Characterization of the cholesterol biosynthetic pathway in Dioscorea transversa.

Cholesterol is the precursor of bioactive plant metabolites such as steroidal saponins. An Australian plant, Dioscorea transversa, produces only two steroidal saponins: 1ß-hydroxyprotoneogracillin and protoneogracillin. Here, we used D. transversa as a model in which to elucidate the biosynthetic pathway to cholesterol, a precursor to these compounds. Preliminary transcriptomes of D. transversa rhizome and leaves were constructed, annotated, and analyzed. We identified a novel sterol side-chain reductase as a key initiator of cholesterol biosynthesis in this plant. By complementation in yeast, we determine that this sterol side-chain reductase reduces Δ24,28 double bonds required for phytosterol biogenesis as well as Δ24,25 double bonds. The latter function is believed to initiate cholesterogenesis by reducing cycloartenol to cycloartanol. Through heterologous expression, purification, and enzymatic reconstitution, we also demonstrate that the D. transversa sterol demethylase (CYP51) effectively demethylates obtusifoliol, an intermediate of phytosterol biosynthesis and 4-desmethyl-24,25-dihydrolanosterol, a postulated downstream intermediate of cholesterol biosynthesis. In summary, we investigated specific steps of the cholesterol biosynthetic pathway, providing further insight into the downstream production of bioactive steroidal saponin metabolites.

Indigenous biosystematics of yams (Dioscorea spp.) in Southwest Ethiopia: folk taxonomy, ethnolinguistic analysis, and folk descriptors.

BACKGROUND: In Southwest Ethiopia, various plant species are coexisting in wild and cultivated forms. This provides an ideal setting for studying folk biosystematics of neglected species. One of such species is the Dioscorea species, in which we studied to assess the commonly applied folk wisdom of identifying, naming, and classifying yams by Sheko and Bench farmers. METHODS: This study was conducted in Bench-Maji and Sheka Zones using 272 farmers. Data on the lists of local names and system of folk taxonomy; the inherent logic, etymons, and consistency of names; and the folk descriptors and other criteria involved in taxonomy were collected. Data were collected by establishing participatory research appraisal tools, i.e., informant interviews and researcher direct observation. RESULTS: The result suggests that there exists a well-developed folk taxonomic system in Sheko and Bench. This is evident in the recognition of four distinct folk ranks: sub-variety, variety, supra-variety, and folk generic. Taxa assigned to each ranks have distinct features that mark them as members of a separate categories. Farmers over-differentiate 58 individual taxa at the intraspecific levels. Of these, 37 represented varietal taxa while the rest are sub-varietal taxa. Structurally, over 78% of the varieties are labeled with unitary names while all the sub-varieties consisted of binomial names. Farmers used a total of 26 characters and 74 character states for identifying the different taxa. More than 84% of these refer to aspects of plant characteristics. Tuber characters played a key role in the local identification of varietal and sub-varietal taxa while contexts and gender played a key role in the recognition of supra-variety groups. CONCLUSIONS: This study documented a great wealth of knowledge on indigenous biosystematics of yams, constitutes an essential step towards setting development priorities aimed at in situ conservation. The study clearly demonstrated the value of folk biosystematics for assessing the actual extent and spatial dynamics of yam diversity in traditional farming.

[Identification of Dioscorea nipponica and its sects based on psbA-trnH barcode].

A rapid and accurate method was established by psbA-trnH sequence to distinguish Dioscorea nipponica from other species belonging to the same genus.In this study, we collected 144 samples of D. nipponica from 17 different producing areas in China, the psbA-trnH sequenced of 23 nucleotide sequences were downloaded from GenBank, the sequences from Dioscorea genus. DNAMAN 8.0 software was used to show splicing, MEGA 6.0 software was applied for sequence analysis and comparison. The results showed that the genetic relationship between D. nipponica and D. subcalva was the closest, and the genetic relationship with D. zingiberensis was the furthest. It is indicated that the psbA-trnH sequence as a DNA barcode can effectively distinguish between D. nipponica and other plants in the genus of Dioscorea.

[Research progress of Bixie].

