Biology subjects

Moravec, T.

Publications and source records attributed to Moravec, T..

4 recordsLinked to original sources

bioRxiv2026

Loss of PR1 function enhances Arabidopsis resistance to Botrytis cinerea

PATHOGENESIS-RELATED 1 (PR1) is one of the most widely used markers of salicylic acid (SA)-dependent plant immunity, yet its direct functional contribution to pathogen defence remains poorly understood. Here, we investigated the role of PR1 in Arabidopsis thaliana by analyzing a pr1 loss-of-function mutant challenged with bacterial and fungal pathogens and fumonisin B1 (FB1)-induced cell death. Notably, loss of PR1 led to markedly different responses to distinct pathogens; while it moderately increased susceptibility to the pathogenic bacterium Pseudomonas syringae, it substantially enhanced resistance to the necrotrophic fungus Botrytis cinerea, and the responses to the necrotroph Sclerotinia sclerotiorum remained unaltered. The pr1 mutant also displayed reduced spread of FB1-induced cell death, linking PR1 function to the promotion of stress-associated cell death. In line with the susceptibility changes, we observed the strongest PR1 accumulation and cell wall enrichment during B. cinerea infection using mCherry-tagged PR1 expressed under its endogenous promoter. Complementation with full-length PR1 and with a C-terminally truncated PR1 variant lacking the CAPE peptide restored wild-type susceptibility, whereas a non-cleavable PR1 variant did not. These results indicate that proteolytic processing at the CAPE cleavage motif, rather than the CAPE peptide itself, is required for PR1 function. Our data thus strongly suggest that PR1 may act as a susceptibility factor for necrotrophic pathogens by promoting host cell death.

Plant Biology↗

bioRxiv2023

Identification of watermelon genes involved in the ZYMV interaction through a miRNA bioinformatics analysis and characterization of ATRIP and RBOHB

Small RNA sequencing of healthy and ZYMV-infected watermelon (21 dpi) was performed and bioinformatics analysis identified 353 miRNAs from which 22 known and 331 new miRNAs. Important information about their precursors, their length, the loci of which they originated on watermelon genome are provided. The ZYMV genome could be a target for mir396a-3p, miR8706a, and miR1886i-5p from the miRbase, but none of them was identified in the watermelon miRNAome. Furthermore, watermelon miRNAome does not contain a miRNA targeting ZYMV genome with an expectation score [≤] 3.5. There were 34 resistance genes (CC-NBS-LRR, TIR-NBS-LRR, TIR-NBS) predicted as targets of 32 miRNAs in healthy watermelon. For nine differentially expressed miRNAs the respective target genes (10 in total) were bioinformatically predicted. For cla-new_miR307 (upregulated upon ZYMV infection) and cla-miR166h-3p (downregulated upon ZYMV infection) the targets were predicted to be ClaATRIP and ClaRBOHB, respectively, with ClaATRIP downregulated and ClaRBOHB upregulated upon ZYMV infection. ALSV-mediated VIGS of ClaATRIP rendered watermelon plants more resistant to ZYMV, whereas VIGS of ClaRBOHB resulted in higher levels of ZYMV titer in watermelon. These data suggest that ClaATRIP and ClaRBOHB are a susceptibility and resistant gene, respectively. Our results provide new insights in watermelon miRNAome and could propose new strategies for generating resistant watermelon to ZYMV. HighlightsO_LIBioinformatics analysis in healthy and ZYMV-infected watermelon plants gave 353 miRNAs, 22 known and 331 new. C_LIO_LIThe watermelon miRNAome identified in the present study does not appear to target the ZYMV genome (sense and reverse complement). C_LIO_LIThe differential expression of ten genes of watermelon in relation to ZYMV infection was validated. C_LIO_LIThe silencing of the two genes, ATRIP and RBOHB, through VIGS strongly suggested that ATRIP is a gene of susceptibility and RBOHB is a gene of resistance. C_LI

plant biology↗

bioRxiv2022

The FLOWERING LOCUS T LIKE 2-1 gene of Chenopodium triggers precocious flowering in Arabidopsis seedlings

