A Chromosome-level Genome Assembly of the Peruvian Algarrobo (Neltuma Pallida) Provides Insights on Its Adaptation to Its Unique Ecological Niche

The dry forests of northern Peru are dominated by the legumous tree Neltuma pallida which is adapted to hot arid and semiarid conditions in the tropics. Despite having been successfully introduced in multiple other areas around the world, N. pallida is currently threatened in its native area, where it is invaluable for the dry forest ecosystem and human subsistence. A major tool for enhancing ecosystem conservation and understanding the adaptive properties of N. pallida to dry forest ecosystems is the construction of a reference genome sequence. Here, we report on a high-quality reference genome for N. pallida. The final genome assembly size is 403.7 Mb, consisting of 14 pseudochromosomes and 63 scaffolds with an N50 size of 26.2 Mb and a 34.3% GC content. Use of Benchmarking Universal Single Copy Orthologs revealed 99.2% complete orthologs. Long terminal repeat elements dominated the repetitive sequence content which was 51.2%. Genes were annotated using N. pallida transcripts, plant protein sequences, and ab initio predictions resulting in 22,409 protein-coding genes encoding 24,607 gene models. Comparative genomic analysis showed evidence of rapidly evolving gene families related to disease resistance, transcription factors, and signaling pathways. The chromosome-scale N. pallida reference genome will be a useful resource for understanding plant evolution in extreme and highly variable environments.