[Genome-wide identification of PfLACS in Perilla frutescens and functional analysis of PfLACS1 mediating lipid synthesis].

Perilla frutescens (L.) Britt. is a characteristic oil crop rich in n-3 polyunsaturated fatty acids in its seeds, holding significant potential for development and utilization. Long-chain acyl-CoA synthetase (LACS) plays a crucial regulatory role in plant lipid metabolism by activating free fatty acids into fatty acyl-CoA. In this study, to deeply analyze the functional characterization of the LACS gene in perilla lipid synthesis and storage, PfLACS sequences were identified from the genomic and transcriptomic data of P. frutescens. Omics tools were employed to analyze their sequence characteristics, gene structures, and phylogenetic relationships. The activity of PfLACS1 was evaluated via the LACS-deficient strain YB525, and the function of PfLACS1 in lipid synthesis was analyzed through genetic transformation in Saccharomyces cerevisiae and tobacco, as well as transient transformation in perilla cotyledons. A total of 12 PfLACS gene family members were identified and classified into five subfamilies based on sequence characteristics. Members within the same subfamily exhibited similar gene structures and conserved motifs in terms of type and number. The secondary structures of PfLACS were predominantly composed of α-helices and random coils. Transcriptome sequencing analysis revealed that 12 PfLACS were differentially expressed in developing perilla seeds, with PfLACS1 showing the highest expression level in seeds. Subcellular localization analysis indicated that PfLACS1 was localized to the endoplasmic reticulum. Yeast complementation assays confirmed that PfLACS1 could restore the functional deficiency in the LACS-deficient yeast strain YB525 and exhibited LACS activity. The results of heterologous expression indicated that overexpression of PfLACS1 led to a significant increase in total lipid content in both yeast and tobacco, accompanied by elevated levels of C16:1 and C18:1. Transient infection assays in perilla cotyledons further confirmed that overexpression of PfLACS1 significantly enhanced total lipid content. This study preliminarily confirms that PfLACS1 is involved in the activation of free fatty acids (especially C16 and C18) and fatty acid-related lipid metabolic processes, providing a theoretical basis for the genetic improvement and breeding of new varieties in P. frutescens and other oil-rich plants.