Project description:The casparian strip serves as a crucial diffusion barrier in the endodermis, playing a vital role in controlling the flow of substances between the root and its external environment. Here, we observed that when the casparian strip is absent, bacteria can accumulate abundantly on the roots. To investigate the impact of this bacterial accumulation on the root indued by casparian strip deficiency , we inoculated Col-0 and sgn3 myb36 roots with CHA0 in a hydroponic system. Ultimately, we found that the bacterial accumulation on the roots, resulting from the absence of the Casparian strip, strongly induces the immune response of the roots. This indicates that the casparian strip plays an important role in regulating the interaction between the root and microorganisms.
Project description:Whole Genome Duplication (WGD) events occurred frequently during land plant evolution and their long term benefits to neo-functionalization of genes and speciation is well known (Baduel et al., 2018). However short term benefits, important for the establishment of a new population, are more difficult to observe until Chao et al., 2013 described a fitness advantage under high salinity. Additionally shoot K levels were higher in neo-tetraploids, an important feature since K uptake becomes increasingly more difficult on highly saline soil. The molecular basis for these phenotypes was not known. Here we analyze neo-tetraploid Arabidopsis thaliana plants using RNAseq and ICP-MS to evaluate the effect of mutations and ploidy on the gene expression and shoot ionome. We are able to show that neo-tetraploid plants induce low-potassium (K) signaling to increase their shoot K content. However, we also show that this low-K signaling is distinct form previously studied, externally applied low-K signaling. In this way, we are able to identify new components of the K homeostasis network, which are required to regulate K demand. Additionally we are able to show that while individual components of the K uptake system are not sufficient to increase shoot K, a loss of root hairs abolished the ploidy K phenotype (PPP) as does a defective Casparian strip. Root hairs are the site of entry of K into the root and neo-tetraploids increase their root hair length and density (RHI) to facilitate their higher K demand. The Casparian strip on the other hand enables higher K concentration in the stele of the root, which is required for the increased K content in neo-tetraploids.
Project description:Whole Genome Duplication (WGD) events occurred frequently during land plant evolution and their long term benefits to neo-functionalization of genes and speciation is well known (Baduel et al., 2018). However short term benefits, important for the establishment of a new population, are more difficult to observe until Chao et al., 2013 described a fitness advantage under high salinity. Additionally shoot K levels were higher in neo-tetraploids, an important feature since K uptake becomes increasingly more difficult on highly saline soil. The molecular basis for these phenotypes was not known. Here we analyze neo-tetraploid Arabidopsis thaliana plants using RNAseq and ICP-MS to evaluate the effect of mutations and ploidy on the gene expression and shoot ionome. We are able to show that neo-tetraploid plants induce low-potassium (K) signaling to increase their shoot K content. However, we also show that this low-K signaling is distinct form previously studied, externally applied low-K signaling. In this way, we are able to identify new components of the K homeostasis network, which are required to regulate K demand. Additionally we are able to show that while individual components of the K uptake system are not sufficient to increase shoot K, a loss of root hairs abolished the ploidy K phenotype (PPP) as does a defective Casparian strip. Root hairs are the site of entry of K into the root and neo-tetraploids increase their root hair length and density (RHI) to facilitate their higher K demand. The Casparian strip on the other hand enables higher K concentration in the stele of the root, which is required for the increased K content in neo-tetraploids.
Project description:The Casparian strip constitutes a physical diffusion barrier formed by the polar deposition of lignin in the root endodermis. The polar deposition of lignin is thought to be mediated by the scaffolding activity of membrane bound Casparian Strip domain proteins (CASPs) and the dirigent domain-containing protein Enhanced Suberin1 (ESB1). Here, we show that the endodermis-specific receptor-like kinase (ERK1), is part of this machinery, playing an essential role in the localization of CASP proteins and in the deposition of lignin, which ultimately are required for the formation of afunctional Casparian strip. ERK1 is localized to the cytoplasm and nucleus of the endodermis, and is part of a signalling pathway that implicates the circadian clock regulator Time for Coffee (TIC). In addition, we found that loss of ERK1 and TIC disrupts the Casparian strip organisation and alters composition of the root microbiome.
