Chromosome-level genome assembly of Tamarindus indica provides new insights into the evolution of triterpenes and tartaric acid biosynthetic pathway

Tamarindus indica is the sole member of the genus Tamarindus of the Leguminosae family. It is a multipurpose horticultural plant, with every part of the plant finding importance in food, medicine, and other industries. To gain an understanding of genome structure and evolution, we reported the first high-quality genome assembly of T. indica anchored to 12 chromosomes with an N50 of 56.6 Mb. Supported by comprehensive transcriptome data, we reported 48,867 protein-coding genes. Through phylogenetic and evolutionary analysis, we uncovered an independent whole-genome duplication event in T. indica and highlighted the expression divergence of segmentally duplicated genes and their role in the better adaptivity of the plant. Further, we observed a high expansion of the terpene cyclase mutase (oxidosqualene cyclase, OSCs) gene family and identified nine OSCs and their putative functions in T. indica. In addition, by employing integrated genomic, transcriptomic, and metabolomic analysis, we identified the putative L-Idonate dehydrogenase (L-IDH) gene in T. indica and provided evidence about its possible role in the accumulation of high tartaric acid content in this plant. Our study thus provides an important resource for future genetic and biotechnological studies to understand essential pathways and assist breeding programs for trait enhancements.