A novel approach to Cestrum intermedium (mata-boi): anatomical and physical-chemical characterization, in vitro biological activities, and metabolites of a Brazilian native species

Abstract The Brazilian native species Cestrum intermedium, known as mata-boi, induces hepatotoxicity and death when ingested by cattle. While most studies on this species focus on toxicological features, our study is the first to describe the anatomy and in vitro biological activities of Cestrum intermedium. We investigated adult leaves and stems by histochemistry, described their anatomy, performed physical-chemical analysis, determined in vitro antioxidant and antimicrobial activities, and identified secondary metabolites. A few noteworthy anatomical features were the anomocytic stomata on the abaxial surface and the absence of trichomes, in addition to the circular shaped petiole with two projections on the adaxial surface. Histochemical analysis showed chemical markers such as alkaloids, usually reported as toxic, and terpenoids. Potassium nitrate (ATR-FTIR) and lupeol palmitate (NMR) were detected on the crude stem extract. Thermogravimetric and physical-chemical analysis provided fingerprint parameters for the species. Minimal Inhibitory Concentration (MIC) assay revealed that Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans were weakly inhibited by extract samples. Chloroform and ethyl acetate fractions presented high phenolic content, which resulted in in vitro antioxidant activity. These novel features expand the knowledge about this species, considering that previous studies mainly focused on its toxicity. Our study also provided characteristics that may help in avoiding misidentification between Cestrum members, especially when taxonomic keys cannot be employed, as in the absence of flowers and fruits.

Unravelling the structure and function of the petal appendages in the tribe Schwenckieae (Solanaceae).

The tribe Schwenckieae (Solanaceae) is characterised by the presence of appendages on the corolla, a diagnostic trait for the group. These appendages constitute a median distal projection of the three-lobed petal and occur in the genera Melananthus and Schwenckia but are absent in Heteranthia. We investigated the micromorphology and anatomical structure of the appendages and lateral petal lobes of Schwenckia americana (two varieties), S. angustifolia, S. curviflora and S. novaveneciana, and Melananthus fasciculatus. We also performed histochemical tests to determine if the appendages are involved in the production of volatiles, acting as a fragrance secretory structure (osmophore). The appendages have a uniseriate epidermis, whose cells store phenolics and lipids. The parenchyma is starch-rich just prior to anthesis in all species studied. The sensory test and anatomical analyses identified scent-secreting tissues, not only in the appendages, but also in the lateral petal lobes, whose cells are papillose with a sculptured surface. The α-naphthol p-phenylenediamine (NADI) reaction detected volatile (essential oils) compounds in S. americana var. americana and S. americana var. angustifolia. We demonstrated the secretory tissues and the production of lipids in the corolla appendages of Schwenckia and Melananthus, which indicate their osmogenic function and probable scent emission to attract pollinators.

Early consequences of allopolyploidy alter floral evolution in Nicotiana (Solanaceae).

BACKGROUND: Polyploidy has played a major role in angiosperm evolution. Previous studies have examined polyploid phenotypes in comparison to their extant progenitors, but not in context of predicted progenitor phenotypes at allopolyploid origin. In addition, differences in the trends of polyploid versus diploid evolution have not been investigated. We use ancestral character-state reconstructions to estimate progenitor phenotype at allopolyploid origin to determine patterns of polyploid evolution leading to morphology of the extant species. We also compare trends in diploid versus allopolyploid evolution to determine if polyploidy modifies floral evolutionary patterns. RESULTS: Predicting the ancestral phenotype of a nascent allopolyploid from reconstructions of diploid phenotypes at the time of polyploid formation generates different phenotype predictions than when extant diploid phenotypes are used, the outcome of which can alter conclusions about polyploid evolution; however, most analyses yield the same results. Using ancestral reconstructions of diploid floral phenotypes indicate that young polyploids evolve shorter, wider corolla tubes, but older polyploids and diploids do not show any detectable evolutionary trends. Lability of the traits examined (floral shape, corolla tube length, and corolla tube width) differs across young and older polyploids and diploids. Corolla length is more evolutionarily labile in older polyploids and diploids. Polyploids do not display unique suites of floral characters based on both morphological and color traits, but some suites of characters may be evolving together and seem to have arisen multiple times within Nicotiana, perhaps due to the influence of pollinators. CONCLUSIONS: Young polyploids display different trends in floral evolution (shorter, wider corolla tubes, which may result in more generalist pollination) than older polyploids and diploids, suggesting that patterns of divergence are impacted by the early consequences of allopolyploidy, perhaps arising from genomic shock and/or subsequent genome stabilization associated with diploidization. Convergent evolution in floral morphology and color in Nicotiana can be consistent with pollinator preferences, suggesting that pollinators may have shaped floral evolution in Nicotiana.

