Diversidad genética de papas de comunidades Andinas Venezolanas, mediante caracterización morfológica, molecular y polínica

In the communities of the state of Merida-Venezuela, the production of potatoes (Solanum tuberosum L.), one of the main agricultural products, where the wild species coexist, the so-called native and unnamed, the commercial varieties and the promising clones, which they are cultivated in many cases in an indistinct manner. The introduction of foreign varieties, both native, commercial and improved, have led to the gradual replacement of local varieties, accentuating the disappearance of our gene pool. Therefore, the characterization of local varieties is required, in order to determine their identification and diversity, as a fundamental principle for their preservation as an intangible heritage of our communities and their contribution to the country's food security. With this objective we have a concert in which we present the morphological, molecular and political characteristics of the Germoplasm samples located in the Experimental Field "Dr. Eduardo Ortega Cartaya", from different locations in the state of Mérida, as well as the samples located directly in the areas of the Merida region. A first characterization was obtained of 29 samples that correspond to molecular, morphological and political expressions that allow their identification and registration over time. From the statistical analyzes, it was possible to discriminate and group at a morphological, pollen and molecular level, which allowed to identify varieties with high potential to ensure the preservation of both wild, native and commercial local varietiesEn las comunidades del estado Mérida-Venezuela, la producción de papas (Solanum tuberosum L.) constituyen uno de los principales rubros agrícolas, donde conviven, las especies silvestres, las denominadas nativas y sin nombre, las variedades comerciales y los clones promisorios, que son cultivadas en muchos de los casos de manera indistinta. La introducción de variedades foráneas tanto nativas, comerciales y mejoradas, han llevado al remplazo paulatino de las variedades locales, acentuando la desaparición de nuestro acervo genético. Por lo que, se hace necesario la caracterización de las variedades locales, con la finalidad de determinar su identificación y su diversidad, como principio fundamental para su preservación como patrimonio intangible de nuestras comunidades y su contribución a la seguridad alimentaria del país. Con este objetivo se llevó a cabo la concertación de las características morfológicas, molecular y polínica de muestras de Germoplasma ubicadas en el Campo Experimental Mucuchies "Dr. Eduardo Ortega Cartaya", de diferentes localidades del estado Mérida, así como muestras localizadas directamente en zonas de la región merideña. Se obtuvo una primera caracterización de 29 muestras que comparten rasgos moleculares, morfológicos y polínicos que permiten su identificación y registro a través del tiempo. A partir de los análisis estadísticos se logró discriminar y agrupar a nivel morfológico, polínico y molecular, lo cual permitió identificar variedades con alto potencial para asegurar la preservación de variedades locales tanto silvestre, nativas y comerciales

Deletions and Mutations in the Acidic Lipid-binding Region of the Plasma Membrane Ca2+ Pump: A STUDY ON DIFFERENT SPLICING VARIANTS OF ISOFORM 2*

Acidic phospholipids increase the affinity of the plasma membrane Ca2+-ATPase pump for Ca2+. They interact with the C-terminal region of the pump and with a domain in the loop connecting transmembrane domains 2 and 3 (AL region) next to site A of alternative splicing. The contribution of the two phospholipid-binding sites and the possible interference of splicing inserts at site A with the regulation of the ATPase activity of isoform 2 of the pump by phospholipids have been analyzed. The activity of the full-length z/b variant (no insert at site A), the w/b (with insert at site A), and the w/a variant, containing both the 45-amino acid A-site insert and a C-site insert that truncates the pump in the calmodulin binding domain, has been analyzed in microsomal membranes of overexpressing CHO cells. The A-site insertion did not modify the phospholipid sensitivity of the pump, but the doubly inserted w/a variant became insensitive to acidic phospholipids, even if containing the intact AL phospholipid binding domain. Pump mutants in which 12 amino acids had been deleted, or single lysine mutations introduced, in the AL region were studied by monitoring agonist-induced Ca2+ transients in overexpressing CHO cells. The 12-residue deletion completely abolished the ATPase activity of the w/a variant but only reduced that of the z/b variant, which was also affected by the single lysine substitutions in the same domain. A structural interpretation of the interplay of the pump with phospholipids, and of the mechanism of their activation, is proposed on the basis of molecular modeling studies