Integrated Lipidomic and Transcriptomic Analysis Reveals Phospholipid Changes in Somatic Embryos of Picea asperata in Response to Partial Desiccation

Abstract

Partial desiccation treatment (PDT) is an effective technology for promoting the germination and conversion of conifer somatic embryos (SEs). PDT, as a drought stress, induces intensive physiological responses in phospholipid metabolism, which are not well understood in the conifer SEs. Here, we integrated lipidomics, transcriptomics and proteomics analyses to reveal the molecular basis of lipid remodeling under PDT in Picea asperata SEs. Among the 82 lipid molecular species determined by mass spectrometry, phosphatidic acid (PA) had a significant effect after PDT and was the most critical lipid in the response to PDT. The transcriptomics results showed that multiple transcripts in the glycerolipid and glycerophospholipid metabolism pathways were differentially expressed, and these included five PLDα1 transcripts that catalyze the conversion of phosphatidylcholine (PC) to PA. Furthermore, the enzyme activity of this phospholipase D (PLD) was significantly enhanced in response to PDT, and PDT also significantly increased the protein level of PLDα1 (MA_10436582g0020). In addition, PA is a key factor in gibberellin, abscisic acid and ethylene signal transduction. One GDI1, one DELLA, three ABI1s, two SnRK2s, one CTR and 12 ERFs showed significantly differential expression between SEs before and after PDT in this study. Our data suggest that the observed increases in the PA contents might result from the activation of PLDα by PDT. PA not only affects the physical and chemical properties of the cell membrane but also participates in plant hormone signal transduction. Our work provides novel insight into the molecular mechanism through which PDT promotes the germination of SEs of coniferous tree species and fills the gap in the understanding of the mechanism of somatic embryo lipid remodeling in response to PDT.

Spatial specificity of metabolism regulation of abscisic acid-imposed seed germination inhibition in Korean pine (Pinus koraiensis sieb et zucc)

“…The maintenance of cell membrane stability and integrity is critical for controlling regular cell metabolism and physiological processes ( Ling et al., 2022 ). Glycerophospholipid is an important component of the cell membrane ( Calzada et al., 2016 ).…”

“…Relatively few investigations have attempted to characterize the role of ABA-mediated glycerophospholipid metabolism in seed germination so far. However, most studies have focused on the involvement of phosphatidic acids in ABA signal pathways, influencing the germination process ( Zhang et al., 2004 ; Ling et al., 2022 ).…”

Primary Metabolite Screening Shows Significant Differences between Embryogenic and Non-Embryogenic Callus of Tamarillo (Solanum betaceum Cav.)

“…Other studies have shown the importance of lipid content in SE in Cichorium sp. and Picea asperata [61,62], and in tamarillo somatic embryos [18], which could explain the importance of choline in the overall variance of the data.…”

Table_2.docx

“…The maintenance of cell membrane stability and integrity is critical for controlling regular cell metabolism and physiological processes (Ling et al, 2022). Glycerophospholipid is an important component of the cell membrane (Calzada et al, 2016).…”

“…Relatively few investigations have attempted to characterize the role of ABA-mediated glycerophospholipid metabolism in seed germination so far. However, most studies have focused on the involvement of phosphatidic acids in ABA signal pathways, influencing the germination process (Zhang et al, 2004;Ling et al, 2022).…”