Project description:Stem cells are defined by their ability to self-renew and produce daughter cells that proliferate and mature. These maturing cells transition from a proliferative state to a terminal state through the process of differentiation. In the Arabidopsis thaliana root the transcription factors SCARECROW and SHORTROOT regulate specification of the bi-potent stem cell that gives rise to the cortical and endodermal progenitors. Subsequent progenitor proliferation and differentiation generates mature endodermis, marked by the Casparian Strip: a cell wall modification that prevents ion diffusion into and out of the vasculature. We identified a transcription factor, MYB36 that regulates the transition from proliferation to differentiation in the endodermis. We show that SCARECROW directly activates MYB36 expression, which in turn directly regulates essential Casparian Strip formation genes. In addition, MYB36 represses extra divisions within the endodermis. Our results demonstrate that MYB36 is a critical positive regulator of differentiation and negative regulator of cell proliferation.
Project description:Stem cells are defined by their ability to self-renew and produce daughter cells that proliferate and mature. These maturing cells transition from a proliferative state to a terminal state through the process of differentiation. In the Arabidopsis thaliana root the transcription factors SCARECROW and SHORTROOT regulate specification of the bi-potent stem cell that gives rise to the cortical and endodermal progenitors. Subsequent progenitor proliferation and differentiation generates mature endodermis, marked by the Casparian Strip: a cell wall modification that prevents ion diffusion into and out of the vasculature. We identified a transcription factor, MYB36 that regulates the transition from proliferation to differentiation in the endodermis. We show that SCARECROW directly activates MYB36 expression, which in turn directly regulates essential Casparian Strip formation genes. In addition, MYB36 represses extra divisions within the endodermis. Our results demonstrate that MYB36 is a critical positive regulator of differentiation and negative regulator of cell proliferation. 12 samples analyzed: 3 biological replicates each from 1) wild type (Col-0) whole root, 2) mutant (myb36-1) whole root, 3) wild type (Col-0) sorted endodermis, 4) mutant (myb36-1) sorted endodermis
Project description:Here we show that the CASPARIAN STRIP INTEGRITY FACTOR 2 peptide induces SCHENGEN3 (SGN3) receptor-kinase dependent transcriptional changes both in short-term (30 min) and long-term (480 min) transcriptional changes in roots of Arabidopsis thaliana. We deposit RNA-seq data of wildtype, sgn3, and cif1,2 with or without the CIF2 peptide treatment. Wildtype and cif1,2 presented large transcriptional changes, while the sgn3 receptor mutant showed almost no difference after the treatment.
Project description:Nitrate (NO3-) is crucial for optimal plant growth and development and often limits crop productivity at the low availability. In comparison with model plant Arabidopsis, the molecular mechanisms underlying NO3- acquisition and utilization remain largely unclear in maize. In particular, only a few genes have been exploited to improve nitrogen use efficiency (NUE). Here, we demonstrated that NO3--inducible ZmNRT1.1B (ZmNPF6.6) positively regulated NO3--dependent growth and NUE in maize. We showed that the tandem duplicated proteoform ZmNRT1.1C is irrelevant to maize seedling growth under nitrate supply, however, loss-of-function of ZmNRT1.1B significantly weakened plant growth under adequate NO3- supply in both hydroponic and field conditions. 15N-labeled NO3- absorption assay indicated that ZmNRT1.1B mediated high-affinity NO3--transport and root-to-shoot NO3- translocation. Furthermore, upon NO3- supply, ZmNRT1.1B promotes cytoplasmic-to-nuclear shuttling of ZmNLP3.1 (ZmNLP8), which co-regulates the expression of genes involved in NO3- response, cytokinin biosynthesis and carbon metabolism. Remarkably, overexpression of ZmNRT1.1B in modern maize hybrids improved grain yield under nitrogen (N) limiting fields. Taken together, our study revealed a crucial role of ZmNRT1.1B in high-affinity NO3- transport and signaling and offers valuable genetic resource for breeding nitrogen use efficient high-yield cultivars.
2023-04-25 | GSE227472 | GEO
Project description:RNA-seq on Casparian strip defective mutant roots in Lotus japonicus