Genome-wide analysis of cellulose synthase gene superfamily in Tectona grandis L.f

This study aimed to explore Cellulose synthase gene superfamily of teak, and its evolutionary relationship with homologous genes of other woody species. The incidence of evolutionary events like gene duplication and gene loss, influence of the selection pressure, and consequent adaptive functional divergence of the duplicated TgCes gene were assessed alongside it’s role in wood coloration. This study identified 39 full-length non-redundant proteins belonging to CesA and Csl gene families. TgCesA and TgCsl proteins with Cellulose synthase domain repeats indicated tandem gene duplication and probable genetic variability, enabling local adaptation. Further, multi-domain protein (MYB-like DNA-binding domain and CesA domain) with maximum introns was also identified indicating gene fusion and formation of complex protein with novel functions. Phylogenetic analysis grouped the genes into seven subfamilies (CesA, CslA, CslC, CslD, CslE, CslG, and CslM) with each undergoing gene duplication and loss along their evolutionary history. Post-species gene duplications and probable neofunctionalization were identified in TgCesA and TgCsl gene families. Each subfamily was found to be under strong purifying selection with a few or no sites under positive selection. Functional divergence analysis further revealed site-specific selective constraints in CesA and Csl genes of the teak Cellulose synthase gene family. Furthermore, protein–protein interaction network analysis identified co-expression of Cellulose synthase gene with flavonoid 3′,5′-hydroxylase (F3′5′H, CYP75A), involved in the biosynthesis of xylem anthocyanin compounds, probably responsible for wood coloration. This study thus offers a foundation for future research in wood formation and wood property traits specific to teak and its provenances.