Biology subjects

Cermanova, K.

Publications and source records attributed to Cermanova, K..

3 recordsLinked to original sources

bioRxiv2025

Xylan modifications in Populus that lead to increased growth

Xylem cells are surrounded by primary and secondary cell walls. Formation of primary walls is regulated by the cell wall integrity surveyance system, but it is unclear if the deposition of secondary walls is similarly regulated. To study this question, we introduced to aspen three different enzymes cleaving cell wall-localized xylan and we suppressed xylan synthase components either ubiquitously or specifically during secondary wall formation. When xylan was ubiquitously altered, 95% of lines showed reduced growth, whereas when it was altered during secondary wall deposition, 30% of lines grew better with the rest having no growth impairment, suggesting opposite effects of primary and secondary wall disturbances. To detect mechanism of growth stimulation by disturbed deposition of secondary wall, we analyzed changes in wood quality traits, chemistry, transcriptomics, metabolomics and hormonomics in transgenic lines. We found increased tension wood production, reduced S- and H-lignin, and changes in several metabolites in common in these lines. Remorin REM1.3 and NRL2 (NPH3 family) transcripts increased and changes in jasmonates, ABA and SA occurred in secondary wall-forming xylem suggesting their involvement in secondary wall integrity surveyance and signaling. The data indicate that a unique program mediates responses to secondary wall impairment that induces growth. HighlightDisturbance of the deposition of secondary walls that are responsible for the mechanical strength of plant bodies can increase growth with discrete changes in gene expression, hormone levels and metabolism.

plant biology↗

bioRxiv2025

Metabolic network divergence: polyamine and ethylene dynamics in Arabidopsis thaliana and Solanum lycopersicum

Polyamines are ubiquitously present in all living organisms. In plants, together with phytohormone ethylene, their metabolism plays a crucial role in plant stress and ontogenesis. We have evaluated differences in the responses of model plants Arabidopsis thaliana and Solanum lycopersicum to abiotic stresses and metabolic modulators based on key metabolite levels. Previous approaches have often focused separately on either polyamines, amino acids, or ethylene precursors. As these pathways are directly interconnected, their simultaneous evaluation can significantly impact our understanding of their core mechanisms. We have therefore developed a novel and validated liquid chromatography - tandem mass spectrometry based method, enabling quantification of fourteen compounds: the amino acids L-arginine, L-citrulline, L-ornithine; biogenic amines N-acetyl-L-ornithine and agmatine; the polyamines putrescine, spermidine, spermine, thermospermine, N-acetylputrescine, cadaverine, homospermidine; together with methionine and 1-aminocyclopropane-1-carboxylic acid, serving as key non-volatile precursors of ethylene. Our analysis revealed distinct metabolic responses between Arabidopsis and tomato, highlighted by species-specific differences in polyamine metabolism and ethylene precursors dynamics. Drought and salinity stresses triggered fundamentally different metabolic adjustments, with drought consistently inducing higher metabolite levels and spermine showing stress-specific responses. Metabolic inhibitor treatments with aminoguanidine and L-norvaline revealed further divergencies, mainly demonstrated as significant variations in ethylene precursor levels. For all approaches, Arabidopsis displayed more pronounced metabolic fluctuations compared to tomato. These results provide direct insights into contrasting metabolic plasticity and the interconnected roles of polyamines, amino acids, and ethylene precursors in plant responses and adaptations.

plant biology↗

bioRxiv2024

Modification of xylan in secondary walls alters cell wall biosynthesis and wood formation programs

Wood of broad-leaf tree species is a valued source of renewable biomass for biorefinery and a target for genetic improvement efforts to reduce its recalcitrance. Glucuronoxylan (GX) plays a key role in recalcitrance through its interactions with cellulose and lignin. To reduce recalcitrance, we modified wood GX by expressing GH10 and GH11 endoxylanases from Aspergillus nidulans in hybrid aspen (Populus tremula L. x tremuloides Michx.) and targeting the enzymes to cell wall. The xylanases reduced tree height, modified cambial activity by increasing phloem and reducing xylem production, and reduced secondary wall deposition. Xylan molecular weight was decreased, and the spacing between acetyl and MeGlcA side chains was reduced in transgenic lines. The transgenic trees produced hypolignified xylem having thin secondary walls and deformed vessels. Glucose yields of enzymatic saccharification without pretreatment almost doubled indicating decreased recalcitrance. The transcriptomics, hormonomics and metabolomics data provided evidence for activation of cytokinin and ethylene signaling pathways, decrease in ABA levels, transcriptional suppression of lignification and a subset of secondary wall biosynthetic program, including xylan glucuronidation and acetylation machinery. Several candidate genes for perception of impairment in xylan integrity were detected. These candidates could provide a new target for uncoupling negative growth effects from reduced recalcitrance. In conclusion, our study supports the hypothesis that xylan modification generates intrinsic signals and evokes novel pathways regulating tree growth and secondary wall biosynthesis.

plant biology↗