Photomorphogenic modulation of water stress in tomato (Solanum lycopersicum L.): the role of phytochromes A, B1, and B2

Phytochromes are red/far-red light photoreceptors that mediate a variety of photomorphogenic processes in plants, from germination to flowering. In addition, there is evidence that phytochromes are also part of the stress signalling response, especially in response to water deficit stress, which is the major abiotic factor limiting plant growth and crop productivity worldwide. In this study, we used the phyA (far red-insensitive; fri), phyB1 (temporary red-insensitive; tri) and phyB2 mutants of tomato (Solanum lycopersicum L.) to study the roles of these three phytochromes in drought stress responses. Compared to wild type (WT) plants grown under water-deficit stress conditions, the fri, tri, and phyB2 mutants did not exhibit altered dry weights, leaf areas, stomatal densities, or stomatal opening. The stomatal conductance of all three mutants was severely reduced under both fully-hydrated and water-deficit conditions. Although relative water contents did change after drought stress in each mutant, the most significant reduction in water potential during water stress was observed in the fri mutant. However, this mutant returned its water status to WT levels during rehydration. Although the phyB2 mutant lost more water from detached leaves during abscisic acid (ABA) treatment, phyB2 behaved like WT plants, indicating that this mutant was not insensitive to ABA. Overall, these results indicate that the phytochromes phyA, phyB1, and phyB2 modulate drought stress responses in tomato.

In vivo assessment of genotoxic, antigenotoxic and anticarcinogenic activities of Solanum lycocarpum fruits glycoalkaloidic extract

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Optimization of extraction conditions and antioxidant activity of Solanum lycocarpum fruits

Antioxidants are substances that may protect cells from the damage caused by unstable molecules known as free radicals. The capacity of natural antioxidant from phytochemical has increase attention from researchers and public. However, the extraction process is affecting the activity and the bioavailability of bioactive compounds. The Solanum lycocarpum is a plant of the Brazilian “cerrado”, popularly used as a hypoglycemic, hypocholesterolemic and control of metabolic diseases. Its effects are attributed to the presence of several glycoalkaloids (solamargine, solasonina) and solasodine. Therefore, the purpose of this communication was, investigate the optimization of extraction condition and evaluation of antioxidant activity from fruits of Solanum lycocarpum. The extracts were obtained using different solvent systems, i.e., water, 50% ethanol, ethanol absolute and ethyl ether (1:10 and 1:20) and different extraction processes: maceration with constant agitation at room temperature, maceration with constant agitation and heating at 30°C and ultrasound. The extracts were characterized by the amount of material extracted (1, 6 and 24 h) and the action of antioxidant activity by DPPH method. The results showed that the polar solvent (50% ethanol) and extractive process maceration with agitation to ambient temperature showed higher contents of extractable of fruits of S. lycocarpum (3.4 g %) and also showed higher antioxidant activity (88.57±2.41% de inhibition). This action whether the presence of glycoalkaloids (solamargine, solasonine and solasodine) in fruits S. lycocarpum which are polar compounds and may explain this increased antioxidant action of this extract.

Caracterização funcional da via miR159/SlyGAMYB-like ao longo do processo de frutificação em tomateiro (Solanum lycopersicum L.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização funcional da via miR159/SlyGAMYB-like ao longo do processo de frutificação em tomateiro (Solanum lycopersicum L.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Solanum americanum as a reservoir of natural enemies of the tomato red spider mite, Tetranychus evansi (Acari: Tetranychidae)

Brazilian populations of the pathogenic fungus Neozygites floridana (Weiser & Muma) Remaudiere & S. Keller (Entomophthoromycotina: Entomophthorales) and the predatory mite Phytoseiulus longipes Evans (Acari: Phytoseiidae) are potential candidates for introduction into Africa for classical biological control of the tomato red spider mite, Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae). The efficiency of these natural enemies against T. evansi has been demonstrated under laboratory conditions, but little is known about their performance on native Solanaceae in the field. The American nightshade, Solanum americanum Mill., is native to the Americas and may serve as an alternative host plant for T. evansi and its natural enemies in the absence of tomato plants. In this work, we studied the population dynamics of T. evansi and its natural enemies on S. americanum in a screen house, semi-field and field plots in Recife, Pernambuco, Brazil, to evaluate the potential of natural enemies for controlling T. evansi. Of the four natural enemies found in association with T. evansi, only N. floridana and P. longipes were clearly associated with the reduction of the populations of T. evansi. Neozygites floridana was observed in a screen house, semi-field and field plots, but P. longipes was only detected in the semi-field plots. Increases in the population of T. evansi were always followed by increases in the density of one of these natural enemies, suggesting that they were important factors regulating T. evansi populations on S. americanum. The presence of this host plant near the release sites in Africa thus might increase the chances for the permanent establishment of these natural enemies.