The Dioscorea hypoglauca rhizome and D. spongiosa rhizome in "China Pharmacopoeia" are often used as Bixie in clinically, with the function of removing dampness, clearing away turbidness and dispelling wind to remove pain, and has been widely used in stranguria marked by chyluria, joint stiffness and rheumatic arthralgia. It has obvious curative effect and broad application prospect. However, in recent years the progress of research is slow for its miscellaneous sources, chaotic varieties and lack of relevant quality assessment. The previous research on Bixie is mainly reflected in the chemical compositions, mainly including steroids, diarylheptanoids and lignans and so on. Among them, steroidal saponins are the main components and the main effective substances for their pharmacological activities. Recent studies have shown that Bixie and its main components have significant effects in anti-trioxypurine, anti-inflammation, analgesia and anti-osteoporosis, and have made great progress, providing an experimental basis for the research and development of clinical drugs. But the specific substance and specific mechanism of its pharmacological action are not clear, and need further exploration. By consulting the relevant literature at home and abroad, the author has summarized the chemical constituents, quality evaluation, pharmacological action of Bixie, hoping to provide a reference for further research, development and utilization of Bixie.

Characterization of the Dioscorin Gene Family in Dioscorea alata Reveals a Role in Tuber Development and Environmental Response.

Dioscorin is one of the major soluble proteins in yam tubers. Unlike other well-known plant storage proteins, such as patatin and sporamin, dioscorin is argued for its function as storage proteins, and the molecular mechanisms underlying its expressional complexity are little understood. In this study, we isolated five dioscorin genes from Dioscorea alata L., comprising three class A (Da-dio1, -3 and -4) and two class B (Da-dio2 and -5) isoforms. Expressions of all dioscorin genes gradually decreased in mother tubers during yam sprouting and regrowth. On the other hand, all dioscorin genes accumulated transcripts progressively with tuber development in new tubers, with Da-dio5 being the most prominent isoform. In yam leaves, the expressions of Da-dio5 were up-regulated by the treatments of five phytohormones (gibberellic acid, salicylic acid, indole-3-acetic acid, abscisic acid, and ethylene), and three abiotic stresses (high-temperature, low-temperature and drought). To further elucidate the regulatory mechanisms of Da-dio5 expressions, transgenic Arabidopsis plants harboring the Da-dio5 promoter-ß-glucuronidase (GUS) fusion were generated. GUS staining showed that expressions of the Da-dio5 promoter were detected mainly in the shoot apical meristem (SAM) and hypocotyls, and enhanced by the treatments of the five hormones, and the three abiotic stresses mentioned above. These results suggest diverse roles of Da-dio5 in yam sprouting, regrowth, and tuberization, as well as in response to enviromental cues.

Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers.

Yams (Dioscorea sp.) are staple food crops for millions of people in tropical and subtropical regions. Dioscorea alata, also known as greater yam, is one of the major cultivated species and most widely distributed throughout the tropics. Despite its economic and cultural importance, very little is known about its origin, diversity and genetics. As a consequence, breeding efforts for resistance to its main disease, anthracnose, have been fairly limited. The objective of this study was to contribute to the understanding of D. alata genetic diversity by genotyping 384 accessions from different geographical regions (South Pacific, Asia, Africa and the Caribbean), using 24 microsatellite markers. Diversity structuration was assessed via Principal Coordinate Analysis, UPGMA analysis and the Bayesian approach implemented in STRUCTURE. Our results revealed the existence of a wide genetic diversity and a significant structuring associated with geographic origin, ploidy levels and morpho-agronomic characteristics. Seventeen major groups of genetically close cultivars have been identified, including eleven groups of diploid cultivars, four groups of triploids and two groups of tetraploids. STRUCTURE revealed the existence of six populations in the diploid genetic pool and a few admixed cultivars. These results will be very useful for rationalizing D. alata genetic resources in breeding programs across different regions and for improving germplasm conservation methods.

A single molecular marker to distinguish between species of Dioscorea.

Yams are species of the genus Dioscorea (family Dioscoreaceae), which consists of approximately 630 species. The majority of the world production of yams occurs in Africa with 58.8 million t annually, but they are also produced in the Americas and Asia. The saponins in yams have been reported to possess various properties to improve health. The tuber and aerial parts of various species often share morphological similarities, which can cause problems in the proper identification of sample material. For example, the rootstocks and aerial parts of Dioscorea villosa L. share similarities with Dioscorea polystachia Turcz. Dioscorea bulbifera L. may be mistaken for Dioscorea alata L. owing to similar morphologies. Various molecular analyses have been published to help with the identification of species and varieties within the genus Dioscorea. The multi-loci or single-locus analysis has resulted in varying success, some with only a limited discrimination rate. In the present study, a single nuclear genomic region, biparentally inherited, was analyzed for its usefulness as a molecular marker for species identification and discrimination between D. bulbifera, D. villosa, D. nipponica, D. alata, D. caucasica, and D. deltoidea samples. The results of this study show that the LFY genomic region can be useful as a molecular marker to distinguish between samples.