The FLOWERING LOCUS T (FT) gene is the essential integrator of flowering regulatory pathways in angiosperms. The paralogs of the FT gene may perform antagonistic functions, as exemplified by BvFT1, that suppresses flowering in Beta vulgaris, unlike the paralogous activator BvFT2. The roles of FT genes in other amaranths were less investigated. Here, we transformed Arabidopsis thaliana with the FLOWERING LOCUS T like (FTL) genes of Chenopodium and found, that both FTL1 and FTL2-1 accelerated flowering, despite having been the homologs of the Beta vulgaris floral promoter and suppressor, respectively. The floral promotive effect of FTL2-1 was so strong that it caused lethality when overexpressed under the 35S promoter. FTL2-1 placed in inducible cassette accelerated flowering after the induction with methoxyphenozide. The occasional expression of FTL2-1 led to precocious flowering in some primary transformants even without chemical induction. After the FTL gene duplication in Amaranthaceae, the FTL1 copy maintained the role of floral activator. The second copy FTL2 underwent subsequent duplication and functional diversification, which enabled to control the onset of flowering in amaranths to adapt to variable environments. HIGHLIGHTThe FLOWERING LOCUS T like 2-1 (FTL 2-1) gene of Chenopodium acts as a strong activator of flowering in Arabidopsis, despite being a homolog of floral repressor BvFT1.

plant biology↗

bioRxiv2020

A role of DAO1 in oxidation of IAA amino acid conjugates revealed through metabolite, high throughput transcript and protein level analysis.

Auxin metabolism is, together with auxin transport, a key determinant of auxin signalling output in plant cells, yet details on the underlying mechanisms and factors involved are still largely unknown. Processes involved in the auxin metabolism are subject to regulation based on numerous signals, including auxin concentration itself. Altered auxin availability and the subsequent changes of auxin metabolite profiles can therefore elucidate the function and regulatory role of individual elements in the auxin metabolic machinery. After analysing auxin metabolism in auxin dependent tobacco BY-2 cell line grown in presence or absence of synthetic auxin 2,4-D we found that both conditions were similarly characterized by very low levels of endogenous indole-3-acetic acid (IAA) and its metabolites. However, metabolic profiling after exogenous application of IAA uncovered that the concentration of N-(2-oxindole-3-acetyl)-L-aspartic acid (oxIAA-Asp), the most abundantly formed auxin metabolite in the control culture, dramatically decreased in auxin-starved conditions. To describe the molecular mechanism behind this regulation, we analysed transcriptome and proteome changes caused by auxin starvation. While no changes in the expression of auxin biosynthetic machinery were observed, many genes related to auxin conjugation and degradation showed differential expression. Selected putative auxin glycosylating enzymes as well as members of the Gretchen Hagen 3 gene family involved in auxin amino acid conjugation showed both up- and down-regulation. Contrarily to that, all tobacco homologs of Arabidopsis thaliana DIOXYGENASE FOR AUXIN OXIDATION 1 (DAO1), known to be responsible for the formation of oxIAA from IAA, showed significant downregulation at both transcript and protein levels. To validate the role of DAO1 in auxin metabolism, we performed auxin metabolite profiling in BY-2 mutants carrying either siRNA-silenced or CRISPR-Cas9-mutated NtDAO1, as well as in dao1-1 Arabidopsis thaliana plants. Both mutants showed not only expectedly lower levels of oxIAA, but also significantly lower abundance of oxidated amino acid conjugates of IAA (oxIAA-Asp). Our results thus represent the first direct evidence on DAO1 activity on IAA amino acid conjugates. Statement of significanceHere we present an analysis of auxin metabolism on metabolite, transcript and protein levels in tobacco BY-2 cell line, collectively identifying oxidation of IAA amino acid conjugates as a new role of DIOXYGENASE FOR AUXIN OXIDATION 1 within an auxin-level-responsive metabolic system.

plant biology↗