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Abstract Amazonia, one of the largest and most biodiverse ecosystems on Earth, is a significant yet less-known arena for ancient plant domestication. Here, we traced the origins of cupuaçu (Theobroma grandiflorum), an Amazonian tree crop closely related to cacao (T. cacao), cherished for its flavorful seed-pulp, by employing an extensive genomic analysis based on data from four sites in Brazil. Our results indicate that cupuaçu is a domesticated variant of its wild relative, cupuí (T. subincanum), probably originating from the Middle-Upper Rio Negro basin. A first phase of domestication is observed through a genetic bottleneck that we estimated to have occurred 5000–8000 years before the present. Moreover, we found further reductions in genetic diversity that we estimated to have occurred during the modern era. This is consistent with a second phase of domestication that was accompanied by an increase in the geographic distribution of cupuaçu over the last two centuries. Unraveling cupuaçu’s origins adds it to the roster of plants domesticated by Amazonian indigenous people in the early to mid-Holocene. Our results suggest that Amazonia’s current patterns of genetic diversity and distribution of domesticated plants were influenced by both pre-Columbian and modern histories.

Sugarcane (Saccharum spp.) is an important crop for sugar and bioethanol production worldwide. To maintain and increase sugarcane yields in marginal areas, the use of nitrogen (N) fertilizers is essential, but N overuse may result in the leaching of reactive N to the natural environment. Despite the importance of N in sugarcane production, little is known about the molecular mechanisms involved in N homeostasis in this crop, particularly regarding ammonium (NH4+), the sugarcane’s preferred source of N. Here, using a sugarcane bacterial artificial chromosome (BAC) library and a series of in silico analyses, we identified an AMMONIUM TRANSPORTER (AMT) from the AMT2 subfamily, sugarcane AMMONIUM TRANSPORTER 3;3 (ScAMT3;3), which is constitutively and highly expressed in young and mature leaves. To characterize its biochemical function, we ectopically expressed ScAMT3;3 in heterologous systems (Saccharomyces cerevisiae and Arabidopsis thaliana). The complementation of triple mep mutant yeast demonstrated that ScAMT3;3 is functional for NH3/H+ cotransport at high availability of NH4+ and under physiological pH conditions. The ectopic expression of ScAMT3;3 in the Arabidopsis quadruple AMT knockout mutant restored the transport capacity of 15N–NH4+ in roots and plant growth under specific N availability conditions, confirming the role of ScAMT3;3 in NH4+ transport in planta. Our results indicate that ScAMT3;3 belongs to the low-affinity transport system (Km 270.9 µM; Vmax 209.3 µmol g−1 root DW h−1). We were able to infer that ScAMT3;3 plays a presumed role in NH4+ source–sink remobilization in the shoots via phloem loading. These findings help to shed light on the functionality of a novel AMT2-type protein and provide bases for future research focusing on the improvement of sugarcane yield and N use efficiency.

Drought is a major constraint to sugarcane (Saccharum spp.) production and improving the water use efficiency (WUE) is a critical trait for the sustainability of this bioenergy crop. The molecular mechanism underlying WUE remains underexplored in sugarcane. Here, we investigated the drought-triggered physiological and transcriptional responses of two sugarcane cultivars contrasting for drought tolerance, ‘IACSP97-7065’ (sensitive) and ‘IACSP94-2094’ (tolerant). After 21 days without irrigation (DWI), only ‘IACSP94-2094’ exhibited superior WUE and instantaneous carboxylation efficiency, with the net CO2 assimilation being less impacted when compared with ‘IACSP97-7065’. RNA-seq of sugarcane leaves at 21 DWI revealed a total of 1,585 differentially expressed genes (DEGs) for both genotypes, among which ‘IACSP94-2094’ showed 617 (38.9%) exclusive transcripts (212 up- and 405 down-regulated). Functional enrichment analyses of these unique DEGs revealed several relevant biological processes, such as photosynthesis, transcription factors, signal transduction, solute transport, and redox homeostasis. The better drought-responsiveness of ‘IACSP94-2094’ suggested signaling cascades that foster transcriptional regulation of genes implicated in the Calvin cycle and transport of water and carbon dioxide, which are expected to support the high WUE and carboxylation efficiency observed for this genotype under water deficit. Moreover, the robust antioxidant system of the drought-tolerant genotype might serve as a molecular shield against the drought-associated overproduction of reactive oxygen species. This study provides relevant data that may be used to develop novel strategies for sugarcane breeding programs and to understand the genetic basis of drought tolerance and WUE improvement of sugarcane.

