Expression analysis of Mildew Resistance Locus O of cacao in resistant and susceptible plants infected by Moniliophthora perniciosa : S01P03

A Mildew Resistance Locus O (MLO) cDNA was identified from a library of Theobroma cacao L. meristems (Catongo varieties) infected by Moniliophthora perniciosa, the fungus responsible for the witches' broom disease. In other plants, the MLO gene is characterized as a defense and programmed cell death (PCD) modulator, and for this reason may be a good candidate for functional studies aiming the increase of plant resistance. An in silico analysis of the cacao MLO (TcMLO) using the BLAST, Pfam, InterProScan and ORF-Finder programs, as well as a search on CocoaGenDB databank were performed. TcMLO belongs to a multigene family of proteins containing 19 sequences present in the cacao genome: 12, 5 and 2 of them showed one, two and three MLO domains, respectively. The complete TcMLO sequence (including UTRs and ORF) is 5712 bp in length with 13 exons and 12 introns, and is located on the chromosome 5. The TcMLO ORF is 1629 bp in length and encodes a protein with 542 amino acids containing 2 MLO domains. The expression of TcMLO was analyzed by quantitative PCR (qPCR) in resistant (TSH1188) and susceptible (Catongo) cacao varieties infected or not by Moniliophthora perniciosa. Plantlets of cacao were inoculated by the droplet method with a basidiospore suspension of M. perniciosa. After inoculation, the plantlets were kept for 24h at 25±2ºC and 100% humidity. Apical meristems were harvested in triplicates at 24, 48 and 72 hours after inoculation (hai), and 8, 15, 30, 45, 60 and 90 days after inoculation (dai). Non-inoculated plants (controls) were kept and harvested in the same conditions. The qPCR of Tc MLO was obtained using the standard settings of the ABI PRISM 7500 and using the System of Sequence Detection software. The TcMLO expression was analyzed with the comparative Ct method (2-??Ct) using malate dehydrogenase and actin as endogenous reference genes, and non-inoculated plants (control) as calibrator. The results showed that TcMLO was more expressed in Catongo than in TSH1188 at the early and final stages of disease. In TSH1188, the highest expression of MLO was observed at 15 dai. The expression of TcMLO at the final stage of the disease in the susceptible infected plants may be related to the PCD events occurring in this variety as a signal for the finalization of the fungus life cycle. Funding Agency: FAPESB, CNPq, CAPES, EMBRAPA, FINEP/Renorbio and CIRAD. (Texte intégral

MLO and SBP genes from Theobroma cacao are differencially expressed between resistent and suscetible cacao plants infected with Moniliophthora perniciosa

Among sequences previously identified as potentially envolved in the resistance versus susceptibility of Theobroma cacao to the fungus Moniliophthora perniciosa, the MLO (Mildew resistance lócus O) and the SBP (selenium binding protein) genes were found. The MLO gene is characterized as a plant defense and programmed cell death modulator, and the SBP gene was successfully used to increase the rice resistance to Magnaporthe grisea by plant transformation, among other applications. The objective of this work was to evaluate the expression of the MLO and SBP genes from T. cacao in cacao plants infected by M. perniciosa. Varieties of cacao resistant (TSH1188) and suceptible (Catongo) to M. perniciosa were inoculated with a suspension of fungus basidiospores (2.105. ml-1). After inoculation, the plants were kept for 24h at 25±2ºC under 100% of humidity. Apical meristems were harvested in triplicates at 24, 48 and 72 hours after inoculation (hai) and 30, 60 and 90 days after inoculation (dai). Non-inoculated plants (controls) were kept and harvested in the same conditions. Total RNA was extracted using the RNAqueous Kit® (Ambion). First strand cDNA was obtained using the Revertaid Fisrt Strand cDNA Synthesis Kit (Thermo Scientific, Fermentas). Quantitative PCR (qPCR) of MLO and SBP was obtained using the standard settings of the ABI PRISM 7500 and System of Sequence Detection (SDS) software, v.1.6.3 (Applied Biosystems). The expression levels of MLO and SBP was analyzed on triplicates with the comparative Ct method (2-??Ct) using malate dehydrogenase and actin as endogenous reference genes, and non-inoculated plants (control) were used as a calibrator. At the early stages of infection and in the final stage of the disease, the MLO gene was more expressed in Catongo than in TSH1188. In TSH1188, the highest expression of MLO was observed at 30 dai. The SBP gene was highly expressed in TSH1188 at the late stages after infection while in Catongo, the expression was high at the early stages and then constant until the end of the disease. The involvement in the cacao-M. perniciosa interaction of both MLO and SBP genes is discussed. Financial Support: CNPq, BNB, FINEP/Renorbio, Cirad. (Résumé d'auteur

