RESUMEN
BACKGROUND: Sweetpotato (Ipomoea batatas (L.) Lam.), a hexaploid outcrossing crop, is an important staple and food security crop in developing countries in Africa and Asia. The availability of genomic resources for sweetpotato is in striking contrast to its importance for human nutrition. Previously existing sequence data were restricted to around 22,000 expressed sequence tag (EST) sequences and ~ 1,500 GenBank sequences. We have used 454 pyrosequencing to augment the available gene sequence information to enhance functional genomics and marker design for this plant species. RESULTS: Two quarter 454 pyrosequencing runs used two normalized cDNA collections from stems and leaves from drought-stressed sweetpotato clone Tanzania and yielded 524,209 reads, which were assembled together with 22,094 publically available expressed sequence tags into 31,685 sets of overlapping DNA segments and 34,733 unassembled sequences. Blastx comparisons with the UniRef100 database allowed annotation of 23,957 contigs and 15,342 singletons resulting in 24,657 putatively unique genes. Further, 27,119 sequences had no match to protein sequences of UniRef100database. On the basis of this gene index, we have identified 1,661 gene-based microsatellite sequences, of which 223 were selected for testing and 195 were successfully amplified in a test panel of 6 hexaploid (I. batatas) and 2 diploid (I. trifida) accessions. CONCLUSIONS: The sweetpotato gene index is a useful source for functionally annotated sweetpotato gene sequences that contains three times more gene sequence information for sweetpotato than previous EST assemblies. A searchable version of the gene index, including a blastn function, is available at http://www.cipotato.org/sweetpotato_gene_index.
Asunto(s)
Minería de Datos , Genes de Plantas/genética , Ipomoea batatas/genética , Repeticiones de Microsatélite/genética , Análisis de Secuencia de ADN/métodos , Temperatura , Secuencia de Bases , Mapeo Contig , Etiquetas de Secuencia Expresada , Anotación de Secuencia MolecularRESUMEN
Responses to prolonged drought and recovery from drought of two South American potato (Solanum tuberosum L. ssp. andigena (Juz & Buk) Hawkes) landraces, Sullu and Ccompis were compared under field conditions. Physiological and biomass measurements, yield analysis, the results of hybridisation to a potato microarray platform (44 000 probes) and metabolite profiling were used to characterise responses to water deficit. Drought affected shoot and root biomass negatively in Ccompis but not in Sullu, whereas both genotypes maintained tuber yield under water stress. Ccompis showed stronger reduction in maximum quantum yield under stress than Sullu, and less decrease in stomatal resistance. Genes associated with PSII functions were activated during recovery in Sullu only. Evidence for sucrose accumulation in Sullu only during maximum stress and recovery was observed, in addition to increases in cell wall biosynthesis. A depression in the abundance of plastid superoxide dismutase transcripts was observed under maximum stress in Ccompis. Both sucrose and the regulatory molecule trehalose accumulated in the leaves of Sullu only. In contrast, in Ccompis, the raffinose oligosaccharide family pathway was activated, whereas low levels of sucrose and minor stress-mediated changes in trehalose were observed. Proline, and expression of the associated genes, rose in both genotypes under drought, with a 3-fold higher increase in Sullu than in Ccompis. The results demonstrate the presence of distinct molecular and biochemical drought responses in the two potato landraces leading to yield maintenance but differential biomass accumulation in vegetative tissues.
RESUMEN
HI3 es una toxina que, en un trabajo anterior, fue aislada por nuestro grupo de investigación a partir del veneno del escorpión Hadruroides lunatus mediante cromatografía de intercambio iónico en CM-Sephadez C-25 a pH 7, y que se caracteriza por producir contracción y parálisis en la extremidad inoculada de ratones albinos. En este trabajo se ha determinado que la inoculacion de HI3 (26 µg) en el músculo gastrocenemius produce la liberación, en el plasma, de creatinina kanasa (CK) y lactado deshidrogenasa (LDH). La actividad de CK se incrementa desde 210 UI/L hasta 8015 UI/L luego de 60 minutos, mientras que la actividad de LDH aumentada desde 174 UI/L hasta 1697 UI/L luego de 90 minutos. Por PAGE-SDS, se ha demostrado que la incubación de HI3 (26 µg) con el músculo gastrocnemius aislado de ratones albinos, en medio fisiológico a pH, provoca también la liberación de otras proteínas musculares. Además, HI3 es capaz de incrementar más de 3,5 veces los niveles normales de calcio intramuscular, luego de 45 minutos de acción. Nuestros resultados sugieren que HI3 actúa específicamente a nivel muscular, afectando la permeabilidad del sarcolema y provocando la fuga de proteínas musculares. Además el incremento de los niveles de calcio podría generar hipercontracción y la destrucción de fibras musculares.
Asunto(s)
Calcio , Músculos , Toxinas Biológicas , Venenos de EscorpiónRESUMEN
Se han separado las proteínas del veneno de escorpión Hadruroides lunatus, por cromatografía de intercambio iónico en CM-Sephadex C-25 con buffer acetato de amonio 0,05M, pH 7, y se obtuvieron seis picos de proteína. Los ensayos de toxicidad de las fracciones colectadas han permitido identificar 3 toxinas que hemos denominado H11, H12, y H13, las cuales paralizan, respectivamente, insectos (Grillus sp.), crustáceos (Porcellio laevis) y la extremidad inoculada de ratones albinos. Las tres toxinas son de naturaleza básica, y carece de actividad proteolítica y fosfolipásica. Adicionalmente, H13 aumenta los niveles plasmáticos de creatinina kinasa, luego de ser inoculadas en el músculo gastrocnemius de ratones albinos. Por electroforesis en gel de poliacrilamida con dodecil sulfato de sodio (PAGES-SDS), se ha determinado que H13 muestra una sola banda proteica de 12,5 KDa, mientras que las otras toxinas poseen contaminantes proteicos.