Diversification into novel habitats in the Africa clade of Dioscorea (Dioscoreaceae): erect habit and elephant's foot tubers.

BACKGROUND: Dioscorea is a widely distributed and highly diversified genus in tropical regions where it is represented by ten main clades, one of which diversified exclusively in Africa. In southern Africa it is characterised by a distinct group of species with a pachycaul or "elephant's foot" structure that is partially to fully exposed above the substrate. In contrast to African representatives of the genus from other clades, occurring mainly in forest or woodland, the pachycaul taxa and their southern African relatives occur in diverse habitats ranging from woodland to open vegetation. Here we investigate patterns of diversification in the African clade, time of transition from forest to more open habitat, and morphological traits associated with each habitat and evaluate if such transitions have led to modification of reproductive organs and mode of dispersal. RESULTS: The Africa clade originated in the Oligocene and comprises four subclades. The Dioscorea buchananii subclade (southeastern tropical Africa and South Africa) is sister to the East African subclade, which is respectively sister to the recently evolved sister South African (e. g., Cape and Pachycaul) subclades. The Cape and Pachycaul subclades diversified in the east of the Cape Peninsula in the mid Miocene, in an area with complex geomorphology and climate, where the fynbos, thicket, succulent karoo and forest biomes meet. CONCLUSIONS: Diversification out of forest is associated with major shifts in morphology of the perennial tuber (specifically an increase in size and orientation which presumably led them to become pachycaul) and rotation of stem (from twining to non-twining). The iconic elephant's foot morphology, observed in grasslands and thicket biomes, where its corky bark may offer protection against fire and herbivory, evolved since mid Miocene. A shift in pollination trait is observed within the forest, but entry into open habitat does not show association with reproductive morphology, except in the seed wing, which has switched from winged all round the seed margin to just at the base or at the apex of it, or has been even replaced by an elaiosome.

The chloroplast genome sequence of an important medicinal plant Dioscorea nipponica.

Dioscorea nipponica is an important medicinal plant belonging to Dioscoreaceae, a family which is vital for the evolution of monocotyledon. In the present study, the nucleotide sequence of the D. nipponica chloroplast genome was determined. It was an AT-rich (63.3%) chloroplast genome with 152,946 bp in length, containing a pair of 23,113 bp inverted repeats, which were separated by a large and a small single copy region of 83,557 bp and 23,064 bp in length, respectively. It encodes 120 unique genes, including 89 protein-coding genes, 27 tRNA genes and 4 rRNA genes. The predicted gene-coding regions covered 58.7% of the genome sequences. Ten genes contained one intron, while two genes had two introns. Phylogenetic analyses showed the present chloroplast genome can be used as a potential supper barcode to distinguish D. nipponica from its closely related species. Furthermore, the chloroplast genome provides a molecular base for the next investigation on this important medicinal species.

The complete chloroplast genome sequence of Dioscorea zingiberensis (Dioscoreceae).

Dioscorea zingiberensis (Dioscoreceae) is an important medicinal plant endemic to China. Here, its chloroplast genome sequence is reconstructed from the whole-genome Illumina sequencing data. The circular genome is 153,970 bp in length, and comprises a pair of inverted repeat (IR) regions of 25,491 bp each, a large single-copy (LSC) region of 83,950 bp and a small single-copy (SSC) region of 19,038 bp. The chloroplast genome contains 132 genes, including 86 protein-coding genes (79 PCG species), 8 ribosomal RNA genes (four rRNA species) and 38 transfer RNA genes (30 tRNA species). Out of these genes, 10 harbor a single intron, and 7 contain a couple of introns. The overall A + T content of the whole genome is 62.8%, while the corresponding values of the LSC, SSC and IR regions are 64.9%, 68.8% and 57.0%, respectively.

Distribution, management and diversity of the endangered Amerindian yam (Dioscorea trifida L.).

