Direct in vitro regeneration of castor bean plants (Ricinus communis) using epicotyls / Regeneração direta in-vitro de plantas de mamona ( Ricinus communis ) usando epicótilos

A regeneration protocol for castor bean plant (Ricinus communis) was successfully developed using epicotyl sections obtained from in vitro seedlings. The maximum number of induced shoots (4.3 shoots/explant) and highest shoots frequency (75,56%) was obtained in WPM medium supplemented with TDZ (1 mg/L) and zeatin (0.5 mg/L), whereas the minimum number (0.8 shoots/explant) and lowest shoots frequency (37,78%) was obtained in medium containing TDZ (1 mg/L) and BAP (0.5 mg/L). The highest percentage of rooting (93.3%) was obtained in a medium containing IBA (1 mg/L). These plants were transplanted in a mesh house and achieved a high adaptability to acclimatization, reaching 77% survival. On the other hand, the maximum elongation (height) during this stage was 7.9 cm in plants supplemented with WPM nutrients, whereas it was only 4.38 cm in control plants

Foi desenvolvido com sucesso um protocolo de regeneração para a planta de Mamona (Ricinus communis) utilizando seções de epicótilos, obtidas a partir de mudas in vitro. O número máximo de brotações induzidas (4.3 brotos/explante), assim como a maior frequência de brotações (75,56%), foi obtido em meio WPM suplementado com TDZ (1 mg/L) e zeatina (0,5 mg/L). Enquanto que o número mínimo (0,8 brotos/explante), como a menor freqüência de rebentos (37,78%), foi obtido em meio contendo TDZ (1 mg/L) e BAP (0,5 mg/L). Adicionalmente, a maior percentagem de enraizamento (93,3%) foi obtida em um meio contendo IBA (1 mg/L). Depois da regeneração, as plantas foram transplantadas em casa de vegetação e conseguiram uma alta adaptabilidade e aclimatização, atingindo 77% de sobrevivência. Por outro lado, oalongamento máximo (altura) durante este estágio foi de 7,9 cm em plantas suplementadas com nutrientes de WPM, enquanto as plantas de controle presentaram apenas 4,38 cm

Ceratocystis cacaofunesta genome analysis reveals a large expansion of extracellular phosphatidylinositol-specific phospholipase-C genes (PI-PLC).

BACKGROUND: The Ceratocystis genus harbors a large number of phytopathogenic fungi that cause xylem parenchyma degradation and vascular destruction on a broad range of economically important plants. Ceratocystis cacaofunesta is a necrotrophic fungus responsible for lethal wilt disease in cacao. The aim of this work is to analyze the genome of C. cacaofunesta through a comparative approach with genomes of other Sordariomycetes in order to better understand the molecular basis of pathogenicity in the Ceratocystis genus. RESULTS: We present an analysis of the C. cacaofunesta genome focusing on secreted proteins that might constitute pathogenicity factors. Comparative genome analyses among five Ceratocystidaceae species and 23 other Sordariomycetes fungi showed a strong reduction in gene content of the Ceratocystis genus. However, some gene families displayed a remarkable expansion, in particular, the Phosphatidylinositol specific phospholipases-C (PI-PLC) family. Also, evolutionary rate calculations suggest that the evolution process of this family was guided by positive selection. Interestingly, among the 82 PI-PLCs genes identified in the C. cacaofunesta genome, 70 genes encoding extracellular PI-PLCs are grouped in eight small scaffolds surrounded by transposon fragments and scars that could be involved in the rapid evolution of the PI-PLC family. Experimental secretome using LC-MS/MS validated 24% (86 proteins) of the total predicted secretome (342 proteins), including four PI-PLCs and other important pathogenicity factors. CONCLUSION: Analysis of the Ceratocystis cacaofunesta genome provides evidence that PI-PLCs may play a role in pathogenicity. Subsequent functional studies will be aimed at evaluating this hypothesis. The observed genetic arsenals, together with the analysis of the PI-PLC family shown in this work, reveal significant differences in the Ceratocystis genome compared to the classical vascular fungi, Verticillium and Fusarium. Altogether, our analyses provide new insights into the evolution and the molecular basis of plant pathogenicity.

Reviewing Microbial Behaviors in Ecosystems Leading to a Natural Quorum Quenching Occurrence

ABSTRACT Quorum sensing is considered one of the most important discoveries in cell-to-cell communication. Although revealed in Bacteria, it has been identified as well as a mechanism present in the other two domains, Eukaryota and Archaea. This phenomenon consists mainly of an exchange and sensing of "words" produced by each cell: chemical signals known as autoinducers. The process takes places at high cell densities and confined environments, triggering the expression of specific genes that manifest in a determined phenotype. Quorum sensing has a fundamental importance in the organisms' fitness in natural ecosystems since it activates many of the traits needed by cells to survive under specific conditions, and thus a wide variety of chemical signals, which are detailed throughout the review, have evolved in response to the needs of an organism in the ecosystem it inhabits. As a counterpart, derived from the natural occurrence of quorum sensing, comes it's antagonistic process named quorum quenching. Acting in the exact opposite way, quorum quenching interferes or degrades the autoinducers confusing and stopping communication, hence affecting transcriptional regulation and expression of a specific phenotype. The main reasons for stopping this mechanism go from fading their own signals when perceiving scarce nutrients conditions, to degrading competitors' signals to take advantage in the ecosystem. Some of the most studied purposes and means known up to date to be used by cells for making quorum quenching in their ecosystems is what will be discussed along this review, offering information for future works on quorum quencher molecules bioprospection.

Mitochondrial genome characterization of Tecia solanivora (Lepidoptera: Gelechiidae) and its phylogenetic relationship with other lepidopteran insects.

The complete mitogenome of the potato tuber moth Tecia solanivora (Lepidoptera: Gelechiidae) was sequenced, annotated, characterized and compared with 140 species of the order Lepidoptera. The circular genome is 15,251 bp, containing 37 genes (13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and an A+T-rich region). The gene arrangement was identical to other lepidopteran mitogenomes but different from the ancestral arrangement found in most insects for the tRNA-Met gene (A+T-region, tRNA-I, tRNA-Q, tRNA-M). The mitogenome of T. solanivora is highly A+T-biased (78.2%) and exhibits negative AT- and GC-skews. All PCGs are initiated by canonical ATN start codons, except for Cytochrome Oxidase subunit 1 (COI), which is initiated by CGA. Most PCGs have a complete typical stop codon (TAA). Only NAD1 has a TAG stop codon and the COII and NAD5 genes have an incomplete stop codon consisting of just a T. The A+T-rich region is 332 bp long and contains common features found in lepidopteran mitogenomes, including the 'ATAGA' motif, a 17 bp poly (T) stretch and a (AT)8 element preceded by the 'ATTTA' motif. Other tandem repeats like (TAA)4 and (TAT)7 were found, as well as (T)6 and (A)10 mononucleotide repeat elements. Finally, this mitogenome has 20 intergenic spacer regions. The phylogenetic relationship of T. solanivora with 28 other lepidopteran families (12 superfamilies) showed that taxonomic classification by morphological features coincides with the inferred phylogeny. Thus, the Gelechiidae family represents a monophyletic group, suggesting that T. solanivora and Pectinophora gossypiella have a recent common ancestor.