Biology subjects

Skirycz, A.

Publications and source records attributed to Skirycz, A..

27 records · Page 2Linked to original sources

bioRxiv2021

Identification and Functional Annotation of Long Intergenic Non-coding RNAs in the Brassicaceae

Long intergenic noncoding RNAs (lincRNAs) are a large yet enigmatic class of eukaryotic transcripts with critical biological functions. Despite the wealth of RNA-seq data available, lincRNA identification lags in the plant lineage. In addition, there is a need for a harmonized identification and annotation effort to enable cross-species functional and genomic comparisons. In this study we processed >24 Tbp of RNA-seq data from >16,000 experiments to identify ~130,000 lincRNAs in four Brassicaceae: Arabidopsis thaliana, Camelina sativa, Brassica rapa, and Eutrema salsugineum. We used Nanopore RNA-seq, transcriptome-wide structural information, peptide data, and epigenomic data to characterize these lincRNAs and identify functional motifs. We then used comparative genomic and transcriptomic approaches to highlight lincRNAs in our dataset with sequence or transcriptional evolutionary conservation, including lincRNAs transcribed adjacent to orthologous genes that display little sequence similarity and likely function as transcriptional regulators. Finally, we used guilt-by-association techniques to further classify these lincRNAs according to putative function. LincRNAs with Brassicaceae-conserved putative miRNA binding motifs, short ORFs, and whose expression is modulated by abiotic stress are a few of the annotations that will prioritize and guide future functional analyses.

genomics↗

bioRxiv2021

Association of the malate dehydrogenase-citrate synthase metabolon is modulated by intermediates of the Krebs tricarboxylic acid cycle

Mitochondrial malate dehydrogenase (MDH)-citrate synthase (CS) multi-enzyme complex is a part of the Krebs tricarboxylic acid (TCA) cycle metabolon which is enzyme machinery catalyzing sequential reactions without diffusion of reaction intermediates into a bulk matrix. This complex is assumed to be a dynamic structure involved in the regulation of the cycle by enhancing metabolic flux. Microscale Thermophoresis analysis of the porcine heart MDH-CS complex revealed that substrates of the MDH and CS reactions, NAD+ and acetyl-CoA, enhance complex association while products of the reactions, NADH and citrate, weaken the affinity of the complex. Oxaloacetate enhanced the interaction only when it was presented together with acetyl-CoA. Structural modeling using published CS structures suggested that the binding of these substrates can stabilize the closed format of CS which favors the MDH-CS association. Two other TCA cycle intermediates, ATP, and low pH also enhanced the association of the complex. These results suggest that dynamic formation of the MDH-CS multi-enzyme complex is modulated by metabolic factors responding to respiratory metabolism, and it may function in the feedback regulation of the cycle and adjacent metabolic pathways.

biochemistry↗

bioRxiv2021

The diversity of quinoa morphological traits and seed metabolic composition

Quinoa (Chenopodium quinoa Willd.) is an herbaceous annual crop of the amaranth family (Amaranthaceae). It is increasingly cultivated for its nutritious grains, which are rich in protein and essential amino acids, lipids, and minerals. Quinoa exhibits a high tolerance towards various abiotic stresses including drought and salinity, which supports its agricultural cultivation under climate change conditions. The use of quinoa grains is compromised by anti-nutritional saponins, a terpenoid class of secondary metabolites deposited in the seed coat; their removal before consumption requires extensive washing, an economically and environmentally unfavorable process; or their accumulation can be reduced through breeding. In this study, we analyzed the seed metabolomes, including amino acids, fatty acids, and saponins, from 471 quinoa cultivars, including two related species, by liquid chromatography - mass spectrometry. Additionally, we determined a large number of agronomic traits including biomass, flowering time, and seed yield. The results revealed considerable diversity between genotypes and provide a knowledge base for future breeding or genome editing of quinoa. O_TBL View this table: org.highwire.dtl.DTLVardef@160e784org.highwire.dtl.DTLVardef@ff8bd1org.highwire.dtl.DTLVardef@13446daorg.highwire.dtl.DTLVardef@11796eeorg.highwire.dtl.DTLVardef@1b607b8_HPS_FORMAT_FIGEXP M_TBL C_TBL

plant biology↗

bioRxiv2021

2',3'-cAMP treatment mimics abiotic stress response

The role of the RNA degradation product 2,3-cyclic adenosine monophosphate (2,3-cAMP) is poorly understood. Recent studies have identified 2,3-cAMP in plant material and determined its role in stress signaling. The level of 2,3-cAMP increases upon wounding, dark, and heat, and 2,3-cAMP by binding to an RNA-binding protein, Rbp47b, promotes stress granule (SG) assembly. To gain further mechanistic insight into 2,3-cAMP function, we used a multi-omics approach combining transcriptomics, metabolomics, and proteomics to dissect Arabidopsis response to 2,3-cAMP treatment. We demonstrated that 2,3-cAMP is metabolized into adenosine, suggesting that the well-known cyclic nucleotide-adenosine pathway from human cells might also exist in plants. Transcriptomic analysis revealed only minor overlap between 2,3-cAMP-and adenosine-treated plants, suggesting that these molecules act through independent mechanisms. Treatment with 2,3-cAMP changed the levels of hundreds of transcripts, proteins, and metabolites, many previously associated with plant stress responses including protein and RNA degradation products, glucosinolates, chaperones and SG components. Finally, we demonstrated that 2,3-cAMP treatment influences the movement of processing bodies, supporting the role of 2,3-cAMP in the formation and motility of membraneless organelles.

plant biology↗

bioRxiv2021

SLIMP: Supervised learning of metabolite-protein interactions from co-fractionation mass spectrometry data