Abstract Drought is the most detrimental abiotic stress to sugarcane production. Nevertheless, transcriptomic analyses remain scarce for field-grown plants. Here we performed comparative transcriptional profiling of two contrasting sugarcane genotypes, ‘IACSP97-7065’ (drought-sensitive) and ‘IACSP94-2094’ (drought-tolerant) grown in a drought-prone environment. Physiological parameters and expression profiles were analyzed at 42 (May) and 117 (August) days after the last rainfall. The first sampling was done under mild drought (soil water potential of −60 kPa), while the second one was under severe drought (soil water potential of −75 kPa). Microarray analysis revealed a total of 622 differentially expressed genes in both sugarcane genotypes under mild and severe drought stress, uncovering about 250 exclusive transcripts to ‘IACSP94-2094’ involved in oxidoreductase activity, transcriptional regulation, metabolism of amino acids, and translation. Interestingly, the enhanced antioxidant system of ‘IACSP94-2094’ may protect photosystem II from oxidative damage, which partially ensures stable photochemical activity even after 117 days of water shortage. Moreover, the tolerant genotype shows a more extensive set of responsive transcription factors, promoting the fine-tuning of drought-related molecular pathways. These results help elucidate the intrinsic molecular mechanisms of a drought-tolerant sugarcane genotype to cope with ever-changing environments, including prolonged water deficit, and may be useful for plant breeding programs.

Abstract Tomato production is influenced by shoot branching, which is controlled by different hormones. Here we produced tomato plants overexpressing the cytokinin-deactivating gene CYTOKININ OXYDASE 2 (CKX2). CKX2-overexpressing (CKX2-OE) plants showed an excessive growth of axillary shoots, the opposite phenotype expected for plants with reduced cytokinin content, as evidenced by LC-MS analysis and ARR5-GUS staining. The TCP transcription factor SlBRC1b was downregulated in the axillary buds of CKX2-OE and its excessive branching was dependent on a functional version of the GRAS-family gene LATERAL SUPPRESSOR (LS). Grafting experiments indicated that increased branching in CKX2-OE plants is unlikely to be mediated by root-derived signals. Crossing CKX2-OE plants with transgenic antisense plants for the strigolactone biosynthesis gene CAROTENOID CLEAVAGE DIOXYGENASE (CCD7-AS) produced an additive phenotype, indicating independent effects of cytokinin and strigolactones on increased branching. On the other hand, CKX2-OE plants showed reduced polar auxin transport and their bud outgrowth was reduced when combined with auxin mutants. Accordingly, CKX2-OE basal buds did not respond to auxin applied in the decapitated apex. Our results suggest that tomato shoot branching depends on a fine-tuning of different hormonal balances and that perturbations in the auxin status could compensate for the reduced cytokinin levels in CKX2-OE plants.

AMMONIUM TRANSPORTER/METHYLAMMONIUM PERMEASE/RHESUS (AMT) family members transport ammonium across membranes in all life domains. Plant AMTs can be categorized into AMT1 and AMT2 subfamilies. Functional studies of AMTs, particularly AMT1-type, have been conducted using model plants but little is known about the function of AMTs from crops. Sugarcane (Saccharum spp.) is a major bioenergy crop that requires heavy nitrogen fertilization but depends on a low carbon-footprint for competitive sustainability. Here, we identified and functionally characterized sugarcane ScAMT2;1 by complementing ammonium uptake-defective mutants of Saccharomyces cerevisiae and Arabidopsis thaliana. Reporter gene driven by the ScAMT2;1 promoter in A. thaliana revealed preferential expression in the shoot vasculature and root endodermis/pericycle according to nitrogen availability and source. Arabidopsis quadruple mutant plants expressing ScAMT2;1 driven by the CaMV35S promoter or by a sugarcane endogenous promoter produced significantly more biomass than mutant plants when grown in NH4+ and showed more 15N-ammonium uptake by roots and nitrogen translocation to shoots. In A. thaliana, ScAMT2;1 displayed a Km of 90.17 µM and Vmax of 338.99 µmoles h-1 g-1 root DW. Altogether, our results suggest that ScAMT2;1 is a functional high-affinity ammonium transporter that might contribute to ammonium uptake and presumably to root-to-shoot translocation under high NH4+ conditions.

