Isolation of total RNA from ripe and unripe soursop (Annona muricata L.) fruit

Soursop fruit tissue is known by its acidic pH and high levels of polysaccharides, polyphenolics and secondary metabolites. These conditions are recognized to interfere unfavorably with conventional methodologies for RNA isolation. We describe here a rapid and simple method for the isolation of total RNA from soursop fruit. RNA was extracted in less than 4 h through a combination of SDS/potassium acetate precipitation and selective binding on a silica-gel-based membrane (Qiagen) through microspin speed technology. In comparison to other methods applied for RNA extraction from soursop fruit, our protocol improved substantially RNA quality as well as RNA yield. The isolated RNA served as a robust template for RT-PCR analysis. Comparable RNA quality and yield per dry weight were obtained from unripe and ripe fruits. This makes the method appropriate to being used in studies on differential gene expression in post-harvest behavior

Vacuolar proton pumps regulation during development of Vigna unguiculata seedlings under salt stress

Global climatic changes as high temperatures and low precipitation contribute to increase cultivated areas affected by high salt soil content. Soil salinity is well known to reduce the ability of plants to take up water and this quickly causes reduction in their growth rate. V-ATPase (EC 3.6.3.14) and V-PPase (EC 3.6.1.1) hydrolytic and proton transport activities, and gene expression were evaluated in hypocotyls of 3-, 5-, 7-day-old Vigna unguiculata (L.) Walp cv. Vita 3 germinated in 100 mM NaCl in order to highlight their differential regulation and activity modulation under salt stress. Semi-quantitative RT-PCR revealed that both genes were up-regulated by salt stress in all salt exposition times studied. Up-regulation was correlated with the increase in protein content at 5 and 7-day-old seedlings. Co-expression between A and E V-ATPase subunits was also observed. The hydrolytic and proton transport activities showed that these enzymes presented a differential modulation of their activities in the presence of 100 mM NaCl. These results suggest that V-ATPase and V-PPase activities are modulated by salt stress and a multi-step regulation is exerted in order to re-establish homeostasisFil: Menezes Sobreira, Alana Cecília. Universidade Estadual Do Ceara; Brasil. Universidade Federal Do Ceara; BrasilFil: Maia, Yuri. Universidade Federal Do Ceara; BrasilFil: Rebouças, Deborah Moura. Universidade Federal Do Ceara; BrasilFil: Costa, José Hélio. Universidade Federal Do Ceara; BrasilFil: Oliveira Otoch, Maria de Lourdes. Universidade Estadual Do Ceara; BrasilFil: Nogueira de Oliveira, Luciana Maia. Universidade Federal Rural Pernambuco; BrasilFil: Orellano, Elena Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Fernandes de Melo, Dirce. Universidade Federal do Ceará; Brasi