Biology subjects

Vahabi, K.

Publications and source records attributed to Vahabi, K..

3 recordsLinked to original sources

bioRxiv2024

Metabolome and transcriptome profiling of root chicory provide insights into laticifer development and specialized metabolism

Chicory roots produce inulin, a dietary fiber, as well as large quantities of bitter sesquiterpene lactones (STLs), which have valuable biological activities. In an effort to understand the compartmentalization of metabolism within chicory roots and the molecular basis of the development of laticifers that produce the chicory latex, we performed metabolomics and transcriptomics profiling. GC-MS and LC-MS identified a total of 22 580 features of which 135 were differentially abundant between cell types. Further analysis indicated that the major STLs accumulated primarily in the latex. Gene expression of known STL pathway genes indicates a compartmentalization of the biosynthesis across multiple tissues, with implications regarding the trafficking of pathway intermediates. Phytohormone measurements and gene expression analysis point to a major role for jasmonate signaling in the development and differentiation of laticifers. Furthermore, inulin accumulates mostly outside the laticifers but expression of inulin metabolic genes also point to a complex distribution and trafficking of inulin or inulin precursors across different root compartments. Altogether, the data presented here constitute a unique resource to investigate several biological processes in chicory roots, including laticifer development, STL biosynthesis and transport and inulin biosynthesis regulation. Significance statementA combination of transcriptomics, targeted and untargeted metabolomics of different tissues of chicory roots was generated. These data constitute a resource basis for the investigation of various processes taking place in chicory taproots, including sesquiterpene lactone biosynthesis, laticifer development and inulin biosynthesis and trafficking.

plant biology↗

bioRxiv2023

The Arabidopsis Concert of Metabolic Acclimation to High Light Stress

In plants, exposure to high light irradiation induces various stress responses, which entail complex metabolic rearrangements. To systematically study such dynamic changes, we conducted time course experiments from 2 minutes to 72 hours with Arabidopsis thaliana plants exposed to high and control light conditions. We performed comparative metabolomics, transcriptomics, redox proteomics and stable isotope labelling on leaf rosettes. Our data analysis identifies a set of synchronous and successive responses that provide a deeper insight into well-orchestrated mechanisms contributing to high light acclimation. We observe a downregulation of genes encoding light harvesting proteins and a transient restriction of genes involved in linear electron flow through photosystem I. C4 acids, produced via anaplerotic routes, strongly accumulate under high light conditions. Redox homeostasis is tightly balanced by reduced NADPH production, enhanced subcellular redistribution of reducing equivalents across several subcellular compartments via photorespiration and activation of processes that quench reactive oxygen species. In this well-orchestrated network, methylerythritol 2,4-cyclodiphosphate, fulfills a dual function as intermediate of plastidic isoprenoid production and as a stress signal molecule.

plant biology↗

bioRxiv2022

DNA double strand breaks lead to de novo transcription and translation of damage-induced long RNAs in planta

DNA double strand breaks (DSBs) are lethal threats that need to be repaired. Although many of the proteins involved in the early steps of DSB repair have been characterized, recent reports indicate that damage induced long and small RNAs also play an important role in DSB repair. Here, using a Nicotiana benthamiana transgenic line originally designed as a reporter for targeted knock-ins, we show that DSBs generated by Cas9 induce the transcription of long stable RNAs (damage-induced long RNAs - dilRNAs) that are translated into proteins. Using an array of single guide RNAs we show that the initiation of transcription takes place in the vicinity of the DSB. Single strand DNA nicks are not able to induce transcription, showing that cis DNA damage-induced transcription is specific for DSBs. Our results support a model in which a default and early event in the processing of DSBs is transcription into RNA which, depending on the genomic and genic context, can undergo distinct fates, including translation into protein, degradation or production of small RNAs. Our results have general implications for understanding the role of transcription in the repair of DSBs and, reciprocally, reveal DSBs as yet another way to regulate gene expression.

molecular biology↗