Perilla frutescens is well known for its high α-linolenic acid (ALA) accumulation in seeds and medicinal values as well as a source of edible and general-purpose oils. However, the regulatory mechanisms of the biosynthesis of fatty acid in its seeds remain poorly understood due to the lacking of sequenced genome. For better understanding the regulation of lipid metabolism and further increase its oil content or modify oil composition, time-course transcriptome and lipid composition analyses were performed. Analysis of fatty acid content and composition showed that the α-linolenic acid and oleic acid accumulated rapidly from 5 DAF to 15 DAF and then kept relatively stable. However, the amount of palmitic acid and linoleic acid decreased quickly from 5 DAF to 15DAF. No significant variation of stearic acid content was observed from 5 DAF to 25DAF. Our transcriptome data analyses revealed that 110,176 unigenes were generated from six seed libraries at 5, 10, 20 DAF. Of these, 53 (31 up, 22 down) and 653 (259 up, 394 down) genes showed temporal and differentially expression during the seed development in 5 DAF vs 10 DAF, 20 vs 10 DAF, respectively. The differentially expressed genes were annotated and found to be involved in distinct functional categories and metabolic pathways. Deep mining of transcriptome data led to the identification of key genes involved in fatty acid and triacylglycerol biosynthesis and metabolism. Thirty seven members of transcription factor family AP2, B3 and NFYB putatively involved in oil synthesis and deposition were differentially expressed during seed development. The results of qRT-PCR for selected genes showed a strong positive correlation with the expression abundance measured in RNA-seq analysis. The present study provides valuable genomic resources for characterizing Perilla seed gene expression at the transcriptional level and will extend our understanding of the complex molecular and cellular events of oil biosynthesis and accumulation in oilseed crops.

Phosphatidylethanolamine-binding proteins (PEBP) family plays important roles in regulating plant flowering time and morphogenesis. However, geneme-wide identification and functional analysis of PEBP genes in the rigorous short-day plant Perilla frutescens (PfPEBP) have not been studied. In this study, 10 PfPEBP were identified and divided into three subfamilies based on their phylogenetic relationships: FT-like, TFL1-like and MFT-like. Gene structure analysis showed that all PfPEBP genes contain 4 exons and 3 introns. Motifs DPDxP and GIHR essential for anion-binding activity are highly conserved in PfPEBP. A large number of light-responsive elements were detected in promoter regions of PfPEBP. Gene expression of PfFT1 exhibited a diurnal rhythm. It was highly expressed in leaves under the short-day photoperiod, but higher in flowers and seeds under the long-day photoperiod. Overexpression of PfFT1 in Arabidopsis thaliana not only promoted early flowering of Col-0 or Ler, but also rescued the late flowering phenotype of ft-1 mutant. We concluded that PfFT1 promotes early flowering by regulating the expression of flowering-related genes AtAP1, AtLFY, AtFUL and AtSOC1. In conclusion, our results provided valuable information for elucidating the functions of PfPEBP in P. frutescens and shed light on the promoting effect of PfFT1 on flowering.

The thermo-sensitive genic male sterility (TGMS) of Brassica napus facilitates reproductive researches and hybrid seed production. Considering the complexity and little information about the molecular mechanism involved in B. napus TGMS, comparative transcriptomic analyses were peroformed for the sterile (160S-MS) and fertile (160S-MF) flowers to identify potential crucial genes and pathways associated with TGMS. In total, RNA-seq analysis showed that 2202 genes (561 up-regulated and 1641 down-regulated) were significantly differentially expressed in the fertile flowers of 160S-MF at 25 °C when compared the sterile flower of 160S-MS at 15 °C. Detailed analysis revealed that expression changes in genes encoding heat shock proteins, antioxidant, skeleton protein, GTPase and calmodulin might be involved in TGMS of B. napus. Moreover, gene expression of some key members in plant hormone signaling pathways, such as auxin, gibberellins, jasmonic acid, abscisic acid, brassinosteroid signalings, were significantly surppressed in the flowers of 160S, suggesting that these genes might be involved in the regulation in B. napus TGMS. Here, we also found that transcription factor MADS, NFY, HSF, MYB/C and WRKY might play a crucial role in male fertility under the high temperature condition. High temperature can significant affect gene expression in the flowers. The findings in the current study improve our understanding of B. napus TGMS at the molecular level and also provide an effective foundation for male fertility researches in other important economic crops.