On a parabolic strongly nonlinear problem on manifolds

In this work we will prove the existence uniqueness and asymptotic behavior of weak solutions for the system (*) involving the pseudo Laplacian operator and the condition $\displaystyle\frac{\partial u}{\partial t} + \sum_{i=1}^n \big|\frac{\partial u}{\partial x_i}\big|^{p-2}\frac{\partial u}{\partial x_i}\nu_i + |u|^{\rho}u=f$ on $\Sigma_1$, where $\Sigma_1$ is part of the lateral boundary of the cylinder $Q=\Omega \times (0,T)$ and $f$ is a given function defined on $\Sigma_1$

In silico characterization and expression analysis of a Selenium-Binding Protein gene from cacao : S01P01

Witches' broom disease, caused by the fungus Moniliophthora perniciosa, is one of the main diseases of cacao (Theobroma cacao L.) and is responsible to severe economic losses in the production areas. Recently, expressed sequence tags (ESTs) from cacao-M. perniciosa interaction were obtained and differentially defense-related genes expressed during the cacao-M. perniciosa interaction were identified. Among them, a Selenium-Binding Protein (TcSBP) was found. In other organisms, SBP genes are related to the increase of plant defenses against abiotic and biotic stresses; in rice the SBP gene was successfully used to increase the plant resistance to Magnaporthe grisea by plant transformation. Here, in silico characterization and expression analysis of TcSBP were developed. Search on the Cacao Genome Database revealed the presence of only one SBP sequence of 4774 pb in length located on the chromosome 4. The TcSBP ORF is 1431 bp in length and encodes a protein of 476 amino acids which does not contain any signal peptide. Prediction of possible post-translational events allowed the identification of several glycosylation, phosphorylation and acetylation sites. The comparison of TcSBP sequence with SBP from other organisms using the BLASTP tool revealed identity from 62% to 91% and allowed the identification of specific conserved regions. The expression analysis of TcSBP in meristems of cacao plantlets varieties Catongo (susceptible) and TSH1188 (resistant to M. perniciosa), inoculated or not with M. perniciosa, was obtained by RT-qPCR using 3 biological and 3 experimental replicates. qPCR analysis of TcSBP gene was conducted using the standard settings of the ABI PRISM 7500 and the System of Sequence Detection software. The TcSBP relative expression was analyzed with the comparative Ct method (2-??Ct) using malate dehydrogenase and actin as endogenous reference genes, and noninoculated plants (control) as calibrator. The relative expression of TcSBP was significantly increased 8 and 15 days after inoculation in the resistant variety TSH1188 compared to susceptible Catongo. These data suggest the possible role of TcSBP in cacao resistance to M. perniciosa. This study is the first step to better understand the role of TcSBP in cacao resistance as well as for the development of control strategies of the witches' broom disease (e.g. using plant transformation). Work supported by FAPESB, CAPES, EMBRAPA, CNPq, FINEP/Renorbio and CIRAD. (Texte intégral

Failure of sexing by developmental arrest of bovine embryos in vitro produced with H-Y antisera

Embriões bovinos produzidos in vitro, em estádio de mórula, foram cultivados em meio contendo anticorpos anti H-Y de alto título proveniente de ratos por 24h e, após este tempo, classificados em dois grupos: 1) embriões inibidos em estádio de mórula (classificados como machos) e 2) embriões que se desenvolveram e formaram a blastocele (classificados como fêmeas). O sexo de 311 embriões, distribuídos em três grupos de concentração dos anticorpos, 3%, 5% ou 7%, foi identificado pela reação em cadeia da polimerase. Não houve desvio da proporção entre machos e fêmeas (P>0,05) nos grupos em que se utilizaram os anticorpos anti H-Y, quando comparadas ao grupo-controle, sem adição de anticorpos anti H-Y. Diferentemente dos resultados obtidos utilizando-se embriões bovinos produzidos in vivo, a sexagem com anticorpos anti H-Y de alto título em embriões produzidos in vitro não propiciou sucesso.In vitro produced bovine embryos at morula stage were cultured in medium containing high titer of rat H-Y antisera for 24h. The embryos were classified in two groups: 1) embryos arrested at morula stage (classified as males); and 2) embryos that developed and formed a blastocoele (classified as female). The sex of 311 embryos, divided in three groups of concentration of H-Y antisera, 3%, 5% or 7%, was identified by polimerase chain reaction. The results showed no difference (P>0.05) on sexual deviation in groups in which the H-Y antisera was added, in relation to control group, in which no H-Y antisera was added. In contrast with results obtained with in vivo produced bovine embryos, the sexing of in vitro produced bovine embryos with high H-Y antisera titer did not succed.CNP

Decomposition and nutrient release of leguminous plants in coffee agroforestry systems.

Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and(lignin+polyphenol)/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD), the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA), there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1). Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants

A Biased Review of Sociophysics

Various aspects of recent sociophysics research are shortly reviewed: Schelling model as an example for lack of interdisciplinary cooperation, opinion dynamics, combat, and citation statistics as an example for strong interdisciplinarity.Comment: 16 pages for J. Stat. Phys. including 2 figures and numerous reference