Scanning Electron Microscopy (SEM) and Light Microscopy (LM)-based Palyno-morphological views of Solanaceae in Western Himalaya.

In this study, plants belonging to family Solanaceae growing in Western Himalaya region have been observed palynologically under Light Microscope and Scanning electron microscope. Present investigation comprises of 10 genera and 23 species, namely, Atropa acuminata, Capsicum decoraticus, Capsicum frutescens, Cestrum aurantiacum, Cestrum diurnum, Cestrum nocturnum, Datura alba, Datura innoxia, Datura stramonium, Hyoscymus niger, Lycopersicon esculentum, Nicotiana rustica, Nicotiana tabacum, Petunia alba, Petunia hybrida, Solanum erianthum, Solanum melongena, Solanum miniatum, Solanum pseudocapsicum, Solanum surratense, Solanum tuberosum, Withania coagulans, Withania somnifera. Solanaceae is a eurypalynous family. Grains are usually Tricolporate and Tetracolporate, radially symmetrical, isopolar, prolate-spheroidal to oblate-spheroidal to oblate-spheroidal to subprolate to per prolate or suboblate to oblate, size range: 8.55-72 µm, amb circular, semi-angular or subangular, aperture drop-type, labrum common-type, exine usually 2 µm thick, nexine 1-1.5 µm thick. Tectum usually psilate, sexine reticulate, granulate or striato-reticulate, with obscure pattern, sexine 1-2 µm thick, nexine 1-1.5 µm thick, and intine 0.5-1 µm thick. Most striking variation has been found in the shape class, aperture-type, and tectal surface. Based on these characters, taxonomic keys have been made for correct identification of members in Solanaceae. However, the grains of this family are usually tricolporate and have direct relationship with certain members of the family Scrophulariaceae. Palyno-morphological characters of family Solanaceae have been studied for the first time in Western Himalayan region of Pakistan. These palyno-morphological characters are significant for identification of the members of family Solanaceae.

A new commelinid monocot seed fossil from the early Eocene previously identified as Solanaceae.

PREMISE OF THE STUDY: Fossils provide minimum age estimates for extant lineages. Here we critically evaluate Cantisolanum daturoides Reid & Chandler and two other early putative seed fossils of Solanaceae, an economically important plant family in the Asteridae. METHODS: Three earliest seed fossil taxa of Solanaceae from the London Clay Formation (Cantisolanum daturoides) and the Poole and Branksome Sand Formations (Solanum arnense Chandler and Solanispermum reniforme Chandler) were studied using x-ray microcomputed tomography (MCT) and scanning electron microscopy (SEM). KEY RESULTS: The MCT scans of Cantisolanum daturoides revealed a high level of pyrite preservation at the cellular level. Cantisolanum daturoides can be clearly excluded from Solanaceae and has more affinities to the commelinid monocots based on a straight longitudinal axis, a prominent single layer of relatively thin-walled cells in the testa, and a clearly differentiated micropyle surrounded by radially elongated and inwardly curved testal cells. While the MCT scans show no internal preservation in Solanum arnense and Solanispermum reniforme, SEM images show the presence of several characteristics that allow the placement of these taxa at the stem node of Solanaceae. CONCLUSIONS: Cantisolanum daturoides is likely a member of commelinid monocots and not Solanaceae as previously suggested. The earliest fossil record of Solanaceae is revised to consist of fruit fossil with inflated calyces from the early Eocene of Patagonia (52 Ma) and fossilized seeds from the early to mid-Eocene of Europe (48-46 Ma). The new identity for Cantisolanum daturoides does not alter a late Cretaceous minimum age for commelinids.