Metabolite-protein interactions affect and shape diverse cellular processes. Yet, despite advances, approaches for identifying metabolite-protein interactions at a genome-wide scale are lacking. Here we present an approach termed SLIMP that predicts metabolite-protein interactions using supervised machine learning on features engineered from metabolic and proteomic profiles from a co-fractionation mass spectrometry-based technique. By applying SLIMP with gold standards, assembled from public databases, along with metabolic and proteomic data sets from multiple conditions and growth stages we predicted over 9,000 and 20,000 metabolite-protein interactions for Saccharomyces cerevisiae and Arabidopsis thaliana, respectively. Extensive comparative analyses corroborated the quality of the predictions from SLIMP with respect to widely-used performance measures (e.g. F1-score exceeding 0.8). SLIMP predicted novel targets of 2, 3 cyclic nucleotides and dipeptides, which we analysed comparatively between the two organisms. Finally, predicted interactions for the dipeptide Tyr-Asp in Arabidopsis and the dipeptide Ser-Leu in yeast were independently validated, opening the possibility for future applications of supervised machine learning approaches in this area of systems biology.

systems biology↗

bioRxiv2021

Manipulation of carotenoid metabolism stimulates biomass and stress tolerance in tomato

Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of Vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars simultaneously improved photosynthetic capacity and tolerance to various abiotic stresses (e.g., high light, salt, and drought), caused an up to 77% fruit yield increase and enhanced fruits provitamin A content and shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.

plant biology↗

bioRxiv2020

Hello darkness, my old friend: 3-Ketoacyl-Coenzyme A Synthase4 is a branch point in the regulation of triacylglycerol synthesis in Arabidopsis by re-channeling fatty acids under carbon starvation

Due to their sessile lifestyle, plants have evolved unique mechanisms to deal with environmental challenges. Under stress, plant lipids are important as alternative sources of carbon and energy when sugars or starch are limited. Here, we applied combined heat and darkness and extended darkness to a panel of [~] 300 Arabidopsis accessions to study lipid remodeling under carbon starvation. Natural allelic variation at 3-KETOACYL-COENZYME A SYNTHASE4 (KCS4), a gene encoding for an enzyme involved in very long chain fatty-acid (VLCFA) synthesis, underlies a differential accumulation of polyunsaturated triacylglycerols (puTAGs) under stress. Ectopic expression in yeast and plants proved that KCS4 is a functional enzyme localized in the ER with specificity for C22 and C24 saturated acyl-CoA. Allelic mutants and transient overexpression in planta revealed the differential role of KCS4 alleles in VLCFA synthesis and wax coverage, puTAG accumulation and biomass. Moreover, the region harboring KCS4 is under high selective pressure and allelic variation at KCS4 correlated with environmental parameters from the locales of Arabidopsis accessions. Our results provide evidence that KCS4 plays a decisive role in the subsequent fate of fatty acids released from chloroplast-membrane lipids under carbon starvation. This work sheds light on both plant response mechanisms and the evolutionary events shaping the lipidome under carbon starvation. One sentence summaryNatural variation at KCS4 underlies a differential accumulation of polyunsaturated triacylglycerols under carbon starvation, by acting as a regulatory branch point in the fate of fatty acids.

genetics↗

bioRxiv2020

Autophagy is responsible for the accumulation of proteogenic dipeptides in response to heat stress in Arabidopsis thaliana.

Proteogenic dipeptides are intermediates of proteolysis as well as an emerging class of small-molecule regulators with diverse and often dipeptide-specific functions. Herein, prompted by differential accumulation of dipeptides in a high-density Arabidopsis thaliana time-course stress experiment, we decided to pursue an identity of the proteolytic pathway responsible for the buildup of dipeptides under heat conditions. By querying dipeptide accumulation versus available transcript data, autophagy emerged as a top hit. To examine whether autophagy indeed contributes to the accumulation of dipeptides measured in response to heat stress, we characterized the loss-of-function mutants of crucial autophagy proteins to test whether interfering with autophagy would affect dipeptide accumulation in response to the heat treatment. This was indeed the case. This work implicates the involvement of autophagy in the accumulation of proteogenic dipeptides in response to heat stress in Arabidopsis.

biochemistry↗

bioRxiv2020

Arabidopsis REI-LIKE proteins activate ribosome biogenesis during cold acclimation

Arabidopsis REIL proteins are cytosolic ribosomal 60S-biogenesis factors. After shift to 10{degrees}C, reil mutants deplete and slowly replenish non-translating eukaryotic ribosome complexes of root tissue, while tightly controlling the balance of non-translating 40S- and 60S-subunits. Reil mutations compensate by hyper-accumulation of non-translating subunits at steady-state temperature; after cold-shift, a KCl-sensitive 80S sub-fraction remains depleted. We infer that Arabidopsis buffers fluctuating translation by pre-existing non-translating ribosomes before de novo synthesis meets temperature-induced demands. Reil1 reil2 double mutants accumulate 43S-preinitiation and pre-60S-maturation complexes and have altered paralog composition of ribosomal proteins in non-translating complexes. With few exceptions, e.g. RPL3B and RPL24C, these changes are not under transcriptional control. Our study suggests requirement of de novo synthesis of eukaryotic ribosomes for long-term cold acclimation, feedback control of NUC2 and eIF3C2 transcription and links new proteins, AT1G03250, AT5G60530, to plant ribosome biogenesis. We propose that Arabidopsis requires biosynthesis of specialized ribosomes for cold acclimation. Highlight of this studyREIL proteins affect paralog composition of eukaryotic ribosomes and suppress accumulation of 43S-preinitiation and pre-60S-maturation complexes, suggesting functions of ribosome heterogeneity and biogenesis in plant cold acclimation.

plant biology↗