Identification and deep analysis of teh molecular requirements for monocot malic enzyme genic expression

ANDREO CS; SAIGO M; DRINCOVICH, M. F.; GISMONDI, MAURO

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

NADP-dependent malic enzyme (NADP-ME) is widespread innature and involved in different metabolic pathways due to the relevantphysiological functions of its substrates (malate) and products(pyruvate and NADPH). In plants, this gene family harboursseveral members although the biological roles of each of themremain still unknown. Phylogenetic analysis of NADP-ME proteinsfrom monocot species revealed the existence of four taxonomic lineages,consisting of ortholog peptides with conserved amino acidicand structural features. Here, we explored the conservation ofmolecular requirements responsible for the specific spatio-temporalexpression patterns of each NADP-ME lineage, in order to deepenthe understanding of their biological functions. In particular, previoustranscriptional studies allowed us to classify a maize NADP-MEisoform as embryo-specific. An own design software was appliedto perform a deep analysis on the regulatory sequences of morethan ten orthologous genes of this clade and a novel cis-regulatorymodule (CRM) was identified. This conserved arrangement of motifsincluded two specific ABREs (ABA-Responsive Element) andother uncharacterized cis-elements. Moreover, the study of theirproximal genomic context revealed the putative bidirectionality ofthese promoters, sharing the found cis-elements and their potentialfunctionality with OVA4 (OVule Abortion 4), a gene with a reportedrole in embryo development. In silico transcriptional evidenceswere explored for these adjacent genes and also for potential transregulators of their promoters in monocot seed development. Thesefindings, along with distinct conserved features found for the otherlineages, provide new insights and trigger new hypothesis in order tounravel the specific roles of each NADP-ME isoform, to validate theirpossible redundancy, and to understand the extents of the functionaldiversity of this family of metabolic enzymes.