A Validated Reverse Phase HPLC Analytical Method for Quantitation of Glycoalkaloids in Solanum lycocarpum and Its Extracts

Solanum lycocarpum (Solanaceae) is native to the Brazilian Cerrado. Fruits of this species contain the glycoalkaloids solasonine (SN) and solamargine (SM), which display antiparasitic and anticancer properties. A method has been developed for the extraction and HPLC-UV analysis of the SN and SM in different parts of S. lycocarpum, mainly comprising ripe and unripe fruits, leaf, and stem. This analytical method was validated and gave good detection response with linearity over a dynamic range of 0.77-1000.00 mu g mL(-1) and recovery in the range of 80.92-91.71%, allowing a reliable quantitation of the target compounds. Unripe fruits displayed higher concentrations of glycoalkaloids (1.04% +/- 0.01 of SN and 0.69% +/- 0.00 of SM) than the ripe fruits (0.83% +/- 0.02 of SN and 0.60% +/- 0.01 of SM). Quantitation of glycoalkaloids in the alkaloidic extract gave 45.09% +/- 1.14 of SN and 44.37% +/- 0.60 of SM, respectively.

Leaf cuticular alkanes of Solanum subg. Leptostemonum Dunal (Bitter) of some northeast Brazilian species: Composition and taxonomic significance

Solanum subgenus Leptostemonum (Dunal) Bitter comprises approximately 450 species, of which 110, including 58 endemics, occur in Brazil, which is recognized as one of the centers of diversity of the group. Due the great morphological plasticity and its large number of species, several taxonomic treatments have been proposed for the genus Solanum, but its infrageneric classification is problematic. The aim of this study was to analyze the alkane composition of the leaf epicuticular waxes of nine species of the subgenus Leptostemonum to evaluate the chemotaxonomic potential of the alkanes. As results, were identified in nine species thirty-one alkanes, including iso- and anteiso-alkanes. The major constituent of wax in most species was tritriacontane. Hentriacontane was the main constituent of Solanum paraibanum and Solanum torvum, and penta-triacontane was predominant in different populations of Solanum stramonifolium. The phenetic analysis of nine species based on the distribution profile of alkanes (Euclidean distance and UPGMA method) show three clusters with distinct main homolog. The profiles of alkanes showed some qualitative taxonomic value for species analyzed, although, a larger number of representative samples of this subgenus must be investigated. (C) 2012 Elsevier Ltd. All rights reserved.

Evaluation of the schistosomicidal activity of the steroidal alkaloids from Solanum lycocarpum fruits

Solanum lycocarpum (Solanaceae), a Brazilian medicinal plant known as "wolf fruit," contains about 1.5% of glycoalkaloids in its dried fruits, consisting mainly of solamargine and solasonine. The present work reports the obtainment of the alkaloidic extract of the S. lycocarpum fruit by acid-base extraction and the isolation of the major alkaloid heterosides by chromatographic means, as well as the evaluation of their in vitro schistosomicidal activities. The in vitro schistosomicidal activities of the alkaloidic extract of S. lycocarpum fruits and its isolated steroidal alkaloids were undertaken against adult worms of Schistosoma mansoni. The alkaloidic extract (20, 32, and 50 mu g mL(-1)), solasonine (50 mu M), solamargine (32 and 50 mu M), and equimolar mixture of glycoalkaloids (20, 32, and 50 mu M) lead to the separation of all couple worms and extensive disruption on their teguments, such as sloughing, as well as their deaths within 24 h of incubation. In addition, the alkaloidic extract (10 and 15 mu g mL(-1)), solasonine (50 mu M), solamargine (10, 15, and 20 mu M), and equimolar mixtures of glycoalkaloids (10 and 15 mu M) reduced the development of eggs produced by the adult worms. Solamargine, containing the sugar chain moiety chacotriose, was more active than the solasonine, which contains solatriose sugar chain moiety. A synergistic effect was also observed for a mixture of solamargine and solasonine. Therefore, the alkaloidic extract of S. lycocarpum, and its major components, solamargine and solasonine, showed promising schistosomicidal activity.

Evaluation of cytotoxic, genotoxic and antigenotoxic potential of Solanum lycocarpum fruits glicoalkaloid extract in V79 cells

Solanum lycocarpum St.-Hil (Solanaceae) is a hairy shrub or small much-branched tree of the Brazilian Cerrado, popularly known as "fruit-of-wolf". Considering that the induction of chromosomal mutations is involved in the process of carcinogenesis, and that S. lycocatpum is often used in folk medicine, it becomes relevant to study its effect on genetic material. In this sense, the aim of present study was to determine the possible cytotoxic, genotoxic and antigenotoxic potentials of S. lycocarpum fruits glycoalkaloid extract (SL) in Chinese hamster lung fibroblasts (V79 cells). The cytotoxicity was evaluated by the colony forming assay, apoptosis and necrosis assay. Trypan blue exclusion dye method and mitotic index. Genotoxic and antigenotoxic potential were evaluated by comet and chromosomal aberrations assays. Four concentrations of SL (4, 8, 16 and 32 mu g/mL) were used for the evaluation of its genotoxic potential. The DNA damage-inducing agent methyl methanesulfonate (MMS, 221 mu g/mL) was utilized in combination with extract to evaluate a possible protective effect. The results showed that SL was cytotoxic at concentrations above 32 mu g/mL by the colony forming assay. For apoptosis and necrosis assay, the concentration of 64 mu g/mL of SL showed statistically significant increase in cell death by apoptosis and necrosis, while the concentrations of 128 and 256 mu g/mL of SL demonstrated statistically significant increase in cell death by necrosis, compared with the control group. Analysis of cell viability by Trypan blue exclusion indicated >96% viability for treatments with concentrations up to 32 mu g/mL of SL No significant differences in MI were observed between cultures treated with different concentrations of 51 (4, 8, 16 and 32 mu g/mL) alone or in combination with MMS and the negative control, indicating that these treatments were not cytotoxic. The comet and chromosomal aberrations assays revealed that SL does not display genotoxic activity. Moreover, the different concentrations of SL showed protective effect against both genomic and chromosomal damages induced by MMS. (C) 2012 Elsevier Ltd. All rights reserved.