The objective of this study was to verify the occurrence of Dioscorea trifida in Brazil and to obtain information concerning its distribution, management and diversity. Farmers from 21 communities were interviewed in the states of São Paulo, Santa Catarina and Mato Grosso. During the visits, semi-structured interviews were conducted to collect socio-economic, management and diversity data for this crop. Fifty-one collected accessions, plus two accessions obtained at local markets of Amazonas, were characterized using 12 morphological traits. Most the interviewed farmers were men (75%) with a mean age of 59.5 years. Just a few young people and labor force were available for agricultural activities, with an average of only three individuals per farm. Most farmers (56%) grew only one variety of D. trifida, although 44% had more than one variety in their fields, which aims to provide greater assurance at harvest. Many popular names were observed for D. trifida, and cará roxo (purple yam) was the name most used by farmers (43.4%). Characters referring to the tuber, such as skin and flesh color, were most relevant for the distinction of the accessions. The results of this study may collaborate to develop strategies for conservation, both ex situ and in situ, within the view of on farm conservation.

Distribution, management and diversity of the endangered Amerindian yam (Dioscorea trifida L.) / Distribuição, manejo e diversidade da espécie ameaçada de inhame ameríndio (Dioscorea trifida L.)

The objective of this study was to verify the occurrence of Dioscorea trifida in Brazil and to obtain information concerning its distribution, management and diversity. Farmers from 21 communities were interviewed in the states of São Paulo, Santa Catarina and Mato Grosso. During the visits, semi-structured interviews were conducted to collect socio-economic, management and diversity data for this crop. Fifty-one collected accessions, plus two accessions obtained at local markets of Amazonas, were characterized using 12 morphological traits. Most the interviewed farmers were men (75%) with a mean age of 59.5 years. Just a few young people and labor force were available for agricultural activities, with an average of only three individuals per farm. Most farmers (56%) grew only one variety of D. trifida, although 44% had more than one variety in their fields, which aims to provide greater assurance at harvest. Many popular names were observed for D. trifida, and cará roxo (purple yam) was the name most used by farmers (43.4%). Characters referring to the tuber, such as skin and flesh color, were most relevant for the distinction of the accessions. The results of this study may collaborate to develop strategies for conservation, both ex situ and in situ, within the view of on farm conservation.

O objetivo deste trabalho foi verificar a ocorrência de Dioscorea trifida no Brasil e obter informações a respeito da sua distribuição, manejo e diversidade. Para tanto, foram visitados e entrevistados agricultores de 21 comunidades, nos Estados de São Paulo, Santa Catarina, Mato Grosso. Durante as visitas, foram realizadas entrevistas semi-estruturadas visando obter dados sócioeconômicos, de manejo e diversidade da cultura. Cinquenta e um acessos, além de dois acessos adquiridos em feiras no Estado do Amazonas, foram caracterizados por meio de 12 descritores morfológicos. A maioria dos entrevistados era homem (75%) com média de idade de 59,5 anos. Observou-se um número reduzido de jovens e mão de obra disponível para as atividades agrícolas, cerca de três indivíduos por roça. A maior parte dos agricultores (56%) cultiva apenas uma variedade de D. trifida, embora 44% tenham declarado o cultivo de mais de uma variedade, procedimento que visa dar maior garantia de colheita. Vários nomes populares foram observados para D. trifida, sendo cará roxo, a denominação mais utilizada pelos agricultores (43,4%). Os caracteres referentes às túberas, como cor da casca e da polpa, foram os mais relevantes para a distinção dos acessos. Os resultados obtidos poderão colaborar para elaborar estratégias de conservação, tanto ex situ como in situ, dentro da visão de conservação on farm.

[Studies on genetic relationship of Dioscorea].

Based on the results of the morphologic studies on genus Dioscorea, the paper summarized the entire chemical constituent that isolated from this genus and analyzed it with the methods of chemotaxonomy. The rules of the chemical constituent and pharmacodynamic effects were analyzed. Seventeen species which belong to Sect. Stenophora Uline of Dioscorea contain steroidal sapogenin. Other species with different main components such as polysaccharide and tannin have have different effects. This chemotaxonomic view point will conduce to establish a phylogeny of the genus Dioscorea.

Distribution, management and diversity of yam local varieties in Brazil: a study on Dioscorea alata L.

