Alkaline/Netural Invertase gene family in Populus tremula

BRIONES MARÍA V; SHARRY SANDRA E.; BATTAGLIA MARINA; KOLMAN MARÍA A.; SALERNO GRACIELA L.

Buenos Aires

Simposio; VII International Poplar Symposium; 2018

Internacional Poplar Commission- IUFRO

The poplar has become a model organism for tree genomics and biotechnology studies because of its especial attributes (rapid growth, easy vegetative propagation, and relatively small genome) and its economic importance worldwide. In Argentina, Populus tremula in addition to P. deltoides, P. nigra, and P. trichocarpa have been the basis for breeding programs. Plantations tolerant to environmental stress need the development of novel materials based on new molecular tools for selection. Alkaline/neutral invertases (A/N-Invs), enzymes that irreversibly hydrolyze sucrose into glucose and fructose, have been shown to be involved in stress responses in several plant species (e.g., Arabidopsis thaliana, Oryza sativa, Triticum aestivum). A recent study in Poncirus trifoliata demonstrated that the expression of an A/N-Inv isoform is induced by low temperature, salt treatment, and drought. Also, the expression of some A/N-Invs increased after cold and salt treatments in P. tomentosa. The aim of our study is to identify stress markers in Populus from studies on P. tremula, whose genome was recently sequenced. We first identified and characterized 12 putative genes in the P. tremula genome coding for A/N-Inv family members (Ptra-NINVs), using as query P. trichocarpa and A. thaliana sequences. A comprehensive analysis of Ptra-NINVs genes was carried out, including gene structure, chromosomal location, comparative expression profiles, as well as protein phylogeny, and subcellular localization of the different isoforms using predictors (Predotar, Target P, Wolf Psort) and experimental approaches. The phylogenetic analysis indicated that the Ptra-NINV family members clustered into two clades. Six of the 12 putative Ptra-NINV deduced proteins were predicted as cytosolic isoforms and grouped in the ß-clade together with characterized cytosolic proteins from other plant species. The 6 remaining Ptra-NINV sequences that grouped in the α-clade were characterized as putative mitochondrial (3) and chloroplastic (3) isoforms. We performed preliminary experiments to identify isoforms involved in cold and salt stress response. These results will allow us to identify abiotic stress markers as tools in Populus breeding programs.