Abstract

MONROY-GONZALEZ, Zurisadaí  and  MARTINEZ-HERNANDEZ, Aída. IDENTIFICATION OF cDNAs FROM Agave tequilana Weber Var. azul SIMILAR TO FUROSTANOL GLYCOSIDE 26-O-β-GLUCOSIDASES. Rev. fitotec. mex [online]. 2019, vol.42, n.4, pp.439-447.  Epub Oct 16, 2020. ISSN 0187-7380.

Furostanol glycoside 26-O-β-glucosidase (F26G) participates in the last step of steroidal saponin biosynthesis, cleaving the glucose bound to the C26 of the hydroxylin furostanol glucoside to allow the formation of spirostane. Despite the existence of numerous studies showing the structural diversity and biological activity of plant saponins, as well as their recognized biotechnological and pharmacological potential, few enzymes involved in the biosynthetic pathway of steroidal saponins have been studied and only one native F26G enzyme has been isolated and functionally characterized. In this study, by searching a database of Agave tequilana Weber var. azul (Agave DB), 46 ESTs (Expressed Sequence Tags) of complementary DNA (cDNAs) similar to the known F26G were identified through BLASTX, most come from cDNA from floral tissues (anthers and ovaries) or roots; both organs are saponins producers. Among them, six ESTs were identified whose alignment indicates that they represent three cDNAs different from each other. These ESTs were submitted to the dbEST database of NCBI (National Center for Biotechnology Information), being this the first record of native cDNA sequences putatively encoding F26G-like in Agave. The size of the cloned cDNAs and their alignment to the 5’ end of the known F26G suggest they are full-length cDNAs. Specific differential primers were designed for each type of cDNA and their expression in vegetative tissues of A. tequilana was analyzed by RT-PCR. Quantitative PCR protocols (qPCR) were established for future studies on gene expression regulation. The information reported here will serve as a basis for studying the function, regulation and enzymatic activity of F26G-like cloned from Agave.

Keywords : Agave tequilana; cDNA; EST; furostanol glycoside 26-O-β-glucosidase; saponins.