Kinetics and functional diversity among the five members of the NADP-malic enzyme family from Zea mays, a C4 species

Abstract

NADP-malic enzyme (NADP-ME) is involved in different metabolic pathways in several organisms due to the relevant physiological functions of the substrates and products of its reaction. In plants, it is one of the most important proteins that were recruited to fulfil key roles in C4 photosynthesis. Recent advances in genomics allowed the characterization of the complete set of NADP-ME genes from some C3 species, as Arabidopsis thaliana and Oryza sativa; however, the characterization of the complete NADP-ME family from a C4 species has not been performed yet. In this study, while taking advantage of the complete Zea mays genome sequence recently released, the characterization of the whole NADP-ME family is presented. The maize NADP-ME family is composed of five genes, two encoding plastidic NADP-MEs (ZmC4- and ZmnonC4-NADP-ME), and three cytosolic enzymes (Zmcyt1-, Zmcyt2-, and Zmcyt3-NADP-ME). The results presented clearly show that each maize NADP-ME displays particular organ distribution, response to stress stimuli, and differential biochemical properties. Phylogenetic footprinting studies performed with the NADP-MEs from several grasses, indicate that four members of the maize NADP-ME family share conserved transcription factor binding motifs with their orthologs, indicating conserved physiological functions for these genes in monocots. Based on the results obtained in this study, and considering the biochemical plasticity shown by the NADP-ME, it is discussed the relevance of the presence of a multigene family, in which each member encodes an isoform with particular biochemical properties, in the evolution of the C4 NADP-ME, improved to fulfil the requirements for an efficient C4 mechanism.

Inhibition of NADP‐malic enzyme activity by H2S and NO in sweet pepper (Capsicum annuum L.) fruits

“…In plants, both photosynthetic and non‐photosynthetic NADP‐ME isozymes have been found in both plastids and the cytosol (Chen et al ). Cytosolic NADP‐MEs appear to be involved in processes such as pyruvate metabolism, carbon fixation, lignin biosynthesis, plant defense responses, cytosolic pH regulation and stomatal closure (Edwards and Andreo , Drincovich & Andreo 1994, Schaaf et al , Casati et al , Drincovich et al 2001, Alvarez et al , , Arias et al , Kandoi et al 2018). Recently, NADP‐ME has been shown to play an important role in A. thaliana mutants lacking cytosolic NADP‐ME1, whose seeds have reduced viability associated with increased protein carbonylation content which is a marker of oxidative stress (Yazdanpanah et al ).…”

Parallel Recruitment of Multiple Genes into C4 Photosynthesis

“…Different forms of some C 4 -related enzymes have different expression patterns, in terms of diurnal regulation and the tissues, cells, and subcellular compartments in which the enzyme is expressed (Maurino et al 1997; Finnegan et al 1999; Tausta et al 2002; Alvarez et al 2013). A function in C 4 photosynthesis requires light-induced high expression levels in specific cell types of the leaf (Sheen 1999).…”

“…In addition to expression patterns, the enzymes encoded by different members of the same gene family also differ in their catalytic properties (Ting and Osmond 1973; Tausta et al 2002; Svensson et al 2003; Alvarez et al 2013). In several of the C 4 -related genes, the evolution of C 4 -specific forms involved adaptive mutations of the coding sequence, which suggests catalytic modifications during the C 3 to C 4 transition (PEPC [Christin et al 2007; Wang et al 2009]; PCK [Christin, Petitpierre et al 2009]; NADP-ME [Christin, Samaritani et al 2009, Wang et al 2009]; CA, PPDK, PPDK-RP [Wang et al 2009]).…”

Synergistic binding of bHLH transcription factors to the promoter of the maize NADP-ME gene used in C4 photosynthesis is based on an ancient code found in the ancestral C3 state

“…In vitro, the 177 bicolor possess two plastidic NADP-ME isoforms: one that is used in C 4 210 photosynthesis (C 4 -NADP-ME, GRMZM2G085019 and Sobic.003g036200) and a 211 second one not involved in the C 4 cycle (nonC 4 -NADP-ME, GRMZM2G122479 and 212 Sobic.009g108700). In contrast, S. italica possesses only one plastidic NADP-ME 213 isoform that is used in the C 4 cycle (C 4 -NADP-ME, Si000645) (Alvarez et al 2013). Since ZmbHLH128 and ZmbHLH129 showed weak binding to single cis-251 elements, we tested their binding by mutating these cis-elements in probes with the 252 pairs (supplementary fig.…”