Evolution of genes associated with gynoecium patterning and fruit development in Solanaceae.

Background and Aims: The genetic basis of fruit development has been extensively studied in Arabidopsis, where major transcription factors controlling valve identity (i.e. FRUITFULL), replum development (i.e. REPLUMLESS) and the differentiation of the dehiscence zones (i.e. SHATTERPROOF, INDEHISCENT and ALCATRAZ) have been identified. This gene regulatory network in other flowering plants is influenced by duplication events during angiosperm diversification. Here we aim to characterize candidate fruit development genes in the Solanaceae and compare them with those of Brassicaceae. Methods: ALC/SPT, HEC/IND, RPL and AG/SHP homologues were isolated from publicly available databases and from our own transcriptomes of Brunfelsia australis and Streptosolen jamesonii. Maximum likelihood phylogenetic analyses were performed for each of the gene lineages. Shifts in protein motifs, as well as expression patterns of all identified homologues, are shown in dissected floral organs and fruits in different developmental stages of four Solanaceae species exhibiting different fruit types. Key Results: Each gene lineage has undergone different duplication time-points, resulting in very different genetic complements in the Solanaceae when compared with the Brassicaceae. In general, Solanaceae species have more copies of HEC1/2 and RPL than Brassicaceae, have fewer copies of SHP and the same number of copies of AG, ALC and SPT. Solanaceae lack IND orthologues, but have pre-duplication HEC3 homologues. The expression analyses showed opposite expression of SPT and ALC orthologues between dry- and fleshy-fruited species during fruit maturation. Fleshy-fruited species turn off RPL and SPT orthologues during maturation. Conclusions: The gynoecium patterning and fruit developmental genetic network in the Brassicaceae cannot be directly extrapolated to the Solanaceae. In Solanaceae ALC, SPT and RPL contribute differently to maturation of dry dehiscent and fleshy fruits, whereas HEC genes are not generally expressed in the gynoecium. RPL genes have broader expression patterns than expected.

Convergent evolution of floral shape tied to pollinator shifts in Iochrominae (Solanaceae).

Flower form is one of many floral features thought to be shaped by pollinator-mediated selection. Although the drivers of variation in flower shape have often been examined in microevolutionary studies, relatively few have tested the relationship between shape evolution and shifts in pollination system across clades. In the present study, we use morphometric approaches to quantify shape variation across the Andean clade Iochrominae and estimate the relationship between changes in shape and shifts in pollination system using phylogenetic comparative methods. We infer multiple shifts from an ancestral state of narrow, tubular flowers toward open, bowl-shaped, or campanulate flowers as well as one reversal to the tubular form. These transitions in flower shape are significantly correlated with changes in pollination system. Specifically, tubular forms tend to be hummingbird-pollinated and the open forms tend to be insect-pollinated, a pattern consistent with experimental work as well as classical floral syndromes. Nonetheless, our study provides one of the few empirical demonstrations of the relationship between flower shape and pollination system at a macroevolutionary scale.

Coloration of the Chilean Bellflower, Nolana paradoxa, interpreted with a scattering and absorbing layer stack model.

MAIN CONCLUSION: An absorbing-layer-stack model allows quantitative analysis of the light flux in flowers and the resulting reflectance spectra. It provides insight in how plants can optimize their flower coloration for attracting pollinators. The coloration of flowers is due to the combined effect of pigments and light-scattering structures. To interpret flower coloration, we applied an optical model that considers a flower as a stack of layers, where each layer can be treated with the Kubelka-Munk theory for diffusely scattering and absorbing media. We applied our model to the flowers of the Chilean Bellflower, Nolana paradoxa, which have distinctly different-colored adaxial and abaxial sides. We found that the flowers have a pigmented, strongly scattering upper layer, in combination with an unpigmented, moderately reflecting lower layer. The model allowed quantitative interpretation of the reflectance and transmittance spectra measured with an integrating sphere. The absorbance spectrum of the pigment measured with a microspectrophotometer confirmed the spectrum derived by modeling. We discuss how different pigment localizations yield different reflectance spectra. The absorbing layer stack model aids in understanding the various constraints and options for plants to tune their coloration.

