Arabidopsis diacylglycerol acyltransferase1 mutants require fatty acid desaturation for normal seed development.
Plant J
; 119(2): 916-926, 2024 Jul.
Article
in En
| MEDLINE
| ID: mdl-38762880
ABSTRACT
Diacylglycerol acyltransferase1 (DGAT1) is the major enzyme that synthesizes triacylglycerols (TAG) during Arabidopsis seed development. Mutant dgat1 seeds possess low oil content in addition to a high polyunsaturated fatty acid (PUFA) composition. Two genes encoding endoplasmic reticulum localized desaturase enzymes, fatty acid desaturase2 (FAD2) and fatty acid desaturase3 (FAD3), were upregulated in both dgat1-1 and dgat1-2 developing seeds. Crosses between both dgat1 mutant alleles and fad2-1 failed to generate plants homozygous for both dgat1 and fad2. Reciprocal crosses with wild-type plants demonstrated that both male and female dgat1 fad2 gametophytes were viable. Siliques from DGAT1/dgat1-1 fad2-1/fad2-1 and dgat1-1/dgat1-1 FAD2/fad2-1 possessed abnormal looking seeds that were arrested in the torpedo growth stage. Approximately 25% of the seeds exhibited this arrested phenotype, genetically consistent with them possessing the double homozygous dgat1 fad2 genotype. In contrast, double homozygous dgat1-1 fad3-2 mutant plants were viable. Seeds from these plants possessed higher levels of 182 while their fatty acid content was lower than dgat1 mutant controls. The results are consistent with a model where in the absence of DGAT1 activity, desaturation of fatty acids by FAD2 becomes essential to provide PUFA substrates for phospholipiddiacylglycerol acyltransferase (PDAT) to synthesize TAG. In a dgat1 fad2 mutant, seed development is aborted because TAG is unable to be synthesized by either DGAT1 or PDAT.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Seeds
/
Arabidopsis
/
Gene Expression Regulation, Plant
/
Arabidopsis Proteins
/
Diacylglycerol O-Acyltransferase
/
Fatty Acid Desaturases
/
Mutation
Language:
En
Journal:
Plant J
Journal subject:
BIOLOGIA MOLECULAR
/
BOTANICA
Year:
2024
Type:
Article
Affiliation country:
United States