Abstract Background Plant pathogenesis related-1 (PR-1) proteins belong to the CAP superfamily and have been characterized as markers of induced defense against pathogens. Moniliophthora perniciosa and Moniliophthora roreri are hemibiotrophic fungi that respectively cause the witches’ broom disease and frosty pod rot in Theobroma cacao. Interestingly, a large number of plant PR-1-like genes are present in the genomes of both species and many are up-regulated during the biotrophic interaction. In this study, we investigated the evolution of PR-1 proteins from 22 genomes of Moniliophthora isolates and 16 other Agaricales species, performing genomic investigation, phylogenetic reconstruction, positive selection search and gene expression analysis. Results Phylogenetic analysis revealed conserved PR-1 genes (PR-1a, b, d, j), shared by many Agaricales saprotrophic species, that have diversified in new PR-1 genes putatively related to pathogenicity in Moniliophthora (PR-1f, g, h, i), as well as in recent specialization cases within M. perniciosa biotypes (PR-1c, k, l) and M. roreri (PR-1n). PR-1 families in Moniliophthora with higher evolutionary rates exhibit induced expression in the biotrophic interaction and positive selection clues, supporting the hypothesis that these proteins accumulated adaptive changes in response to host–pathogen arms race. Furthermore, although previous work showed that MpPR-1 can detoxify plant antifungal compounds in yeast, we found that in the presence of eugenol M. perniciosa differentially expresses only MpPR-1e, k, d, of which two are not linked to pathogenicity, suggesting that detoxification might not be the main function of most MpPR-1. Conclusions Based on analyses of genomic and expression data, we provided evidence that the evolution of PR-1 in Moniliophthora was adaptive and potentially related to the emergence of the parasitic lifestyle in this genus. Additionally, we also discuss how fungal PR-1 proteins could have adapted from basal conserved functions to possible roles in fungal pathogenesis.

The interaction between Metarhizium spp. and plant roots may induce host plant growth and help control below- and above-ground pests and diseases. We conducted in vivo and in vitro bioassays using native Brazilian isolates of Metarhizium robertsii (ESALQ 1635), M. humberi (ESALQ 1638), and M. anisopliae (ESALQ 1669) to better understand the possible mechanisms related to plant growth promotion traits and colonization of the root system in the model pot-grown tomato (Solanum lycopersicum L.) miniature cultivar “Micro-Tom.” In vivo trials revealed that M. robertsii (ESALQ 1635) or M. humberi (ESALQ 1638) inoculated in tomato seedlings improved vegetative and reproductive traits. Inoculation with M. robertsii yielded taller plants, longer roots, and more shoot and root dry mass than M. humberi. The number of flowers and the fresh weight of fruits was significantly increased by M. robertsii and M. humberi inoculation, in relation to uninoculated control plants. Both fungal species endophytically colonized all tomato tissues within 30 days of inoculation. Plants inoculated with either M. robertsii or M. humberi increased auxin-induced GUS expression in the roots for up to 30 days after inoculation, confirming that Metarhizium induces auxin-regulated gene expression. We also explored the production of key compounds including enzymes, hormones, and metabolites involved in plant growth promotion. The three Metarhizium species grown with or without exogenous tryptophan were able to produce indole-3-acetic acid (IAA) at different titers. All Metarhizium isolates produced phosphatases, phytases, siderophores, and chitinases. Of particular importance, the M. robertsii and M. humberi isolates exhibited similar in vitro biochemical profiles, whereas M. anisopliae and Trichoderma harzianum isolates demonstrated distinct traits from the others. Taken together, we argue that the M. robertsii isolate is more efficient than the M. humberi isolate to endophytically colonize tomato plants resulting in improved growth. However, M. humberi (ESALQ 1638) yielded a slightly better production of some metabolites in vitro. Thus, we propose that the isolates of M. robertsii and M. humberi could be explored as complementary plant growth promoters.

