pyoverdine and ferric iron decreased to 50% compared with the level in roots supplemented with ferric iron alone. These results suggest that SlFRO1 and SlIRT1 expression levels were suppressed and that iron content was restored by pyoverdine and ferric iron supplementation. Thus, the downregulation may have occurred because of negative feedback on mRNA expression. Pyoverdine-mediated ferric iron uptake by tomato is suggested to be a useful strategy to increase iron uptake from the environment.

Concepts: Photosynthesis, Bacteria, Iron, Fruit, Tomato, Solanaceae, Solanum, Ferric

26

Etiological studies of a recently emerged bushy top disease of tobacco in Ethiopia indicated that a ~4.5-kb dsRNA from infected plants represents an umbravirus, whereas a smaller band (~0.5 kb) is that of a new satellite RNA. Potato leafroll virus was also consistently associated with the disease. The three agents, whose experimental host ranges are restricted to members of the family Solanaceae, always occurred together in field samples and are transmitted together by the aphid Myzus persicae nicotianae. The umbravirus, which represents a new species, is most closely related to groundnut rosette virus, and the name Ethiopian tobacco bushy top virus is proposed.

Concepts: Virus, Virology, Viruses, Solanaceae, Potato leafroll virus

26

SOLANUM ELAEAGNIFOLIUM (silverleaf nightshade), having originated in the Americas, is now a serious summer-growing, perennial weed in many countries, including Australia. Most surfaces of the plants have a dense covering of trichomes, giving them a silvery-white appearance, hence the common name. We aimed to identify structural and functional properties of its leaves, especially the trichomes, that may affect the uptake of foliar-applied tracer dyes.

Concepts: Plant, Solanaceae, Solanum, Leaf, Plant morphology, Trichome, Solanum elaeagnifolium, Solanum aculeastrum

23

Atropa belladonna, commonly known as belladonna or deadly nightshade, ranks among one of the most poisonous plants in Europe and other parts of the world. The plant contains tropane alkaloids, including atropine, scopolamine, and hyoscyamine, which are used as anticholinergics in Food and Drug Administration (FDA) approved drugs and homeopathic remedies. These alkaloids can be very toxic at high dose. The FDA has recently reported that Hyland’s baby teething tablets contain inconsistent amounts of Atropa belladonna that may have adverse effects on the nervous system and cause death in children, thus recalled the product in 2017. A greater understanding of the neurotoxicity of Atropa belladonna and its modification of genetic polymorphisms in the nervous system is critical in order to develop better treatment strategies, therapies, regulations, education of at-risk populations, and a more cohesive paradigm for future research. This review offers an integrated view of the homeopathy and neurotoxicity of Atropa belladonna in children, adults and animal models, as well as its implications to neurological disorders. Particular attention is dedicated to the pharmaco/toxicodynamics, pharmaco/toxicokinetics, pathophysiology, epidemiological cases, and animal studies associated with the effects of Atropa belladonna on the nervous system. Additionally, we discuss the influence of active tropane alkaloids in Atropa belladonna and other similar plants on FDA-approved therapeutic drugs for treatment of neurological disorders.

Concepts: Central nervous system, Neurology, Solanaceae, Anticholinergic, Atropine, Hyoscyamine, Atropa belladonna, Atropa