Distinct cell wall architectures in seed endosperms in representatives of the Brassicaceae and Solanaceae.

In some species, a crucial role has been demonstrated for the seed endosperm during germination. The endosperm has been shown to integrate environmental cues with hormonal networks that underpin dormancy and seed germination, a process that involves the action of cell wall remodeling enzymes (CWREs). Here, we examine the cell wall architectures of the endosperms of two related Brassicaceae, Arabidopsis (Arabidopsis thaliana) and the close relative Lepidium (Lepidium sativum), and that of the Solanaceous species, tobacco (Nicotiana tabacum). The Brassicaceae species have a similar cell wall architecture that is rich in pectic homogalacturonan, arabinan, and xyloglucan. Distinctive features of the tobacco endosperm that are absent in the Brassicaceae representatives are major tissue asymmetries in cell wall structural components that reflect the future site of radicle emergence and abundant heteromannan. Cell wall architecture of the micropylar endosperm of tobacco seeds has structural components similar to those seen in Arabidopsis and Lepidium endosperms. In situ and biomechanical analyses were used to study changes in endosperms during seed germination and suggest a role for mannan degradation in tobacco. In the case of the Brassicaceae representatives, the structurally homogeneous cell walls of the endosperm can be acted on by spatially regulated CWRE expression. Genetic manipulations of cell wall components present in the Arabidopsis seed endosperm demonstrate the impact of cell wall architectural changes on germination kinetics.

Plant hormones including ethylene are recruited in calyx inflation in Solanaceous plants.

Plant hormones direct many processes of floral and post-floral morphogenesis in Angiosperms. However, their role in shaping floral morphological novelties, such as inflated calyx syndrome (ICS) exhibited by a few genera of the Solanaceae, remains unknown. In Withania and Physalis, sepals resume growth after pollination and encapsulate the mature fruit to form a balloon-like structure, i.e. ICS. The epidermal cells of calyx show enlargement and lobation post-fertilization. Application of hormones to depistillated flower buds of Withania revealed that cytokinins and gibberellins mimic fertilization signals. The ICS development is a synchronous step with fruit development; both processes are under the control of more or less the same set of hormones, including cytokinins and gibberellic acids. Interestingly, inhibition of ethylene in the system is sufficient to yield inflated calyx in Withania. In contrast, Tubocapsicum, a closely related species and an evolutionary natural loss mutant of ICS - showed no response to applied hormones, and ethylene led to inflation of the receptacle indirectly. In addition to hormones, the expression of an MPF2-like MADS-box transcription factor in sepals is essential for ICS formation. Nevertheless, the interactions between MPF2-like genes and hormones are barely detectable at the transcript level. Our data provide insight into the role of hormones in generating floral morphological diversity during evolution.

Brunfelsia (Solanaceae): a genus evenly divided between South America and radiations on Cuba and other Antillean islands.

Hallucinogenic or toxic species of Brunfelsia (Solanaceae: Petunieae) are important in native cultures throughout South America, and the genus also contains several horticulturally important species. An earlier morphological revision of the c. 50 species recognized three main groups, one consisting of the 23 Antillean species, another of southern South American and Andean species, and a third of species from the Amazon Basin and Guiana Shield. Based on plastid and nuclear DNA sequences from up to 65 accessions representing 80% of the species, we generated a phylogeny and a calibrated chronogram for Brunfelsia to infer clade expansion and shifts in pollinators and fruit types. Brunfelsia flowers offer nectar, and attract lepidoptera, hummingbirds, or bees; the fruits are dry or fleshy. Our results imply that Brunfelsia is 16-21 Myr old and entered the Antilles from South America early during its history, with subsequent expansion along the island arc. The ancestor of the Antillean clade was hawk-moth-pollinated and had fleshy capsules, perhaps facilitating dispersal by birds. The only shift to hummingbird pollination occurred on Cuba, which also harbors the largest single radiation, with 11 species (10 included in our study) that apparently arose over the past 4 Myr. Jamaica, Hispaniola, and Puerto Rico each sustained smaller radiations. The data also reveal at least one new species.