The commercial release of genetically modified organisms (GMO) requires a prior environmental and human/animal health risk assessment. In Brazil, the National Biotechnology Technical Commission (CTNBio) requires a survey of the area of natural occurrence of wild relatives of the GMO in the Brazilian ecosystems to evaluate the possibility of introgressive hybridization between sexually compatible species. Modern sugarcane cultivars, the focus of this study, derive from a series of hybridization and backcrossing events among Saccharum species. The so-called “Saccharum broad sense” group includes around 40 species from a few genera, including Erianthus, found in various tropical regions, particularly South-Eastern Asia. In Brazil, three native species, originally considered to belong to Erianthus, were reclassified as S. angustifolium (Nees) Trin., S. asperum (Nees) Steud., and S. villosum Steud., based on inflorescence morphology. Thus, we have investigated the potential occurrence of gene flow among the Brazilian Saccharum native species and commercial hybrids as a requisite for GMO commercial release. A comprehensive survey was carried out to map the occurrence of the three native Saccharum species in Brazil, concluding that they are sympatric with sugarcane cultivation only from around 14°S southwards, which precludes most Northeastern sugarcane-producing states from undergoing introgression. Based on phenology, we concluded that the Brazilian Saccharum species are unable to outcross naturally with commercial sugarcane since the overlap between the flowering periods of sugarcane and the native species is limited. A phylogenomic reconstruction based on the full plastid genome sequence showed that the three native Saccharum species are the taxa closest to sugarcane in Brazil, being closer than introduced Erianthus or Miscanthus. A 2-year study on eight nutritional composition traits of the 20 main sugarcane cultivars cultivated in Brazil was carried out in six environments. The minimum and maximum values obtained were, in percent: moisture (62.6–82.5); sucrose (9.65–21.76); crude fiber (8.06–21.03); FDN (7.20–20.68); FDA (4.55–16.90); lipids (0.06–1.59); ash (0.08–2.67); and crude protein (0.18–1.18). Besides a considerable amount of genetic variation and plastic responses, many instances of genotype-by-environment interaction were detected.

Abstract Background Our main purpose was to evaluate the expression of plastic and evolved genes involved in ecological speciation in the noctuid moth Spodoptera frugiperda, the fall armyworm (FAW); and to demonstrate how host plants might influence lineage differentiation in this polyphagous insect. FAW is an important pest of several crops worldwide, and it is differentiated into host plant-related strains, corn (CS) and rice strains (RS). RNA-Seq and transcriptome characterization were applied to evaluate unbiased genetic expression differences in larvae from the two strains, fed on primary (corn) and alternative (rice) host plants. We consider that genes that are differently regulated by the same FAW strain, as a response to different hosts, are “plastic”. Otherwise, differences in gene expression between the two strains fed on the same host are considered constitutive differences. Results Individual performance parameters (larval and pupal weight) varied among conditions (strains vs. hosts). A total of 3657 contigs was related to plastic response, and 2395 contigs were differentially regulated in the two strains feeding on preferential and alternative hosts (constitutive contigs). Three molecular functions were present in all comparisons, both down- and up-regulated: oxidoreductase activity, metal-ion binding, and hydrolase activity. Conclusions Metabolization of foreign chemicals is among the key functions involved in the phenotypic variation of FAW strains. From an agricultural perspective, high plasticity in families of detoxifying genes indicates the capacity for a rapid response to control compounds such as insecticides.

Abstract Background Citrus breeding programs have many limitations associated with the species biology and physiology, requiring the incorporation of new biotechnological tools to provide new breeding possibilities. Diversity Arrays Technology (DArT) markers, combined with next-generation sequencing, have wide applicability in the construction of high-resolution genetic maps and in quantitative trait locus (QTL) mapping. This study aimed to construct an integrated genetic map using full-sib progeny derived from Murcott tangor and Pera sweet orange and DArTseq™ molecular markers and to perform QTL mapping of twelve fruit quality traits. A controlled Murcott x Pera crossing was conducted at the Citrus Germplasm Repository at the Sylvio Moreira Citrus Centre of the Agronomic Institute (IAC) located in Cordeirópolis, SP, in 1997. In 2012, 278 F1 individuals out of a family of 312 confirmed hybrid individuals were analyzed for fruit traits and genotyped using the DArTseq markers. Using OneMap software to obtain the integrated genetic map, we considered only the DArT loci that showed no segregation deviation. The likelihood ratio and the genomic information from the available Citrus sinensis L. Osbeck genome were used to determine the linkage groups (LGs). Results The resulting integrated map contained 661 markers in 13 LGs, with a genomic coverage of 2,774 cM and a mean density of 0.23 markers/cM. The groups were assigned to the nine Citrus haploid chromosomes; however, some of the chromosomes were represented by two LGs due the lack of information for a single integration, as in cases where markers segregated in a 3:1 fashion. A total of 19 QTLs were identified through composite interval mapping (CIM) of the 12 analyzed fruit characteristics: fruit diameter (cm), height (cm), height/diameter ratio, weight (g), rind thickness (cm), segments per fruit, total soluble solids (TSS, %), total titratable acidity (TTA, %), juice content (%), number of seeds, TSS/TTA ratio and number of fruits per box. The genomic sequence (pseudochromosomes) of C. sinensis was compared to the genetic map, and synteny was clearly identified. Further analysis of the map regions with the highest LOD scores enabled the identification of putative genes that could be associated with the fruit quality characteristics. Conclusion An integrated linkage map of Murcott tangor and Pera sweet orange using DArTseq™ molecular markers was established and it was useful to perform QTL mapping of twelve fruit quality traits. The next generation sequences data allowed the comparison between the linkage map and the genomic sequence (pseudochromosomes) of C. sinensis and the identification of genes that may be responsible for phenotypic traits in Citrus. The obtained linkage map was used to assign sequences that had not been previously assigned to a position in the reference genome.

