New insights into phenotypic heterogeneity for the distinct lipid accumulation of Schizochytrium sp. H016

Abstract

Background Schizochytrium sp. is a marine heterotrophic protist and an important sustainable resource for high value-added docosahexaenoic acid in the future. The production of different phenotypes during the continuous subculture of Schizochytrium sp. results in a serious reduction in lipid yield and complicates the used of this strain in scientific research and industrial production. Hence, obtaining an improved understanding of the phenotypic differences and molecular mechanisms underlying the cell-to-cell heterogeneity of Schizochytrium sp. is necessary. Results After continuous culture passage, Schizochytrium sp. H016 differentiated into two subpopulations with different morphologies and showed decreased capacity for lipid production. The presence of cell subpopulations with degraded lipid droplets led to a substantial decrease in overall lipid yield. Here, a rapid screening strategy based on fluorescence-activated cell sorting was proposed to classify and isolate subpopulations quickly in accordance with their lipid-producing capability. The final biomass and lipid yield of the subpopulation with high cell lipid content (i.e., H016-H) were 38.83 and 17.22 g/L, respectively, which were 2.07- and 5.38-fold higher than those of the subpopulation with low lipid content (i.e., H016-L), respectively. Subsequently, time‑resolved transcriptome analysis was performed to elucidate the mechanism of phenotypic heterogeneity in different subpopulations. Results showed that the expression of genes related to the cell cycle and lipid degradation was significantly upregulated in H016-L, whereas the metabolic pathways related to fatty acid synthesis and glyceride accumulation were remarkably upregulated in H016-H. Conclusion This study innovatively used flow cytometry combined with transcriptome technology to provide new insights into the phenotypic heterogeneity of different cell subpopulations of Schizochytrium sp. Furthermore, these results lay a strong foundation for guiding the breeding of oleaginous microorganisms with high lipid contents.

A phospholipid:diacylglycerol acyltransferase is involved in the regulation of phospholipids homeostasis in oleaginous Aurantiochytrium sp.

“…1 A). NR is widely used to characterize the neutral lipids [ 20 ], and thus we inferred that TAG was synthesized in cells carrying PDAT. Subsequently, thin-layer chromatography (TLC) was performed to detect the lipid profile, and as anticipated, TAG was detected in cells carrying PDAT (Fig.…”

Diverse mechanisms of bioproduction heterogeneity in fermentation and their control strategies

“…This phenomenon plays a vital role in bacteria persistence, bet-hedging, adaptation to environmental changes, division of labor, and biological diversity, ensuring population-level fitness and survival (Eldar & Elowitz, 2010 ; Ackermann, 2015 ; Evans & Zhang, 2020 ). In the realm of microbial bioproduction, the prevalence of heterogeneity has been extensively documented across diverse bioconversion systems (Mustafi et al., 2012 ; Pigou & Morchain, 2015 ; Xiao et al., 2016 ; Wang et al., 2020 ; Cao et al., 2021 ; Bao et al., 2022 ; Tague et al., 2023 ).…”

Transcriptome analysis of malate-induced Schizochytrium sp. FJU-512 reveals a novel pathway for biosynthesis of docosahexaenoic acid with enhanced expression of genes responsible for acetyl-CoA and NADPH accumulation

“…occurs under limited nitrogen supply ( Heggeset et al, 2019 ), and DHA accumulations in Schizochytrium sp. accompany with phenotypic heterogeneity ( Bao et al, 2022 ). However, little is known about transcriptome variations in response to the addition of different levels of malate for DHA synthesis in Schizochytrium sp.…”