Coordinated Lipid Mobilization during Seed Development and Germination in Peanut (Arachis hypogaea L.)

Peanut (Arachis hypogaea L.) is
one of the most important oil crops in the world due to its lipid-rich
seeds. Lipid accumulation and degradation play crucial roles in peanut
seed maturation and seedling establishment, respectively. Here, we
utilized lipidomics and transcriptomics to comprehensively identify
lipids and the associated functional genes that are important in the
development and germination processes of a large-seed peanut variety.
A total of 332 lipids were identified; triacylglycerols (TAGs) and
diacylglycerols were the most abundant during seed maturation, constituting
70.43 and 16.11%, respectively, of the total lipids. Significant alterations
in lipid profiles were observed throughout seed maturation and germination.
Notably, TAG (18:1/18:1/18:2) and (18:1/18:2/18:2) peaked at 23386.63
and 23392.43 nmol/g, respectively, at the final stage of seed development.
Levels of hydroxylated TAGs (HO-TAGs) increased significantly during
the initial stage of germination. Accumulation patterns revealed an
inverse relationship between free fatty acids and TAGs. Lipid degradation
was determined to be regulated by diacylglycerol acyltransferase,
triacylglycerol lipase, and associated transcription factors, predominantly
yielding oleic acid, linoleic acid, and linolenic acid. Collectively,
the results of this study provide valuable insights into lipid dynamics
during the development and germination of large-seed peanuts, gene
resources, and guiding future research into lipid accumulation in
an economically important crop.