Genome-Wide Identification, Characterization, and Expression Analysis of Long-Chain Acyl-CoA Synthetases in Carya illinoinensis under Different Treatments

As crucial enzymes in the lipid metabolic network, long-chain acyl-CoA synthases (LACSs) are members of the acyl-activated enzyme superfamily and play a crucial role in epidermal wax synthesis, plant lipid anabolic metabolism, and stress tolerance. In this study, 11 pecan LACS genes were identified and categorized into five groups and located on nine chromosomes. The significant degree of conservation in the AtLACS and CiLACS protein sequences was demonstrated by multiple sequence alignment and conserved motif analysis. Cis-acting element analysis identified numerous stress-responsive and hormone-inducible elements in the promoter regions of CiLACS genes. The expression levels of CiLACS9 and CiLACS9-1 were considerably up-regulated under salt and drought stress, according to the qRT-RCR study. Treatment with ABA also led to increased expression levels of CiLACS1, CiLACS1-1, CiLACS2, and CiLACS9-1. Notably, CiLACS4, CiLACS4-1, CiLACS9, and CiLACS9-1 exhibited peak expression levels at 135 days after anthesis and are likely to have been crucial in the accumulation of seed kernel oil. Moreover, the CiLACS9 gene was shown to be located in the cytoplasm. These findings offer a theoretical framework for clarifying the roles of LACS genes in the processes of pecan kernel oil synthesis and response to abiotic stressors.