Biology subjects

Collakova, E.

Publications and source records attributed to Collakova, E..

4 recordsLinked to original sources

bioRxiv2022

Elicitors of plant defense induce the accumulation of amino acids that suppress both bacterial virulence and growth

Plant immunity relies on the perception of Microbe-Associate Molecular Patterns (MAMPs) from invading microbes to induce defense responses that suppress attempted infections. It has been proposed that MAMP-triggered immunity (MTI) suppresses bacterial infections by suppressing the onset of bacterial virulence. However, the mechanisms by which plants exert this action are poorly understood. Here we uncover that MAMP-perception in Arabidopsis induces the accumulation of free amino acids (AA) in a salicylic acid (SA) dependent manner. When co-infiltrated with Glutamine and Serine, two of the MAMP-induced highly accumulating amino acids, Pseudomonas syringae pv. tomato DC3000 expressed low levels of virulence genes and failed to produce robust infections in otherwise susceptible plants. When applied exogenously, Glutamine and Serine suppressed bacterial virulence and bacterial growth directly without the need for MAMP-perception and SA-signaling, bypassing MAMP-elicited defense. In addition, an increased level of endogenous Glutamine in the leaf apoplast of a gain-of-function mutant of Glutamine Dumper-1 rescued the partially compromised bacterial virulence and growth suppressing phenotype of the SA-induced deficient-2 (sid2) mutant. Our data suggest that MTI suppresses bacterial infections by the direct suppressing effect of accumulating amino acids on the onset of bacterial virulence.

plant biology↗

bioRxiv2021

Detailed characterization of the UMAMITs provides insight into their evolution, functional properties as amino acid transporters and role in the plant

Amino acid transporters play a critical role in distributing amino acids within the cell compartments and between the plant organs. Despite this importance, relatively few amino acid transporter genes have been characterized and their role elucidated with certainty. Two main families of proteins encode amino acid transporters in plants: the Amino Acid-Polyamine-Organocation superfamily, containing mostly importers, and the Usually Multiple Acids Move In and out Transporter family, apparently encoding exporters, totaling about 100 genes in Arabidopsis alone. Knowledge on UMAMITs is scarce, focused on six Arabidopsis genes and a handful of genes from other species. To get insight into the role of the members of this family and provide data to be used for future characterization, we studied the evolution of the UMAMITs in plants, and determined the functional properties, the structure, and the localization of the 44 Arabidopsis UMAMITs. Our analysis showed that the AtUMAMIT are essentially localized at the tonoplast or the plasma membrane, and that most of them are able to export amino acids from the cytosol, confirming a role in intra- and inter-cellular amino acid transport. As an example, this set of data was used to hypothesize the role of a few AtUMAMITs in the plant and the cell.

plant biology↗

bioRxiv2020

Induction of GLUTAMINE DUMPER1 reveals a link between amino acid export, abscisic acid, and immune responses

Amino acid homeostasis in plants is finely tuned to match developmental needs and response to adverse environments. Over-expression of the single-transmembrane domain protein GLUTAMINE DUMPER1 (GDU1) leads to increased amino acid export, reduced growth and constitutive induction of immune responses. We used an inducible gene expression system to tease apart the primary and secondary effects caused by GDU1, and demonstrated that the primary effect is increasing amino acid export, followed by increased amino acid content and abscisic acid (ABA) response, and a subsequent activation of defense responses. The GDU1-mediated hypersensitivity to ABA partially depended on the E3 ubiquitin ligase LOSS-OF-GDU1 2 (LOG2), a known GDU1 interactor. More importantly, the lysine catabolite pipecolic acid played a pivotal role in the GDU1-induced defense responses. This work unravels a novel relationship between amino acid transport, ABA and defense responses, potentially mediated by the GDU1-LOG2 complex, critical for understanding how plants respond to amino acid imbalance. ONE SENTENCE SUMMARYGenetically induced disturbance of amino acid homeostasis sequentially triggers responses to abiotic stresses and plant defenses to pathogens in Arabidopsis through undefined sensing mechanisms

plant biology↗

bioRxiv2017

SANe: The Seed Active Network For Mining Transcriptional Regulatory Programs of Seed Development

Developing seeds undergo coordinated physiological and morphological changes crucial for development of the embryo, dormancy and germination. The metabolic changes that occur during seed development are regulated by interconnected network of Transcription Factors (TFs) that regulate gene expression in a spatiotemporal manner. The complexity of these networks is such that the TFs that play key regulatory roles during seed development are largely unknown. In this study, we created a genome-scale regulatory network dedicated to describing regulation of biological processes within various compartments and developmental stages of Arabidopsis seeds. Differential network analysis revealed key TFs that rewire their targeting patterns specifically during seed development, many of which were already known, and a few novel ones that we verified experimentally. Our method shows that a high-resolution tissue-specific transcriptome dataset can be accurately modeled as a functional regulatory network predictive of related TFs. We provide an easy to use webtool using which researchers can upload a newly generated transcriptome and identify key TFs important to their dataset as well as gauge their regulatory effect on phenotypes observed in the experiment. We refer to this network as Seed Active Network (SANe) and made it accessible at https://plantstress-pereira.uark.edu/SANe/. We anticipate SANe will facilitate the discovery of TFs yet unknown for their involvement in seed related metabolic pathways and provide an interface to generate new hypothesis for experimentation.

bioinformatics↗