Draft genome of the peanut A-genome progenitor (Arachis duranensis) provides insights into geocarpy, oil biosynthesis, and allergens
Abstract
Peanut or groundnut (Arachis hypogaea L.), a legume of South American
origin, has high seed oil content (45–56%) and is a staple crop in
semiarid tropical and subtropical regions, partially because of drought
tolerance conferred by its geocarpic reproductive strategy. We present
a draft genome of the peanut A-genome progenitor, Arachis
duranensis, and 50,324 protein-coding gene models. Patterns of gene
duplication suggest the peanut lineage has been affected by at least
three polyploidizations since the origin of eudicots. Resequencing of
synthetic Arachis tetraploids reveals extensive gene conversion in
only three seed-to-seed generations since their formation by human
hands, indicating that this process begins virtually immediately following
polyploid formation. Expansion of some specific gene families
suggests roles in the unusual subterranean fructification of Arachis.
For example, the S1Fa-like transcription factor family has 126 Arachis
members, in contrast to no more than five members in other examined
plant species, and is more highly expressed in roots and etiolated
seedlings than green leaves. The A. duranensis genome provides a
major source of candidate genes for fructification, oil biosynthesis,
and allergens, expanding knowledge of understudied areas of plant
biology and human health impacts of plants, informing peanut genetic
improvement and aiding deeper sequencing of Arachis diversity