Sequencing Ancestor Diploid Genomes for Enhanced Genome Understanding and Peanut Improvement

Abstract

Cultivated peanut (Arachis hypogaea) is an allotetraploid with closely related subgenomes of a total size of ~2.7 Gb. To understand the genome of the cultivated peanut, it is prerequisite to know the genome organization of its diploid progenitors, A-genome—Arachis duranensis and B-genome—A. ipaensis. Two genome sequencing projects conducted sequencing and analysis of the genomes of diploid ancestors: (1) International Peanut Genome Initiative (IPGI) reported the sequencing of both A- and B-genomes; while (2) Diploid Progenitor Peanut Arachis Genome Sequencing Consortium (DPPAGSC) reported the sequencing of A-genome. IPGI study showed that these genomes are similar to cultivated peanut’s A- and B-subgenomes and used them to identify candidate disease resistance genes, to guide tetraploid transcript assemblies and to detect genetic exchange between cultivated peanut’s subgenomes thus providing evidence about direct descendant of the B subgenome in cultivated peanut. The DPPAGSC study, on the other hand, provided new insights into geocarpy, oil biosynthesis, and allergens in addition to providing information about evolution and polyploidization. These genome sequencing efforts have improved the understanding about the complex peanut genome and genome architecture which will play a very important role in peanut applied genomics and breeding.