Genome-Wide Survey of Invertase Encoding Genes and Functional Characterization of an Extracellular Fungal Pathogen-Responsive Invertase in Glycine max

Abstract

Invertases are essential enzymes that irreversibly catalyze the cleavage of sucrose into glucose and fructose. Cell wall invertase (CWI) and vacuolar invertase (VI) are glycosylated proteins and exert fundamental roles in plant growth as well as in response to environmental cues. As yet, comprehensive insight into invertase encoding genes are lacking in Glycine max. In the present study, the systematic survey of gene structures, coding regions, regulatory elements, conserved motifs, and phylogenies resulted in the identification of thirty–two putative invertase genes in soybean genome. Concomitantly, impacts on gene expression, enzyme activities, proteins, and soluble sugar accumulation were explored in specific tissues upon stress perturbation. In combination with the observation of subcellular compartmentation of the fluorescent fusion protein that indeed exported to apoplast, heterologous expression, and purification in using Pichia pastoris system revealed that GmCWI4 was a typical extracellular invertase. We postulated that GmCWI4 may play regulatory roles and be involved in pathogenic fungi defense. The experimental evaluation of physiological significance via phenotypic analysis of mutants under stress exposure has been initiated. Moreover, our paper provides theoretical basis for elucidating molecular mechanisms of invertase in association with inhibitors underlying the stress regime, and will contribute to the improvement of plant performance to a diverse range of stressors.