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The hydraulic uplift is one of the disastrous failure patterns of the excavations in a coastal area. However, current practice and previous research failed to properly consider the strength of the soils to resist the uplift force from the underlain confined aquifer, partly due to poor understanding of the stress and deformation of the soils in the excavation. This study derived an analytical solution for the excess pore water pressure response in the basal clay based on a large excavation model. The method considered both the unloading effects due to the excavation and the effects of confined water pressure in the underlain confined aquifer. In addition, the effective stress and the deformation of the basal soil can also be calculated. A parametric study based on the solution identified three types of factors individually affecting the pore water pressure response, effective stress development, and the deformation of the basal soil. The findings of this study can provide insight reference for understanding the response of the basal soils in the excavation. (Authors.), The hydraulic uplift is one of the disastrous failure patterns of the excavations in a coastal area. However, current practice and previous research failed to properly consider the strength of the soils to resist the uplift force from the underlain confined aquifer, partly due to poor understanding of the stress and deformation of the soils in the excavation. This study derived an analytical solution for the excess pore water pressure response in the basal clay based on a large excavation model. The method considered both the unloading effects due to the excavation and the effects of confined water pressure in the underlain confined aquifer. In addition, the effective stress and the deformation of the basal soil can also be calculated. A parametric study based on the solution identified three types of factors individually affecting the pore water pressure response, effective stress development, and the deformation of the basal soil. The findings of this study can provide insight reference for understanding the response of the basal soils in the excavation. (Authors.)

Plants deploy cell-surface and intracellular leucine rich-repeat domain (LRR) immune receptors to detect pathogens(1). LRR receptor kinases and LRR receptor proteins at the plasma membrane recognize microorganism-derived molecules to elicit pattern-triggered immunity (PTI), whereas nucleotide-binding LRR proteins detect microbial effectors inside cells to confer effector-triggered immunity (ETI). Although PTI and ETI are initiated in different host cell compartments, they rely on the transcriptional activation of similar sets of genes(2), suggesting pathway convergence upstream of nuclear events. Here we report that PTI triggered by the Arabidopsis LRR receptor protein RLP23 requires signalling-competent dimers of the lipase-like proteins EDS1 and PAD4, and of ADR1 family helper nucleotide-binding LRRs, which are all components of ETI. The cell-surface LRR receptor kinase SOBIR1 links RLP23 with EDS1, PAD4 and ADR1 proteins, suggesting the formation of supramolecular complexes containing PTI receptors and transducers at the inner side of the plasma membrane. We detected similar evolutionary patterns in LRR receptor protein and nucleotide-binding LRR genes across Arabidopsis accessions; overall higher levels of variation in LRR receptor proteins than in LRR receptor kinases are consistent with distinct roles of these two receptor families in plant immunity. We propose that the EDS1-PAD4-ADR1 node is a convergence point for defence signalling cascades, activated by both surface-resident and intracellular LRR receptors, in conferring pathogen immunity.

Plant pattern recognition receptors (PRRs) facilitate recognition of microbial patterns and mediate activation of plant immunity. Arabidopsis thaliana RLP42 senses fungal endopolygalacturonases (PGs) and triggers plant defence through complex formation with SOBIR1 and SERK co-receptors. Here, we show that a conserved 9-amino-acid fragment pg9(At) within PGs is sufficient to activate RLP42-dependent plant immunity. Structure–function analysis reveals essential roles of amino acid residues within the RLP42 leucine-rich repeat and island domains for ligand binding and PRR complex assembly. Sensitivity to pg9(At), which is restricted to A. thaliana and exhibits scattered accession specificity, is unusual for known PRRs. Arabidopsis arenosa and Brassica rapa, two Brassicaceae species closely related to A. thaliana, respectively perceive immunogenic PG fragments pg20(Aa) and pg36(Bra), which are structurally distinct from pg9(At). Our study provides evidence for rapid evolution of polymorphic PG sensors with distinct pattern specificities within a single plant family.