Prof. Xia Zhiqiang’s research team from Hainan University has deciphered and annotated the genome of macadamia (Macadamiaintegrifolia), with their findings

published in the journalTropical Plant.

Australia nut, also known as macadamia nut or Queensland nut, is from the tropical trees native to Australia. The nut consists of fat and protein which exceed 70% fat and 9% respectively and 8 kinds of amino acids essential to human health. Due to its crispy kernel and richness in unsaturated fatty acids, macadamia has become a highly prized health product and a must in New Year’s shopping list for many.

Prof. Xia’s team constructed a chromosome-level macadamia genome (792Mb Contig N50 1.9Mb) through the three-generation sequencing of “Gui Hot 1”, the earliest macadamia variety with independent intellectual property right in China. Besides, the team discovered 37,657 coding proteins through gene prediction from scratch and homologous protein comparison. Researchers conducted a gene family analysis on macadamia and 11 species and constructed a phylogenetic tree with single-copy genes. They found that the macadamia diverged from Tillandsia, a plant of the same family, about 71 million years ago. In addition, macadamia underwent a WGD (whole genome duplication) event about 41 million years ago. This study identified 120 members of the GELP (GDSL-type lipase) gene family and determined their locations on 14 chromosomes.

The findings of this study provide new resources for macadamia’s genomics research and molecular marker breeding, and bring more opportunities to its future genetic and evolutionary research. Besides, its genomic information will help to elucidate the evolutionary process of the Sandero ophthalmicus species and further analyze its physiological and morphological diversity, revealing the significant role of macadamia in its evolution.