Widely spread in the tropics, yams were introduced into Brazil during the colonial period and are currently grown throughout the country. Despite its importance as a pharmacological and food source, there is a lack of studies describing how and where this tuber is grown in Brazil. The aim of this study was to provide an overview of the cultivation and distribution of Dioscorea alata in different Brazilian regions. A total of 63 farmers were visited in different municipalities and communities in four regions in the country: South, Southeast, Northeast and Midwest. Semi-structured interviews were conducted to collect socio-economic, use, management and diversity data for this crop. The majority of interviewers were men, married, with children, using retirement benefits and agriculture as income and family labour as the main support in the yam cultivation. A wide distribution of this species was found, with the occurrence of D. alata in the four sampled regions. A variety of vernacular names for this species was collected, differing according to the region where it is cultivated. Most farmers cultivate yams in fields, however an increased usage of home gardens for the cultivation of this tuber was found. Also, most farmers cultivate yams in association with other crops in areas of different sizes and slash and burn practices, although mostly disappearing, are still being used by many farmers. The results of this study provide more concrete data on the distribution and diversity of this important crop.

Application of anatomy and HPTLC in characterizing species of Dioscorea (Dioscoreaceae).

The edible tubers from different species of Dioscorea are a major source of food and nutrition for millions of people. Some of the species are medicinally important but others are toxic. The genus consists of about 630 species of almost wholly dioecious plants, many of them poorly characterized. The taxonomy of Dioscorea is confusing and identification of the species is generally problematic. There are no adequate anatomical studies available for most of the species. This study is aimed to fill this gap and provides a detailed investigation of the anatomy and micro-morphology of the rhizomes and tubers of five different species of Dioscorea, namely D. balcanica, D. bulbifera, D. polystachya, D. rotundata and D. villosa. The primary features that can help in distinguishing the species include the nature of periderm, presence or absence of pericyclic sclereids, lignification in the phloem, types of calcium oxalate crystals and features of starch grains. The descriptions are supported with images of bright-field and scanning electron microscopy for better understanding of these species. The diagnostic key of anatomical features included in this paper can help distinguish the investigated species unambiguously. Additionally, HPTLC analyses of authentic and commercial samples of the five species are described.

Extraction of total DNA and optimization of the RAPD reaction system in Dioscorea opposita Thunb.

Dioscorea opposita Thunb. has been used as health food and herbal medicinal ingredients in traditional Chinese medicine. In this study, the total DNA of D. opposita Thunb. was extracted using an improved cetyltrimethylammonium bromide (CTAB) method, and the extracted DNA was further used for random amplified polymorphic DNA (RAPD) reaction system by design of the L16 (4(4)) orthogonal diagram. The results showed that the improved CTAB method can be used to isolate high-quality and high-concentration DNA, and the optimized protocol can overcome the instability of RAPD reaction system. The knowledge stated here can be used to study the genetic diversity of D. opposita Thunb.

Characterization of steroidal saponins from Dioscorea villosa and D. cayenensis using ultrahigh performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry.

Yam (Dioscorea spp.) is an important edible tuber plant used for medicinal purposes to promote health and longevity in Chinese tradition. Steroidal saponins were reported to be the major physiologically active constituents in yams. In this current work, the structural characteristics of steroidal saponins in methanolic extracts from dried rhizomes of two Dioscorea species (D. villosa L. and D. cayenensis Lam.) and dietary supplements have been identified and analyzed using UHPLC/QTOF-MS in both negative and positive ion modes. The fragmentation patterns of reference standards were determined and the steroidal saponins in the extracts were identified or tentatively characterized from their retention times and mass spectra. The fragments produced by collision-induced dissociation (CID) revealed the characteristic cleavage of glycosidic bonds, and the fragmentation pattern provided structural information about the sugars. Twenty-one saponins, including four tentatively identified compounds, were detected in the crude extracts of two Dioscorea species. These saponins can be used to distinguish D. villosa from D. cayenensis. For example, asperin and gracillin are found only in D. cayenensis, and dioscoreavilloside A and B and parvifloside are only found in D. villosa. This can be used to determine the presence or absence of D. villosa in commercial products, which may help determine the spiking of plant material, and/or prevent the use of potentially mislabeled or misidentified "Dioscorea" material. The analytical method also provided an alternative, fast method for quality control of Dioscorea species in dietary supplements. Principal component analysis showed that Dioscorea species and commercial products were easily distinguished. From this a partial least squares model was constructed to determine what species are in different products.

Genetic structure and diversity in the Dioscorea cayenensis/D. rotundata complex revealed by morphological and isozyme markers.

