Genome-wide characterization of invertases in Arabica coffee and its progenitors reveals putative genes involved in fruit development

In plant physiological processes, invertases act by irreversibly degrading sucrose into hexoses, which actively contribute to plant growth and development. Few invertase genes have been characterized in Coffea, and consequently, the role of these enzymes in coffee plant development is not well understood. The present study conducted a genome-wide characterization of invertases in Arabica coffee and its diploid progenitors. A total of 65 invertase genes were identified, with 28 in C. arabica (CaINV), 18 in C. canephora (CcINV), and 19 in C. eugenioides (CeINV), with polyploidization being the primary cause of the expansion of the CaINV gene family. Synteny analyses and chromosomal mapping showed that the CaINV genes are mainly derived from C. eugenioides. The cis-acting elements suggested the involvement of invertase genes in three main categories: growth and development, responses to biotic and abiotic stress, and hormonal response. Transcriptome analyses showed that, except for the neutral/alkaline invertase gene CaN/AINV1, all invertase genes of C. arabica and C. canephora were expressed at different stages of fruit development, some constitutively and others conditionally. Although CaN/AINV1 was not expressed in the evaluated tissues, the presence of two GCN4 cis-elements suggests its involvement in specific processes in tissues or stages not analyzed in this study. Our results open many avenues for future studies in Coffea, especially for C. arabica and C. canephora, which are economically most significant and exhibit particularities regarding disease resistance, tolerance to abiotic stresses, and fruit chemical composition.