Análise genômica comparativa da família de genes Glicolato oxidase (gox) em plantas e perfil de expressão de vugox1 durante estresse biótico em Vigna unguiculata [L.] Walp.

Abstract

Glycolate Oxidase (GOX) is a key enzyme in photorespiration, a complex metabolic pathway in plants that affects photosynthesis efficiency and presents as one of its most prominent products hydrogen peroxide (H2O2). Photosynthetic pathways and H2O2 production can drastically differ between C3 and C4 plants, where several distinctions rely on the photorespiration machinery. Such contrasts impact in crucial physiological processes in plants, such as development and stress responses. However, few studies bring light to evolutionary and structural aspects of the photorespiration components, as well as comparative analyses of gene families related to photorespiration in C3 and C4 plants are lacking. In the present study, we present the first genome-wide comparative analysis of GOX gene family in plants, comparing relevant evolutionary and structural aspects of distinct GOX orthologs in plant families. The evolutionary relationships, gene structure, conserved motifs, promoter cis-elements prediction, chromosome location and interspecific collinearity were analyzed in order to gain better understanding of GOX gene family in plants. The expression profile of a GOX ortholog following biotic stress stimuli was investigated in Vigna unguiculata plants exhibiting different genetic backgrounds, in view of recent studies showing differential expression of GOX proteins during biotic stress in resistant cultivars of this species. Family-dependent evolutionary and structural divergence were observed among distinct GOX genes, with higher gene conservation verified among members of Fabaceae family. VuGOX1 is early modulated during incompatible interactions with CPSMV in Vigna unguiculata, showing relevance in rapid plant defense responses. High divergence verified among Fabaceae and Poaceae GOX orthologs might impact in functional divergence between these gene families. This comparative study provides a comprehensive picture of evolutionary and structural aspects of the GOX gene family in plants, as well as emphasizes the involvement of GOX orthologs in plant stress responses.