Project description:In the lateral root repression system described by Babé et al. (2012), the first asymetric divisions of pericycle cells preceding lateral root formation are repressed during water deficit treatments. During an 8-hr long treatment, an 8-mm long root segment is formed where LR formation has been repressed. The experiment was designed to monitor changes in gene expression during early events of LR formation in barley using this LR repression system.
Project description:Previous studies have shown that methane (CH4) has promoting roles in the adventitious root (AR) and lateral root formation in plants. However, whether CH4 could trigger the bulblet formation in scale cutting of Lilium davidii var. unicolor has not been elucidated. To gain insight into the effect of CH4 on the bulblet formation, different concentrations (1%, 10%,50% and 100%) of methane-rich water (MRW) and distilled water were applied to treat the scale cuttings of Lilium. We observed that treatment with 100% MRW obviously induced the bulblet formation in scale cuttings. To explore the mechanism of CH4-induced the bulblet formation, the transcriptome of scales was analyzed. A total of 2078 differentially expressed genes (DEGs) were identified. The DEGs were classified into different metabolism pathways, especially phenylpropanoid biosynthesis, starch and sucrose metabolism and plant signal transduction. Of these, approximately 38 candidate DEGs involved in the plant signal transduction were further studied. In addition, the expression of AP2-ERF/ERF, WRKY, GRAS, ARF and NAC transcription factors were changed by MRW treatment, suggesting their potential involvement in bulblet formation. As for hormones, exogenous IAA, GA and ABA could indue the bulblet formation. Additional experiments suggested that MRW could increase the endogenous IAA, GA, and JA levels, but decrease the levels of ABA during bulblet formation, which showed that higher IAA, GA, JA levels and lower ABA content might facilitate bulblet formation. In addition, the levels of endogenous hormone were consistent with the expression level of genes involved in phytohormone signal transduction. Overall, this study has revealed that CH4 might improve the bulblet formation of cutting scales in Lilium by regulating the expression of genes related to phytohormone signal transduction and transcription factors, as well as by changing the endogenous hormone levels.
Project description:Optimum protein function and biochemical activity critically depends on water availability, because solvent thermodynamics drive protein folding and macromolecular interactions. Reciprocally, macromolecules restrict the movement of “structured” water molecules within their hydration layers, reducing the available “free” bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Within concentrated macromolecular solutions like the cytosol, we found modest changes in temperature greatly impact the water potential, and are counteracted by opposing changes in osmotic strength. Remarkably, this duality of temperature and osmotic strength allows simple manipulations of solvent thermodynamics to prevent cell death upon extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength that impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales, so we postulated the existence of a rapid compensatory response. We find this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically-disordered proteins. Formation or dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which in consequence is robustly buffered in the cytoplasm. Our results indicate biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function.