Browsing by Author "Fernandes, J.C."
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- Immunolocalization of cell wall polymers in grapevine (Vitis vinifera) internodes under nitrogen, phosphorus or sulfur deficiencyPublication . Fernandes, J.C.; Goulão, L.F.; Amâncio, S.Abstract The impact on cell wall (CW) of the deficiency in nitrogen (–N), phosphorus (–P) or sulphur (–S), known to impair essential metabolic pathways, was investigated in the economically important fruit species Vitis vinifera L. Using cuttings as an experimental model a reduction in total internode number and altered xylem shape was observed. Under –N an increased internode length was also seen. CW composition, visualised after staining with calcofluor white, Toluidine blue and ruthenium red, showed decreased cellulose in all stresses and increased pectin content in recently formed internodes under –N compared to the control. Using CW-epitope specific monoclonal antibodies (mAbs), lower amounts of extensins incorporated in the wall were also observed under –N and –P conditions. Conversely, increased pectins with a low degree of methyl-esterification and richer in long linear 1,5-arabinan rhamnogalacturonan-I (RG-I) side chains were observed under –N and –P in mature internodes which, in the former condition, were able to form dimeric association through calcium ions. –N was the only condition in which 1,5-arabinan branched RG- content was not altered, as –P and –S older internodes showed, respectively, lower and higher amounts of this polymer. Higher xyloglucan content in older internodes was also observed under –N. The results suggest that impairments of specific CW components led to changes in the deposition of other polymers to promote stiffening of the CW. The unchanged extensin amount observed under –S may contribute to attenuating the effects on the CW integrity caused by this stress. Our work showed that, in organized V. vinifera tissues, modifications in a given CW component can be compensated by synthesis of different polymers and/or alternative linking between polymers. The results also pinpoint different strategies at the CW level to overcome mineral stress depending on how essential they are to cell growth and plant development.
- Regulation of cell wall remodeling in grapevine (Vitis vinifera L.) callus under individual mineral stress deficiencyPublication . Fernandes, J.C.; Goulão, L.F.; Amâncio, S.
- Relating water deficiency to berry texture, skin cell wall composition and expression of remodeling genes in two Vitis vinifera varietiesPublication . Fernandes, J.C.; Cobb, F.; Tracana, S.; Costa, G.J.; Valente, I.; Goulão, L.F.; Amâncio, S.The cell wall (CW) is a dynamic structure that responds to stress. Water shortage (WS) impacts grapevine berry composition and its sensorial quality. In the present work, berry texture, skin CW composition, and expression of remodeling genes were investigated in two V. vinifera varieties, Touriga Nacional (TN) and Trincadeira (TR), under two water regimes, Full Irrigation (FI) and No Irrigation (NI). The global results allowed an evident separation between both varieties and the water treatments. WS resulted in increased anthocyanin contents in both varieties, reduced amounts in cellulose and lignin at maturation, but an increase in arabinose-containing polysaccharides more tightly bound to the CW in TR. In response to WS, the majority of the CW related genes were down-regulated in a variety dependent pattern. The results support the assumption that WS affects grape berries by stiffening the CW through alteration in pectin structure, supporting its involvement in responses to environmental conditions.
- Tackling the cell wall of the grape berryPublication . Goulão, L.F.; Fernandes, J.C.; Lopes, P.; Amâncio, SaraAbstract: The cell wall (CW) is the dynamic border of plant cells. In grape berries, the CW decisively accounts for the difference between the pulp and skin cells, with direct consequences on the grape characteristics, wine quality and wine-making methods. The softening of mature berries results from the depolymerisation and solubilisation of CW polymers. Modifications of grape pulp and skin CW provide the flexibility for cell expansion during fruit growth and to modulate the final texture. Wine making and berry processing methods are directly related with the absence, in white wines, or the presence, in red wines, of skin CW in the fermenting must. Anthocyanin extraction depends directly on skin yielding of the pigment upon CW degradation. During fruit growth and ripening, the cooperative action between different enzyme families is capital in CW metabolism. The sequencing and public availability of the Vitis genome allowed us to focus on individual pathways, to profile the expression pattern of isoforms associated with each tissue, developmental phase or stress response, anticipating the effects on berry (and wine) production and quality. Retrieving the sequences of genomic coding regions and the predicted enzymes that act on the Vitis, CW allows us for the first time to tackle the grape berry Cell Wallome
- Tackling the cell wall of the grape berryPublication . Goulão, L.F.; Fernandes, J.C.; Lopes, P.; Amâncio, SaraThe cell wall (CW) is the dynamic border of plant cells. In grape berries, the CW decisively accounts for the difference between the pulp and skin cells, with direct consequences on the grape characteristics, wine quality and wine-making methods. The softening of mature berries results from the depolymerisation and solubilisation of CW polymers. Modifications of grape pulp and skin CW provide the flexibility for cell expansion during fruit growth and to modulate the final texture. Wine making and berry processing methods are directly related with the absence, in white wines, or the presence, in red wines, of skin CW in the fermenting must. Anthocyanin extraction depends directly on skin yielding of the pigment upon CW degradation. During fruit growth and ripening, the cooperative action between different enzyme families is capital in CW metabolism. The sequencing and public availability of the Vitis genome allowed us to focus on individual pathways, to profile the expression pattern of isoforms associated with each tissue, developmental phase or stress response, anticipating the effects on berry (and wine) production and quality. Retrieving the sequences of genomic coding regions and the predicted enzymes that act on the Vitis, CW allows us for the first time to tackle the grape berry Cell Wallome