Comparative anatomical and developmental analysis of dry and fleshy fruits of Solanaceae.

PREMISE OF THE STUDY: An anatomical examination of dry and fleshy fruits within the Solanaceae was carried out to identify comparable stages throughout development as well as features exclusive to each type of fruit. We studied fruit development of Nicotiana and Petunia, which have the plesiomorphic capsular fruit; Solanum and Iochroma, characterized by a derived fleshy berry; Cestrum, an independent origin of a fleshy fruit; and Datura, a reversion to a dry fruit. • METHODS: Pre- and postanthesis carpels and fruits of all species were collected, sectioned, stained, and examined using light microscopy. • KEY RESULTS: Comparable stages of carpel and fruit development were identified in all species. Furthermore, anatomical and developmental features were identified that characterize capsules in Solanaceae, including lack of increase in the number of pericarp cell layers, formation of a sclerified endocarp, and elongation of the epidermal cells of the placenta. Pericarps of fleshy fruits of the Solanoideae are characterized by abundant collenchyma, an increase in the number of cell layers, and a parenchymatous endocarp often expanding into the locules. Anatomical data show that early developmental stages of the fruit of Cestrum, a berry, are similar to the capsular fruits of Petunia and Nicotiana; similarly, Datura, one of the few capsular members of the Solanoideae, shares several anatomical features with closely related berried taxa. • CONCLUSIONS: Ontogenetically, all fleshy or all dry fruits do not necessarily share a common developmental ground plan. Independent evolution of fleshiness, sclerification, dryness, and dehiscence are discussed in a phylogenetic context.

Leaf epidermal characters of Solanum sect. polytrichum (Solanaceae) as taxonomic evidence.

The morphological similarities among the species of Solanum are remarkable, and are often very difficult one clear distinction between them. This paper presents a comparative anatomical study of the leaf epidermis of five Brazilian species of Solanum sect. Polytrichum, carried out using light and scanning electron microscopy. The leaf epidermis surfaces were investigated to evaluate their taxonomic significance to be used for separation and delimitation of the species of the section. As results, some micro-morphological characters of the leaf epidermis, such as density, distribution and type of stellate trichomes, and the anticlinal walls of epidermal cells, and also the type and distribution of stomata proved to be the most useful and distinctive characters for the separation and delimitation of the species, and also may contribute as an additional support to the interspecific taxonomy and systematic of Solanum sect. Polytrichum.

On 'various contrivances': pollination, phylogeny and flower form in the Solanaceae.

Members of the euasterid angiosperm family Solanaceae have been characterized as remarkably diverse in terms of flower morphology and pollinator type. In order to test the relative contribution of phylogeny to the pattern of distribution of floral characters related to pollination, flower form and pollinators have been mapped onto a molecular phylogeny of the family. Bilateral flower symmetry (zygomorphy) is prevalent in the basal grades of the family, and more derived clades have flowers that are largely radially symmetric, with some parallel evolution of floral bilateralism. Pollinator types ('syndromes') are extremely homoplastic in the family, but members of subfamily Solanoideae are exceptional in being largely bee pollinated. Pollinator relationships in those genera where they have been investigated more fully are not as specific as flower morphology and the classical pollinator syndrome models might suggest, and more detailed studies in some particularly variable genera, such as Iochroma and Nicotiana, are key to understanding the role of pollinators in floral evolution and adaptive radiation in the family. More studies of pollinators in the field are a priority.

Inflorescence architecture: the transition from branches to flowers.

