Chromosomal-level genome of macadamia (<i>Macadamia integrifolia</i>)

Abstract

Macadamia from the family Proteaceae is a plant native to Australia and has long been favoured by people for its crispy and high nutritional and medicinal value. Here, the genome of GUIRE 1 (GR1), a highly heterozygous superior cultivar of macadamia nut, was sequenced and assembled using nanopore sequencing, and a 807-Mb genome (contig N50, 1.9 Mb; scaffold N50, 54.70 Mb) and 14 chromosomes were obtained. A total of 453 Mb (about 55.95%) repetitive sequences and 37,657 protein-coding genes were obtained by gene annotation and homologous protein comparison. Proteaceae diverged from Nelumbonaceae nearly 115.37 million years ago and from Rubiaceae about 140 million years ago. A genome-wide duplication (WGD) event occurred in macadamia 41 million years ago based on the WGD analysis. The functional enrichment analysis of <italic>M. integrifolia</italic>-specific gene families revealed their roles in signal transduction, protein phosphorylation, protein binding, and defense response. Here, a highly heterozygous genome of <italic>M. integrifolia</italic> was unlocked to provide a database for breeding and molecular mechanism research.