Biology subjects

Koprivova, A.

Publications and source records attributed to Koprivova, A..

3 recordsLinked to original sources

bioRxiv2021

Glutathione contributes to plant defense against parasitic cyst nematodes

Cyst nematodes (CNs) are an important group of root-infecting sedentary endoparasites that severely damage many crop plants worldwide. An infective CN juvenile enters the hosts roots and migrates towards the vascular cylinder, where it induces the formation of syncytial feeding cells, which nourish the CN throughout its parasitic stages. Here, we examined the role of glutathione (L-{gamma}-glutamyl-L-cysteinylglycine, GSH) in Arabidopsis thaliana upon infection with the CN Heterodera schachtii. Arabidopsis lines with mutations pad2, cad2, or zir1 in the glutamate-cysteine ligase (GSH1) gene, which encodes the first enzyme in the glutathione biosynthetic pathway, displayed enhanced CN susceptibility, but susceptibility was reduced for rax1, another GSH1 allele. Biochemical analysis revealed differentially altered thiol levels in these mutants that was independent of nematode infection. All GSH-deficient mutants exhibited impaired activation of defense marker genes as well as genes for biosynthesis of the antimicrobial compound camalexin early in infection. Further analysis revealed a link between glutathione-mediated plant susceptibility to CN infection and the production of camalexin upon nematode infection. These results suggest that GSH levels affects plant susceptibility to CN by fine-tuning the balance between the cellular redox environment and the production of compounds related to defense against infection.

plant biology↗

bioRxiv2021

Rhizobiales commensal bacteria promote Arabidopsis thaliana root growth via host sulfated peptide pathway

Root-associated commensal bacteria that belong to the order Rhizobiales, which also contains symbiotic and pathogenic bacteria, promote primary root growth of Arabidopsis thaliana. However, the molecular mechanism underlying this root growth promotion (RGP) activity remained unclear. Here, we conducted a transcriptomic analysis of A. thaliana roots inoculated with root-associated commensal bacteria of Rhizobiales and sister lineages and revealed common and strain/lineage-specific transcriptional response, possibly mediated by WRKY and ANAC family of transcription factors. We showed that the observed common response was also partly triggered by a wide range of non-pathogenic bacteria, fungi, and a multikingdom synthetic community (SynCom). This response was characterized by a down-regulation of genes related to intracellular redox regulation, suggesting distinctive redox status between pathogenic and non-pathogenic interactions. By integrating with developmental and cell biological experiments, we identified a crucial role of TYROSYLPROTEIN SULFOTRANSFERASE (TPST) in Rhizobiales RGP. Conversely, none of the known TPST-dependent sulfated peptide pathways appeared to be required for this activity, suggesting an unidentified component in the protein sulfation pathway targeted by Rhizobiales RGP. Finally, we show that TPST is needed for RGP exerted by Rhizobiales but not Pseudomonadales isolates, delineating lineage-specific mechanisms to manipulate host root development.

plant biology↗

bioRxiv2020

Shoot-root interaction in control of camalexin exudation in Arabidopsis

Plants exude secondary metabolites from the roots to shape the composition and function of their microbiome. Many of these compounds are known for their anti-microbial activity and are part of the plant immunity, such as the indole-derived phytoalexin camalexin. Here we studied the dynamics of camalexin synthesis and exudation upon induction of Arabidopsis thaliana with a plant growth promotion bacteria Pseudomonas sp. CH267 or a bacterial pathogen Burkholderia glumae PG1. We show that while the camalexin accumulation and exudation is more rapidly but transiently induced upon interaction with the growth promoting strain, the pathogen induces a higher and more stable camalexin levels. The concentration of camalexin in shoots, roots and exudates is well correlated, triggering a question on the origin of the exuded camalexin. By combination of experiments with cut shoots and roots and grafting of wild type plant with mutants in camalexin synthesis we showed that while camalexin can be produced and released by both organs, in intact plant the exuded camalexin originates in the shoots. We show that camalexin synthesis in response to B. glumae PG1 is dependent on cooperation of four CYP71 genes and a loss of function of any of them reduces camalexin synthesis. In conclusion, camalexin synthesis seems to be controlled on a whole plant level and coordinated between shoots and roots.

plant biology↗