Zare T, Paril JF, Barnett EM, Kaur P, Appels R, Ebert B, Roessner U, Fournier-Level A. Comparative genomics points to tandem duplications of SAD gene clusters as drivers of increased α-linolenic (ω-3) content in S. hispanica seeds.
THE PLANT GENOME 2024;
17:e20430. [PMID:
38339968 DOI:
10.1002/tpg2.20430]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/28/2023] [Accepted: 01/02/2024] [Indexed: 02/12/2024]
Abstract
Salvia hispanica L. (chia) is a source of abundant ω-3 polyunsaturated fatty acids (ω-3-PUFAs) that are highly beneficial to human health. The genomic basis for this accrued ω-3-PUFA content in this emerging crop was investigated through the assembly and comparative analysis of a chromosome-level reference genome for S. hispanica. The highly contiguous 321.5-Mbp genome assembly covering all six chromosomes enabled the identification of 32,922 protein-coding genes. Two whole-genome duplications (WGD) events were identified in the S. hispanica lineage. However, these WGD events could not be linked to the high α-linolenic acid (ALA, ω-3) accumulation in S. hispanica seeds based on phylogenomics. Instead, our analysis supports the hypothesis that evolutionary expansion through tandem duplications of specific lipid gene families, particularly the stearoyl-acyl carrier protein desaturase (ShSAD) gene family, is the main driver of the abundance of ω-3-PUFAs in S. hispanica seeds. The insights gained from the genomic analysis of S. hispanica will help establish a molecular breeding target that can be leveraged through genome editing techniques to increase ω-3 content in oil crops.
Collapse