The shapes of flowers and their organization into branching systems, called inflorescences, dictate much of plant diversity. Recent studies have identified key regulators in this diversity, revealing that the inflorescence architecture of Solanaceous species depends on sequential and temporal expression of the WUSCHEL-RELATED HOMEOBOX (WOX) gene EVERGREEN (EVG)/ COMPOUND INFLORESCENCE (S) and the UNUSUAL FLORAL ORGANS (UFO) ortholog DOUBLE TOP (DOT)/ANANTHA (AN).

Morphological, anatomical, macro and micromolecular markers for Solanum cernuum identification

The plants consumed as remedy by the population may have imprecise taxonomical identification. If these plants are used for the production of phytomedicines such misidentification may affect the quality of the product. Hereby, we describe markers for identification of the entire plant or grounded plant material or the crude extract of Solanum cernuum Vell. (Solanaceae). Specimens from four localities were collected, analyzed and compared. Morphological characters were used to identify the plant when it is not grounded or extracted. However, when the plant material is grounded, the set of trichomes may be used as anatomical marker. The region ITS1, 5.8S and ITS2 of the nuclear ribosomal DNA was cloned and sequenced. The sequence, with length of about 600 base pairs, being 48.1 percent AT , was deposited in GenBank under the accession number DQ837371. Once this sequence is specific to S. cernuum, it was used as marker for this species. For the crude extract, chromatographic profiles of the leaves extracts were obtained by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Two flavonoids were isolated and identified as quercitrin and afzelin. So, this study presents morphological, anatomical, macro and micromolecular markers to identify S. cernuum.

Plantas consumidas como remédio nem sempre são identificadas taxonomicamente de maneira correta. Se estas plantas forem utilizadas para obtenção de uma droga vegetal ou um fitoterápico, tal erro pode afetar a qualidade do produto final. Neste trabalho são descritos marcadores para a identificação de Solanum cernuum Vell. (Solanaceae), esteja a planta íntegra, triturada ou como extrato bruto. Indivíduos de quatro localidades de Minas Gerais foram coletados, analisados e comparados. Os caracteres morfológicos foram utilizados para a planta íntegra. Para a planta triturada, o conjunto dos tricomas foi utilizado como marcador anatômico. Um marcador macromolecular também foi determinado. Para tal a região ITS1, 5.8S e ITS2 do DNAr foi clonada e seqüenciada. A seqüência, com cerca de 600 pares de bases dos quais 48,1 por cento são AT, foi depositada no GenBank sob o número de acesso DQ837371. Por ser uma seqüência específica para S. cernuum, ela pode ser usada como marcador desta espécie. Para o extrato bruto foram determinados perfis cromatográficos de extratos das folhas por cromatografia em camada delgada e por cromatografia líquida de alta eficiência. Dois flavonóides foram isolados e identificados como quercitrina e afzelina. Assim, neste trabalho foram determinados marcadores morfológicos, anatômicos, macro e micromoleculares para identificar S. cernuum.

Evolution of the inflated calyx syndrome in Solanaceae.

Species that express the inflated calyx syndrome (ICS) are found in several genera of the Solanaceae. The MADS-box protein MPF2, together with the plant hormones cytokinin and gibberellin, has been shown to be responsible for this trait in Physalis floridana. We have used sequence data from 114 species belonging to 35 genera to construct a molecular phylogeny of Solanaceae. Apart from the 2 Witheringia species analyzed, species within a given genus cluster together on the resulting cladogram. Witheringia solanacea is embedded within the Physalinae, but Witheringia coccoloboides is placed basal to the Iochrominae. The ICS trait seems to be of multiple origins both within the Solanaceae and the Physaleae. Surprisingly, expression of MPF2-like genes in floral organs appears to be plesiomorphic in both the Physaleae and the Capsiceae. Some species in these tribes that show neither ICS nor calyx accrescence fail to express the MPF2-like gene in floral organs. Among those that do express this gene in the calyx are the species Capsicum baccatum, Lycianthes biflora, Tubocapsicum anomalum, W. solanacea, and Vassobia breviflora, all of which form small calyces that do not respond to externally applied hormones. The plesiomorphic nature of MPF2-like gene expression in the calyx of the Physaleae and Capsiceae raises the possibility that originally ICS also was actually a plesiomorphic character in these 2 groups. However, this trait might have undergone changes in a number of species due to secondary loss of components in ICS formation, like hormone response of calyx development. These findings are discussed in an evolutionary context of a molecular pathway leading to ICS.

