Artículos y presentaciones en Congresos

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Examinando Artículos y presentaciones en Congresos por Autor "Andreu, A.B."

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  • Documento de conferencia
    Acceso Abierto
    Analysing the expression of genes associated with induced resistance in potato plants treated with phosphites
    (2009) Machinandiarena, M.F.; Feldman, M.; Daleo, Gustavo Raúl; Andreu, A.B.
    Phosphites (Phi) have the ability to protect plants against different pathogens, both through a direct effect in oomycete metabolism and by an indirect effect stimulating the plant´s natural defence responses. We have previously shown that KPhi foliar application to potato plants resulted in different protection levels against Phytophthora infestans depending on dose and plant age at application time. In order to identify genes that are involved in induced resistant in plants treated with KPhi, we analyzed by RT PCR, the time course of transcript levels of two genes which encode predicted transcription factors involved in pathogen perception and defence gene expression. Preliminary results showed that WRKY and NPR1 were differentially induced in plants both treated with Phi and infected with Phytophthora infestans, showing an earlier and highest induction than infected plants non treated with Phi. These results may allow us to hypothetize that Phi treatment might trigger a fast mechanism to protect potato plants to pathogen infections.
  • Documento de conferencia
    Acceso Abierto
    Differentially expressed genes in potato sprouts after potassium phosphite application
    (2009) Feldman, M.; Machinandiarena, M.F.; Amarilla, L.D.; Guzzo, M.C.; Di Rienzo, J.; Daleo, Gustavo Raúl; Andreu, A.B.
    We are studying the role of phosphites in disease control management, yield and potato tuber quality. In brief, our previous results showed a number of promising properties associated with these compounds. When we applied potassium phosphites (KPhi) at 3 litre $latex ha^{-1} $ to seed tubers immediately after cutting, this promoted early emergence, an increased in stem number and diameter, early tuber initiation and an increased in the number of tubers per plant. In addition to these physiological effects, phosphite treatment also resulted in greater resistance in seed tubers to Phytophthora infestans, Fusarium solani and Rhizoctonia solani. In order to understand the mechanisms which regulate these responses, we analyzed the changes in gene expression in tubers seeds at early stage of sprouting after KPhi treatment. Preliminary results of microarray analysis from potato sprouts treated or not with KPhi, showed that 26 genes were upregulated in the treated ones. These genes were classified into 5 groups: plant defense, metabolism, abiotic stress, transcription factors and unknown genes. We performed semiquantitative RT-PCR assays of some of these genes to validate the results. Interestingly one of these genes was CULLIN 1, involved in jasmonic acid mediated signaling pathway. This result may support the hypothesis that phophites could be involved in triggering IR (induced resistant).
  • Artículo
    Acceso Abierto
    Molecular modifications in tuber periderm and cortex associated to pathogen resistance induced by phosphite treatment
    (2012) Olivieri, F.P.; Feldman, M.; Machinandiarena, M.F.; Lobato, M.C.; Caldiz, D.; Daleo, Gustavo Raúl; Andreu, A.B.
    Phosphite (Phi) compounds are salts derived from phosphorous acid. These compounds have the ability to protect plants against different pathogens. The aim of the present research was to assess the effect of Phi compounds on components of potato tuber periderm and cortex and to assess their effects on pathogen resistance in the postharvest stage. In a series of field experiments, potassium phosphite (KPhi) was applied to seed potato tubers and foliage. After harvest, several variables were analyzed in tubers obtained from these plants. An increase in pectin content was observed in both periderm and cortex tissue in tubers originating from KPhi-treated plants. After wounding and infection with Fusarium solani, a higher amount of pectin accumulation in cortical tissues was observed in tubers following treatment with KPhi. The content and/or activity of polygalacturonase and proteinase inhibitor also increased in tubers from KPhi-treated plants. A new isoform of chitinase was detected in the tuber periderm of treated plants. These results suggest that KPhi applied to seed tuber and foliage induces defense responses in tuber periderm and cortex and that these reactions are associated with structural and biochemical changes in these tissues.
  • Artículo
    Acceso Abierto
    PLPKI: A novel serine protease inhibitor as a potential biochemical marker involved in horizontal resistance to Phytophthora infestans
    (2014) Feldman, M.; Andreu, A.B.; Korgan, S.; Lobato, M.C.; Huarte, M.; Lee Walling, Linda; Daleo, Gustavo Raúl
    Potato leaves infected with Phytophthorainfestans produced a serine protease inhibitor (PLPKI) with specificity for microbial proteases. Sequencing of the first twenty residues at the NH2-terminus of the mature PLPKI polypeptide demonstrated that PLPKI is a novel member of the potato protease inhibitor I family. PLPKI inhibited the activity of extracellular proteases produced by two pathogens of potato, P.infestans and Rhizoctoniasolani, but was inactive against proteases secreted into the culture media by the binucleate Rhizoctonia N2, a non-pathogenic fungus for potato. Western blot analysis showed a positive correlation between the levels of PLPKI and the degree of horizontal resistance, showing its highest accumulation in clone OKA 5632.11, which has been described as highly resistant. This correlation, together with the ability of PLPKI to completely abolish the secreted serine protease activity of P.infestans, suggests that PLPKI may have an active role in protecting potato plants from this pathogenic oomycete and that it could be used as a suitable biochemical marker to help breeders in the selection of cultivars with high degree of horizontal resistance.
  • Artículo
    Acceso Abierto
    Potassium phosphite primes defense responses in potato against
    (2012) Machinandiarena, M.F.; Lobato, M.C.; Feldman, M.; Daleo, Gustavo Raúl; Andreu, A.B.
    Although phosphite is widely used to protect plants from pathogenic oomycetes on a wide range of horticultural crops, the molecular mechanisms behind phosphite induced resistance are poorly understood. The aim of this work was to assess the effects of potassium phosphite (KPhi) on potato plant defense responses to infection with Phytophtora infestans (Pi). Pathogen development was severely restricted and there was also an important decrease in lesion size in infected KPhi-treated leaves. We demonstrated that KPhi primed hydrogen peroxide and superoxide anion production in potato leaves at 12 h post-inoculation with Pi. Moreover, the KPhi-treated leaves showed an increased and earlier callose deposition as compared with water-treated plants, beginning 48 h after inoculation. In contrast, callose deposition was not detected in water-treated leaves until 72 h after inoculation. In addition, we carried out RNA gel blot analysis of genes implicated in the responses mediated by salicylic (SA) and jasmonic acid (JA). To this end, we examined the temporal expression pattern of StNPR1 and StWRKY1, two transcription factors related to SA pathway, and StPR1 and StIPII, marker genes related to SA and JA pathways, respectively. The expression of StNPR1 and StWRKY1 was enhanced in response to KPhi treatment. In contrast, StIPII was down regulated in both KPhi- and water-treated leaves, until 48 h after infection with Pi, suggesting that the regulation of this gene could be independent of the KPhi treatment. Our results indicate that KPhi primes the plant for an earlier and more intense response to infection and that SA would mediate this response.