Of the 600 known yam species, only 10 are utilized as food, and the Dioscorea cayenensis/D. rotundata species complex is among the most cultivated. In Brazil, these species are commercially cultivated in the northeast region and are cultivated in the south and southeast regions as subsistence crops by traditional agriculturists. This study aimed to evaluate the genetic diversity of 21 local varieties of D. cayenensis and 2 D. rotundata accessions using 7 isozymic loci and 24 morphological markers, and to investigate the diversity distribution in different levels of organization, such as swidden fields and communities of Vale do Ribeira. Cluster analyses for both the isozymic and morphological data separated the 2 D. rotundata accessions from the D. cayenensis accessions from Vale do Ribeira. The analysis with morphological characteristics showed the presence of 2 subgroups (Iguape and Cananéia) within group I, which included all of the local varieties from Vale do Ribeira; this result may indicate the influence of the cultural units on the morphological variation. Molecular analysis of variance indicated that most of the isozymic variability was concentrated among swiddens within communities (42.5%) and within communities (40.3%). Most of the morphological variability was also concentrated among swidden fields within communities (44.8%). The correlation between geographic and genetic distances indicated that neither morphological (r = 0.17) nor isozymic diversity (r = -0.15) is structured in space. Thus, the traditional agriculturists of Vale do Ribeira maintain and manage a great diversity of D. cayenensis varieties in their communities.

Distribution, management and diversity of yam local varieties in Brazil: a study on Dioscorea alata L. / Distribuição, manejo e diversidade de variedades locais de inhame no Brasil: um estudo em Dioscorea alata L.

Widely spread in the tropics, yams were introduced into Brazil during the colonial period and are currently grown throughout the country. Despite its importance as a pharmacological and food source, there is a lack of studies describing how and where this tuber is grown in Brazil. The aim of this study was to provide an overview of the cultivation and distribution of Dioscorea alata in different Brazilian regions. A total of 63 farmers were visited in different municipalities and communities in four regions in the country: South, Southeast, Northeast and Midwest. Semi-structured interviews were conducted to collect socio-economic, use, management and diversity data for this crop. The majority of interviewers were men, married, with children, using retirement benefits and agriculture as income and family labour as the main support in the yam cultivation. A wide distribution of this species was found, with the occurrence of D. alata in the four sampled regions. A variety of vernacular names for this species was collected, differing according to the region where it is cultivated. Most farmers cultivate yams in fields, however an increased usage of home gardens for the cultivation of this tuber was found. Also, most farmers cultivate yams in association with other crops in areas of different sizes and slash and burn practices, although mostly disappearing, are still being used by many farmers. The results of this study provide more concrete data on the distribution and diversity of this important crop.

Amplamente difundido nos trópicos, o inhame entrou no Brasil na época da colonização e atualmente é cultivado em todo o país. Apesar de sua importância como cultura alimentícia e farmacológica, são raros os estudos que identifiquem como e onde esse tubérculo está sendo cultivado no Brasil. Este estudo teve como objetivo apresentar um panorama do cultivo e distribuição da espécie Dioscorea alata L. em diversas regiões do Brasil. Para tanto, foram visitados 63 agricultores em diferentes municípios, distribuídos entre o Sul, Sudeste, Nordeste e Centro-Oeste do país. Foram realizadas entrevistas semi-estruturadas, nas quais foram levantados dados socioeconômicos, bem como sobre o uso, manejo e diversidade dessa espécie. A maioria dos entrevistados eram homens casados, com filhos, que possuíam aposentadoria e a agricultura como principais fontes de renda. Constatou-se que a mão-de-obra familiar está bastante envolvida com o cultivo de inhame. Uma ampla distribuição da espécie foi observada, com a ocorrência de D. alata nas quatro regiões amostradas. Grande diversidade de nomes populares foi observada para a espécie neste estudo, com diferenças na nomenclatura popular em função das diferentes regiões onde a mesma é cultivada. A maioria dos agricultores cultiva inhame em roças, no entanto a importância dos quintais foi observada em vários municípios. Verificou-se também que a maioria dos entrevistados cultiva o inhame em consorciação com outras culturas e que a prática do pousio ainda é utilizada por muitos dos agricultores. Os resultados deste estudo permitiram gerar dados mais concretos sobre a distribuição e diversidade desta importante cultura.

Development of polymorphic microsatellite markers for Dioscorea zingiberensis and cross-amplification in other Dioscorea species.

Dioscorea zingiberensis C.H. Wright (Dioscoreaceae) is an endemic species in central and southwestern China. In order to study the genetic diversity and population structure of this species, 19 novel polymorphic microsatellite loci were developed using a dual-suppression PCR technique. The number of alleles per locus ranged from 3 to 21, with an average of 9.53. All the markers showed high transferability in cross-species amplification in other species of sect. Stenophora.