Phylogenetic analysis of floral integration in Schizanthus (Solanaceae): does pollination truly integrate corolla traits?

To assess whether floral integration patterns result from the action of pollinator selection on functionally related traits, we compared corolla integration patterns in eight Schizanthus species differing in pollination systems and in their degree of pollinator dependence across a molecular phylogeny. Integration patterns differed among species and these differences were not related to their phylogenetic relatedness. When the putative original function of some corolla traits was lost in pollinator-dependent species, the integration among nonfunctional characters and the rest of the corolla traits was disrupted. This pattern was not presented in species adapted for late autonomous selfing, which exhibited higher corolla integration than their pollinator-dependent relatives. These results suggest that corolla integration in pollinator-dependent species was shaped by pollinator-mediated selection. Decoupling of nonfunctional traits in these species may result from a relaxation of correlational selection or from selection acting against a default covariation provided by genetic and developmental connections.

Control strategies for sweet potato virus disease in Africa.

Sweet potato virus disease (SPVD), caused by dual infection with the whitefly-borne Sweet potato chlorotic stunt virus (SPCSV) and the aphid-borne Sweet potato feathery mottle virus (SPFMV), is the most serious disease of sweet potato in Africa. SPVD has been known there since at least the 1940s, although it took several decades to elucidate its aetiology. It occurs throughout Africa and is particularly prevalent in the Great Lakes region. Production of sweet potato is largely by resource-poor farmers, growing mostly local landraces and for home consumption and so control strategies need to be appropriate to these circumstances. Most high yielding and/or early maturing landraces in Uganda are susceptible to SPVD and most resistant landraces are low-yielding, forcing farmers to compromise between the conflicting requirements of large and/or early yields, and food security. Accordingly, two strategies were tested to avoid the disadvantages associated with such compromises. These were deploying high-yielding SPVD-resistant cultivars and phytosanitation practices to enable susceptible landraces to be grown successfully. In on-farm trials in Masaka and Rakai Districts of Uganda, some SPVD-resistant cultivars bred at Namulonge Agricultural and Animal Research Station (NAARI), in Wakiso District, out-yielded local landraces. Other trials at NAARI and at nearby farms showed that roguing diseased cuttings within 1 month of planting and isolation from diseased crops, even by as little as 15m, can considerably decrease spread of SPVD to susceptible cultivars. This indicates that phytosanitation can protect desirable susceptible cultivars, even if adopted only locally. A dual approach of deploying both resistant varieties and phytosanitation provides farmers with a valuable increase in their choice of control strategies for SPVD.

Dyssochroma viridiflorum (Solanaceae): a reproductively bat-dependent epiphyte from the Atlantic rainforest in Brazil.

Few Neotropical plant species seem to depend on the same animal type both for pollination and seed dispersal, and the known instances refer mostly to birds as the agents in these two phases of a plant reproductive cycle. Dyssochroma viridiflorum (Solanaceae), an epiphyte endemic to the Atlantic rainforest in south-eastern Brazil, was found to be visited by phyllostomid bats for nectar as well as for fruits, with the pollination and seed dispersal of the plant ensured by these flying mammals. The greenish flowers open at night and are visited by the nectar-feeding bat Glossophaga soricina, whereas the yellowish-white fruits are consumed by two species of fruit-eating bats, Carollia perspicillata and Sturnira lilium. Only clinging visits, an uncommon behavioural pattern for glossophagine bats while feeding on flowers, were recorded. The small seeds of D. viridiflorum are swallowed along with the fruit pulp and later defecated on the bats' flying pathways. It is suggested that species of Dyssochroma and two other solanaceous bat-pollinated genera, Merinthopodium and Trianaea, form a derived and bat-dependent clade within the Juanulloeae.