A sugarcane gene encoding a dirigent-jacalin, ShDJ, was induced under drought stress. To elucidate its biological function, we integrated a ShDJ-overexpression construction into the rice Nipponbare genome via Agrobacterium-mediated transformation. Two transgenic lines with a single copy gene in T0 were selected and evaluated in both the T1 and T4 generations. Transgenic lines had drastically improved survival rate under water deficit conditions, at rates close to 100%, while WT did not survive. Besides, transgenic lines had improved biomass production and higher tillering under water deficit conditions compared with WT plants. Reduced pectin and hemicellulose contents were observed in transgenic lines compared with wild-type plants under both well-watered and water deficit conditions, whereas cellulose content was unchanged in line #17 and reduced in line #29 under conditions of low water availability. Changes in lignin content under water deficit were only observed in line #17. However, improvements in saccharification were found in both transgenic lines along with changes in the expression of OsNTS1/2 and OsMYB58/63 secondary cell wall biosynthesis genes. ShDJ-overexpression up-regulated the expression of the OsbZIP23, OsGRAS23, OsP5CS, and OsLea3 genes in rice stems under well-watered conditions. Taken together, our data suggest that ShDJ has the potential for improving drought tolerance, plant biomass accumulation, and saccharification efficiency.

We applied the ddRAD genotyping-by-sequencing technique to investigate the genetic distinctiveness of Brazilian populations of the noctuid moth Spodoptera frugiperda, the fall armyworm (FAW), and the role of host-plant association as a source of genetic diversification. By strain-genotyping all field-collected individuals we found that populations collected from corn were composed primarily of corn-strain individuals, while the population collected from rice was composed almost entirely of rice-strain individuals. Outlier analyses indicated 1,184 loci putatively under selection (ca. 15% of the total) related to 194 different Gene Ontologies (GOs); the most numerous GOs were nucleotide binding, ATP binding, metal-ion binding and nucleic-acid binding. The association analyses indicated 326 loci associated with the host plant, and 216 loci associated with the individual strain, including functions related to Bacillus thuringiensis and insecticide resistance. The genetic-structure analyses indicated a moderate level of differentiation among all populations, and lower genetic structure among populations collected exclusively from corn, which suggests that the population collected from rice has a strong influence on the overall genetic structure. Populations of S. frugiperda are structured partially due to the host plant, and pairs of populations using the same host plant are more genetically similar than pairs using different hosts. Loci putatively under selection are the main factors responsible for the genetic structure of these populations, which indicates that adaptive selection on important traits, including the response to control tactics, is acting in the genetic differentiation of FAW populations in Brazil.

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes (Vacuolar ATPase-A and Arginine kinase) based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet for T. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliver in planta-transcribed dsRNA to target insect genes. Tuta absoluta larvae that fed on leaves containing dsRNA of the target genes showed an ∼60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage by T. absoluta in these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

RNA silencing mechanisms are conserved throughout eukaryotic evolution, possibly due to their importance in viral resistance and other aspects of cell biology. Here, we explored the Citrus EST (CitEST) database in search of sequences related to the most important known genes involved in RNA silencing. Transcripts strongly matching Argonaute (AGO), Dicer-like (DCL), Hua enhancer (HEN), and RNA-dependent RNA Polymerase (RdRP) were found in many of the citrus libraries. The reads were clustered and quantified. This shows that post-transcriptional gene silencing apparatus is active in citrus. It seems plausible that a better understanding of the players of RNA silencing in Citrus spp. and related genera may help create new tools to defeat the viral diseases that affect the citrus industry. Functional analyses of these citrus genes would enable the pursuit of this hypothesis.

