An international team has sequenced the first high-quality reference genome of the argan (Argania spinosa), an endemic tree of Moroccothanks to advanced scientific techniques in a study published in the journal Nature.
The research was led by the National Institute of Agronomic Research of Morocco with Mohammed V University, the International Center for Saline Agriculture in Dubai, Texas Tech University and the International Center for Agricultural Research in Arid Zones (ICARDA).
The genome, of a specimen “TAGUERTE (S7P2)” in Taguert, in the southern province of Tiznit, will promote the conservation and genetic improvement of this tree for greater productivity and resistance.
Morocco’s current agricultural strategy, called the Green Generation Plan 2020-2030, seeks to double argan oil production to 10,000 tons, plant 50,000 new hectares and rehabilitate another 400,000 hectares where the tree is already planted.
The research team used PacBio HiFi techniques for long DNA reads, Hi-C for chromosome structure, and RNA-seq of leaves, roots, and seeds to annotate genes.
PacBio HiFi is a technique for reading DNA in long pieces with near-perfect accuracy (over 99.9%) to determine the exact order of nucleotides, while Hi-C is a technique that shows how DNA is folded and organized in 3D inside the cell.
However, RNA-seq analyzes the RNA (active copy of genes) from leaves, roots, and seeds to identify which genes are active where, and what combinations the cell uses to function. All these techniques allowed us to build an almost complete genetic map of argan.
The argan, the only representative of the Sapotaceae family in North Africa and protected by UNESCO on the slopes of the High and Anti Atlas of Morocco, provides food fruits, forage and oil from its seeds, key against desertification.
Their populations have been declining since the 19th century due to climate change, overexploitation and demographic pressure.