Addition of methyl jasmonate and rutin hydrate at harvest time elicits lipid production in Scenedesmus

Microalgae are a sustainable source of lipids for industrial applications. In this study, we tested the effect of three chemical elicitors [chitosan, methyl jasmonate (MeJA), and flavonoids] on lipid accumulation in the microalga Scenedesmus. We analyzed the effect of different concentrations of these elicitors at different time points on growth rate and lipid production. We found that these elicitors did not have an adverse effect on the growth rate of Scenedesmus at different time points, by comparison with their respective controls. Among the three elicitors, MeJA at a low concentration (25 μL/L) was found to be effective at enhancing the lipid production in Scenedesmus when added at the time of harvest and allowed to react for 12 h, whereas flavonoid treatment, specifically at 0.5 mg/L, enhanced lipid production after 24 h. Fatty acid methyl ester analysis by GC–MS revealed no difference in lipid profile before or after chemical induction. Taken together, this comparative analysis highlights the potential of MeJA at a low concentrations to be effective at improving lipid productivity without altering the growth rate in Scenedesmus.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Secondary structure pattern and sequence conservation of FLZ domain.

<p>(A) Secondary structure conservation of FLZ domain. Red color indicates alpha helix and blue color indicates beta-sheet. Confidence gradient of secondary structure formation is given on the top. (B) Sequence logo of <i>Arabidopsis</i>, <i>Medicago,</i> poplar and rice FLZ domains showing amino acid conservation.</p

DUF581 Is Plant Specific FCS-Like Zinc Finger Involved in Protein-Protein Interaction

<div><p>Zinc fingers are a ubiquitous class of protein domain with considerable variation in structure and function. Zf-FCS is a highly diverged group of C₂-C₂ zinc finger which is present in animals, prokaryotes and viruses, but not in plants. In this study we identified that a plant specific domain of unknown function, DUF581 is a zf-FCS type zinc finger. Based on HMM-HMM comparison and signature motif similarity we named this domain as <u>F</u>CS-<u>L</u>ike <u>Z</u>inc finger (FLZ) domain. A genome wide survey identified that FLZ domain containing genes are bryophytic in origin and this gene family is expanded in spermatophytes. Expression analysis of selected <i>FLZ</i> gene family members of <i>A. thaliana</i> identified an overlapping expression pattern suggesting a possible redundancy in their function. Unlike the zf-FCS domain, the FLZ domain found to be highly conserved in sequence and structure. Using a combination of bioinformatic and protein-protein interaction tools, we identified that FLZ domain is involved in protein-protein interaction.</p></div

Schematic representation of domain organization in FLZ protein family.

<p>The FLZ proteins are scanned by InterProScan to identify conserved domains. <i>A. thaliana</i> FLZ1 is shown as a representative model for proteins which contain FLZ domain only. Proteins which possess other domains along with FLZ are also shown. The domains are abbreviated as follows, FLZ (FCS like zinc finger, PF04570), PPR (Pentatricopeptide Repeat, PF01535), Cupin (Cupin 1, PF00190), ICF (Ion channel family, PF00520), CND (Cyclic nucleotide-binding domain, PF00027) and DUF3354 (Domain of unknown function 3354, PF11834).</p

Sub-cellular localization of FLZ1 and PFA-DSP3 in onion epidermal cells.

<p>(A) Vector alone. (B) FLZ1. (C) PFA-DSP3. Left to right, YFP only, bright field, merged. FLZ1 is localized in both nucleus and cytoplasm while PFA-DSP3 is exclusively localized in nucleus. YFP were excited at 514 nm and emission was recorded at 530 nm.</p

Distribution of <i>FLZ</i> gene family in sequenced genomes.

<p>Distribution of <i>FLZ</i> gene family in sequenced genomes.</p

FLZ acts as the module for protein-protein interaction.