Plastid-related sequences, derived from putative nuclear or plastome genes, were searched in a large collection of expressed sequence tags (ESTs) and genomic sequences from the Citrus Biotechnology initiative in Brazil. The identified putative Citrus chloroplast gene sequences were compared to those from Arabidopsis, Eucalyptus and Pinus. Differential expression profiling for plastid-directed nuclear-encoded proteins and photosynthesis-related gene expression variation between Citrus sinensis and Citrus reticulata, when inoculated or not with Xylella fastidiosa, were also analyzed. Presumed Citrus plastome regions were more similar to Eucalyptus. Some putative genes appeared to be preferentially expressed in vegetative tissues (leaves and bark) or in reproductive organs (flowers and fruits). Genes preferentially expressed in fruit and flower may be associated with hypothetical physiological functions. Expression pattern clustering analysis suggested that photosynthesis- and carbon fixation-related genes appeared to be up- or down-regulated in a resistant or susceptible Citrus species after Xylella inoculation in comparison to non-infected controls, generating novel information which may be helpful to develop novel genetic manipulation strategies to control Citrus variegated chlorosis (CVC).

Plants not only evolve but also reduce oxygen in photosynthesis. An inevitable consequence of this normal process is the production of reactive oxygen species (ROS). Plants are adequately protected by the presence of multiple antioxidative enzymes in the cytosol and also in the different cell organelles such as chloroplasts, mitochondria, and peroxisomes. Traditionally, ROS were considered to be only a toxic byproduct of aerobic metabolism. However, recently it has become apparent that plants actively produce these molecules which may control many different physiological processes such as abiotic and biotic stress response, pathogen defense and systemic signaling. The search results using the Citrus Genome Program in Brazil (CitEST) for oxidative stress and the antioxidant enzyme system in Citrus Sinensis variety ‘Pera IAC’ indicated that the multiple ROS-scavenging enzymes were expressed throughout all citrus tissues. The analyses demonstrated the ubiquitous expression of metallothioneins, probably indicating a constitutive expression pattern. Oxalate oxidase has been identified as the most abundant expressed gene in developing fruits, which suggests a specific function in the ripening of citrus fruit. Moreover, infected leaves with Xylella fastidiosa and Leprosis citri showed a massive change in their ROS gene expression profile which may indicate that the suppression of ROS detoxifying mechanisms may be involved in the induction of the diseases.

Com objetivo de estudar diversidade genética e identificar marcadores associados à resistência ao míldio (Plasmopara viticola) e ao oídio (Uncinula necator), foram analisadas as cultivares de videira A 1976, CG 87746, CNPUV 154-27, Crimson Seedless, Gota de Ouro, Itália, Seyve Villard 12327 e Seyve Villard 12375. As análises de polimorfismo de comprimento de fragmento amplificado (AFLP) seguiram as etapas de digestão, ligação, pré-amplificação e amplificação. Efetuou-se a separação dos fragmentos amplificados em gel de 7% de poliacrilamida desnaturante (uréia 7M) e coloração com nitrato de prata. A similaridade foi estimada com base no coeficiente de Jaccard, e a agregação, por UPGMA. Foi gerada uma matriz de similaridade com bom ajustamento da agregação (r = 0,84). Os agrupamentos obtidos corresponderam à origem e classificação botânica das cultivares. Foram identificadas 15 marcas dissimilares associadas à resistência, sendo oito para míldio e sete para oídio.The grapevine cultivars A 1976, CG 87746, CNPUV 154-27, Crimson Seedless, Gota de Ouro, Itália, Seyve Villard 12327 and Seyve Villard 12375 were analyzed to establish the genetic relationship and to identify markers associated with resistance to downy mildew (Plasmopara viticola) and powdery mildew (Uncinula necator). The amplified fragment lenght polymorphism (AFLP) analysis comprise the steps of digestion, ligation, preamplification and amplification. The amplified fragments were separeted on a 7% denaturing polyacrylamide gel (7M urea) and silver stained. The similarity was estimated using Jaccard's coefficient and the clustering was estimated by UPGMA. A similarity matrix was generated with a good fit for aggregation (r = 0,84). The clusters corresponded to origin and botany classification of the cultivars. Fifteen markers were associated with resistance, eight for downy mildew and seven for powdery mildew.

There are two major in vivo collections of species of the genus Theobroma L. in Belém and Marituba, state of Pará, Brazil, and in both there are natural species, as well as natural and artificial interspecific hybrids. In order to organize a database of Brazilian Theobroma species, a description of the existing collections and detailed information about the interspecific hybrids, including an artificial key for their identification, are presented in this article.No Estado do Pará, Brasil, localizadas nas cidades de Belém e Marituba, existem duas coleções in vivo de espécies brasileiras do gênero Theobroma L.que abrigam, além das espécies naturais, híbridos inter-específicos obtidos natural ou artificialmente. Objetivando organizar uma base de dados sobre as espécies brasileiras do gênero Theobroma, descreve-se neste artigo as coleções existentes, com informação detalhada sobre os híbridos inter-específicos. Inclui-se chave artificial para identificação dos táxons verificados.