The Tomato (Solanum Lycopersicum cv. Micro-Tom) Natural Genetic Variation Rg1 and the DELLA Mutant Procera Control the Competence Necessary to Form Adventitious Roots and Shoots

Despite the wide use of plant regeneration for biotechnological purposes, the signals that allow cells to become competent to assume different fates remain largely unknown. Here, it is demonstrated that the Regeneration1 (Rg1) allele, a natural genetic variation from the tomato wild relative Solanum peruvianum, increases the capacity to form both roots and shoots in vitro; and that the gibberellin constitutive mutant procera (pro) presented the opposite phenotype, reducing organogenesis on either root-inducing medium (RIM) or shoot-inducing medium (SIM). Mutants showing alterations in the formation of specific organs in vitro were the auxin low-sensitivity diageotropica (dgt), the lateral suppresser (ls), and the KNOX-overexpressing Mouse ears (Me). dgt failed to form roots on RIM, Me increased shoot formation on SIM, and the high capacity for in vitro shoot formation of ls contrasted with its recalcitrance to form axillary meristems. Interestingly, Rg1 rescued the in vitro organ formation capacity in proRg1 and dgtRg1 double mutants and the ex vitro low lateral shoot formation in pro and ls. Such epistatic interactions were also confirmed in gene expression and histological analyses conducted in the single and double mutants. Although Me phenocopied the high shoot formation of Rg1 on SIM, it failed to increase rooting on RIM and to rescue the non-branching phenotype of ls. Taken together, these results suggest REGENERATION1 and the DELLA mutant PROCERA as controlling a common competence to assume distinct cell fates, rather than the specific induction of adventitious roots or shoots, which is controlled by DIAGEOTROPICA and MOUSE EARS, respectively.

A New Cryptically Dioecious Species of Bush Tomato (Solanum) From the Northern Territory, Australia

A new species of dioecious Solanum from the Australian “Dioicum Complex” of Solanum subgenus Leptostemonum is described. Solanum cowiei Martine sp. nov., is allied with other members of this problematic lineage, but differs in its slender leaves, limited armature and diminutive habit. The species was first segregated by botanists at the Northern Territory Herbarium as Solanum sp. Litchfield (I.D. Cowie 1428); and specimens representing this species have also been referred to by Symon as Solanum sp. Fitzmaurice River. Collections suggest that this is an endemic of the sub-arid tropical zone of the Northern Territory. SEM images support initial assumptions that the new species is cryptically dioecious via production of inaperturate pollen grains in morphologically hermaphrodite flowers.

Selective uptake, distribution, and redistribution of Cd-109, Co-57, Zn-65, Ni-63, and Cs-134 via xylem and phloem in the heavy metal hyperaccumulator Solanum nigrum L

The focus of this article was to explore the translocation of Cd-109, Co-57, Zn-65, Ni-63, and Cs-134 via xylem and phloem in the newly found hyperaccumulator Solanum nigrum L. Two experiments with the uptake via the roots and transport of Cd-109, Co-57, and Zn-65 labeled by roots, and the redistribution of Cd-109, Zn-65, Co-57, Ni-63, and Cs-134 using flap label in S. nigrum in a hydroponic culture with a standard nutrient solution were conducted. The results showed that Cd-109 added for 24 h to the nutrient medium of young plants was rapidly taken up, transferred to the shoot, and accumulated in the cotyledons and the oldest leaves but was not efficiently redistributed within the shoot afterward leading to a rather low content in the fruits. In contrast, Co-57 was more slowly taken up and released to the shoot, but afterward, this element was redistributed from older leaves to younger leaves and maturing fruits. Zn-65 was rapidly taken up and transferred to the shoot (mainly to the youngest leaves and not to the cotyledons). Afterward, this radionuclide was redistributed within the shoot to the youngest organs and finally accumulated in the maturing fruits. After flap labeling, all five heavy metals tested (Cd-109, Co-57, Zn-65, Ni-63, Cs-134) were exported from the labeled leaf and redistributed within the plant. The accumulation in the fruits was most pronounced for Ni-63 and Zn-65, while a relatively high percentage of Co-57 was finally found in the roots. Cs-134 was roughly in the middle of them. The transport of Cd-109 differed from that previously reported for wheat or lupin and might be important for the potential of S. nigrum to hyperaccumulate cadmium.