<p>(A) FLZ1 interacts with PFA-DSP3 and STH2 in Y2H. Murine p53 and SV40 large T-antigen interaction taken as positive control and p53 and lamin interaction is taken as negative control. (B) The deletion constructs of FLZ1, N-terminal (1–88 amino acids), FLZ (89–140 amino acids) and C-terminal (141–177 amino acids). (C) Y2H with deletion constructs of FLZ1 with PFA-DSP3 and STH2 showing FLZ is essential for their interaction. (D) And (E) beta-galactosidase activity of full length FLZ1 and deletion constructs interaction with PFA-DSP3 and STH2.</p

Comprehensive Evolutionary and Expression Analysis of FCS-Like Zinc finger Gene Family Yields Insights into Their Origin, Expansion and Divergence.

Plant evolution is characterized by frequent genome duplication events. Expansion of habitat resulted in the origin of many novel genes and genome duplication events which in turn resulted in the expansion of many regulatory gene families. The plant-specific FCS-Like Zinc finger (FLZ) gene family is characterized by the presence of a FCS-Like Zinc finger (FLZ) domain which mediates the protein-protein interaction. In this study, we identified that the expansion of FLZ gene family size in different species is correlated with ancestral and lineage-specific whole genome duplication events. The subsequent gene loss found to have a greater role in determining the size of this gene family in many species. However, genomic block duplications played the significant role in the expansion of FLZ gene family in some species. Comparison of Arabidopsis thaliana and Oryza sativa FLZ gene family revealed monocot and dicot specific evolutionary trends. The FLZ genes were found to be under high purifying selection. The spatiotemporal expression analyses of Arabidopsis thaliana FLZ gene family revealed that majority of the members are highly expressed in reproductive organs. FLZ genes were also found to be highly expressed during vegetative-to-reproductive phase transition which is correlated with the proposed role of this gene family in sugar signaling. The comparison of sequence, structural and expression features of duplicated genes identified lineage-specific redundancy and divergence. This extensive evolutionary analysis and expression analysis of Arabidopsis thaliana FLZ genes will pave the way for further functional analysis of FLZ genes

Genome-Wide Identification and Expression, Protein–Protein Interaction and Evolutionary Analysis of the Seed Plant-Specific BIG GRAIN and BIG GRAIN LIKE Gene Family

BIG GRAIN1 (BG1) is an auxin-regulated gene which functions in auxin pathway and positively regulates biomass, grain size and yield in rice. However, the evolutionary origin and divergence of these genes are still unknown. In this study, we found that BG genes are probably originated in seed plants. We also identified that seed plants evolved a class of BIG GRAIN LIKE (BGL) genes which share conserved middle and C-terminal motifs with BG. The BG genes were present in all monocot and eudicot species analyzed; however, the BGL genes were absent in few monocot lineages. Both BG and BGL were found to be serine-rich proteins; however, differences in expansion and rates of retention after whole genome duplication events were observed. Promoters of BG and BGL genes were found to be enriched with auxin-responsive elements and the Arabidopsis thaliana BG and BGL genes were found to be auxin-regulated. The auxin-induced expression of AthBG2 was found to be dependent on the conserved ARF17/19 module. Protein-protein interaction analysis identified that AthBG2 interact with regulators of splicing, transcription and chromatin remodeling. Taken together, this study provides interesting insights about BG and BGL genes and incentivizes future work in this gene family which has the potential to be used for crop manipulation

Expression analysis of <i>Arabidopsis thaliana FLZ</i> gene family in different developmental stages and tissues using real-time PCR.

<p><i>UBQ10</i> is used as endogenous control. The absolute expression is calculated from ΔCT value. Graphs represent average and error bars represent mean ± SD of two biological replicates with three technical replicates each. X axis represent samples and Y axis represent absolute expression value. Samples are abbreviated in graph is as follows, RS, radicle emerged; CS, cotyledon stage seedling; LS, 2 leaves stage seedling; MR, mature plant root; ML, mature bolts rosette leaf; FB, flower bud; FO, flower open; SS, silique small; SM, silique mature.</p