O objetivo deste trabalho foi selecionar descritores botânicoagronômicos quantitativos para caracterizar acessos de cupuaçuzeiro [Theobroma grandiflorum (Willd. ex Spreng.) Schum]. Foram avaliados 53 descritores associados a características de folha (14), de flor (18), de fruto (16), e descritores agronômicos (5). No descarte dos descritores, foi empregada a técnica multivariada de componentes principais, em duas etapas. Na primeira, a seleção aconteceu dentro de cada grupo. Em seguida, foi realizada análise conjunta para a seleção final. Três critérios foram adotados para descarte das variáveis. Foram descartados 34 descritores, representando redução de 64% dos inicialmente considerados. A lista mínima de descritores para o cupuaçuzeiro ficou assim composta: comprimento do pecíolo foliar, espessura do limbo foliar, largura do acume foliar, angulação das nervuras de base, comprimento do botão estriado, comprimento do pedúnculo floral, diâmetro do pedúnculo floral, diâmetro do ovário, número de óvulos, comprimento da lâmina da pétala, comprimento dos estaminóides, diâmetro transversal da semente, semente chocha, acidez, brix, pH, número de botões caídos ao solo, número de frutos imaturos caídos precocemente e número de vassouras-de-bruxa produzidas.The objective of this work was to select morphological and agronomic quantitative descriptors to characterize accessions of cupuaçuzeiro [Theobroma grandiflorum (Willd. ex Spreng.) Schum]. Fifty three descriptors were evaluated, including 14 from leaves, 18 from flowers, 16 from fruits, and 5 agronomic traits. To discard redundant or non-discriminating descriptors, a two step multivariate analysis of principal components was applied. The first phase included the selection of descriptors within each group of characteristics individually (leaf; flower; fruit; agronomic). Based on the descriptors selected in this first phase, a joined analysis of principal components for the final selection was done. Three criteria for variable exclusion were adopted. Thirty four descriptors were excluded, representing a reduction of 64%. A minimal list of descriptors for cupuaçuzeiro was proposed, including leaf length, leaf thickness, leaf apex width, leaf base vein angle, flower bud length, flower peduncle length, flower peduncle diameter, ovary girth, number of ovules, flower petal lamina length, staminode length, seed width, flat seeds, acidity, brix, pH, number of fallen flowers buds, number of abscised immature pods and number of witches-brooms.

Plant nutrient uptake is an active process, requiring energy to accumulate essential elements at higher levels in plant tissues than in the soil solution, while the presence of toxic metals or excess of nutrients requires mechanisms to modulate the accumulation of ions. Genes encoding ion transporters isolated from plants and yeast were used to identify sugarcane putative homologues in the sugarcane expressed sequence tag (SUCEST) database. Five cluster consensi with sequence homology to plant high-affinity phosphate transporter genes were identified. One cluster consensus allowed the prediction of a full-length protein containing 541 amino acids, with 81% amino acid identity to the Nicotiana tabacum NtPT1 gene, consisting of 12 membrane-spanning domains divided by a large hydrophilic charged region. Putative homologues to Arabidopsis thaliana micronutrient transporter genes were also detected in some of the SUCEST libraries. Iron uptake in grasses involves the release of the phytosiderophore mugeneic acid (MA) which chelate Fe3+ which is then absorbed by a specific transporter. Sugarcane expressed sequence tag (EST) homologous to genes coding for three enzymes of the mugeneic acid biosynthetic pathway [nicotianamine synthase; nicotianamine transferase; and putative mugeneic acid synthetase (ids3)] and a putative Fe3+-phytosiderophore transporter were detected. Seven sugarcane sequence clusters were identified with strong homology to members of the ZIP gene family (ZIP1, ZIP3, ZIP4, IRT1 and ZNT1), while four clusters homologous to ZIP2 and three to ZAT were found. Homologues to members of another gene family, Nramp, which code for broad-specificity transition metal transporters were also detected with constitutive expression. Partial transcripts homologous to genes encoding gamma-glutamylcysteine synthetase, glutathione synthetase, and phytochelatin synthase (responsible for biosynthesis of the metal chelator phytochelatin) and all four types of the major plant metal-chelator peptide metallothionein (MT) were identified: Type I MT being the most abundant (>1% of seed-library reads), followed by Type II which had a similar pattern of expression as that described for Arabidopsis MT. Identifying and understanding the expression of genes associated with nutrient uptake and metal tolerance could lead to the development of more nutrient-efficient sugarcane cultivars, or might allow the use of sugarcane as a hyper-accumulator plant for the restoration of contaminated areas in phytoremediation programs.A absorção de nutrientes pelas plantas é um processo ativo, requerendo energia para o acúmulo de nutrientes essenciais em níveis mais elevados nos tecidos vegetais do que na solução do solo, enquanto que a presença de metais tóxicos ou excesso de nutrientes requererem mecanismos para modular o acúmulo de íons. Genes que codificam transportadores de íons, isolados de plantas e de leveduras, foram usados para identificar homólogos presumíveis no banco de dados de seqüências expressas de cana-de-açúcar (SUCEST). Cinco consensos de grupos de seqüências com homologia a genes de transportadores de fosfato de alta afinidade foram identificados. O consenso de um dos grupos permitiu a predição da proteína completa, com 541 amino ácidos e 81% de identidade com o gene NtPT1 de Nicotiana tabacum, consistindo de 12 domínios transmembrana divididos por uma grande região hidrofílica. Homólogos presumíveis a genes transportadores de micronutrientes de Arabidopsis thaliana também foram detectados em algumas bibliotecas do SUCEST. A absorção de ferro em gramíneas envolve a liberação de um composto fito-sideróforo, ácido mugenêico (MA), que complexa com Fe3+, sendo então absorvido por um transportador específico. Seqüências expressas (EST, expressed sequence tag) de cana-de-açúcar homólogas aos genes que codificam as três enzimas da via de biossíntese do ácido mugenêico (nicotianamina sintase; nicotianamina transferase; e a sintetase presumível do ácido mugenêico ids3), além de um transportador presumível de Fe3+-fito-sideróforo foram também detectados. Sete grupos de seqüências de cana-de-açúcar foram identificados com grande homologia com os membros da família de genes ZIP (ZIP1, ZIP3, ZIP4, IRT1 e ZNT1), enquanto que quatro grupos apresentaram homologia com ZIP2 e três com ZAT. Seqüências homólogas aos membros de uma outra família de genes, Nramp, que codificam transportadores de metais de ampla espectro, foram também detectados com expressão constitutiva. Transcritos parciais homólogos aos genes que codificam g-glutamilcisteína sintetase, glutationa sintetase e fitoquelatina sintase (responsáveis pela biossíntese da proteína quelante de metais, fitoquelatina) e todos os quatro tipos do outro principal peptídeo quelante de metais em plantas, metalotioneína (MT), foram identificados: MT do tipo I sendo a mais abundante (> 1% das seqüências na biblioteca de sementes), seguido pela MT do tipo II, com padrão de expressão similar àquele descrito para MT de Arabidopsis. A identificação e a compreensão da expressão de genes associados com a absorção de nutrientes e tolerância a metais poderiam possibilitar o desenvolvimento de variedades de cana-de-açúcar mais eficientes nutricionalmente, ou permitiriam o uso da cana-de-açúcar como planta hiper-acumuladora para a restauração de área contaminadas em programas de fitorremediação.

Intestinal complications after laparoscopic cholecystectomy are rare and usually caused by direct injury sustained on trocar insertion. However, intestinal ischaemia has been reported as an unusual complication of the pneumoperitoneum. We describe a 55-years-old patient who underwent an uneventful laparoscopic cholecystectomy after an episode of acute cholecystitis. Initial recovery was complicated by development of increasing abdominal pain which led to open laparotomy on day 2. Gangrene of the distal ileum and right-sided colon was detected and small bowel resection with right colectomy and primary anastomosis was performed. Histological examination of the resected ileum showed features of venous hemorragic infarction and trombosis. In view of the proximity of the operation it is assumed that ileal ischaemia was precipitated by carbon dioxide pneumoperitoneum. Some studies have been demonstrated that, within 30 minutes of establishing a pneumoperitoneum at an intraabdominal pressure of 16 mmHg, cardiac output, blood flow in the superior mesenteric artery and portal vein decrease progressively. Carbon dioxide pneumoperitoneum may lead to mechanical compression of the splanchnic veins and mesenteric vasoconstriction as a result of carbon dioxide absortion. The distribution of the ischaemic segment of intestine is also unusual as the most precarious blood supply is traditionally at the splenic flexure of the colon. It has been suggested that intermittent decompression of the abdomen reduces the risk of mesenteric ischaemia during penumoperitoneum especially in patients with predisposing clinical features for arteriosclerosis intestinal. In present patient was observed intestinal venous infarction what remains unclear but we think the carbon dioxide pneumoperitoneum have been related to it.