Loss of self-incompatibility (SI) in Arabidopsis thaliana was accompanied by inactivation of genes required for SI, including S-LOCUS RECEPTOR KINASE (SRK) and S-LOCUS CYSTEINE-RICH PROTEIN (SCR), coadapted genes that constitute the SI specificity-determining S haplotype. Arabidopsis accessions are polymorphic for CSRK and CSCR, but it is unknown if the species harbors structurally different S haplotypes, either representing relics of ancestral functional and structurally heteromorphic S haplotypes or resulting from decay concomitant with or subsequent to the switch to self-fertility. We cloned and sequenced the S haplotype from C24, in which self-fertility is due solely to S locus inactivation, and show that this haplotype was produced by interhaplotypic recombination. The highly divergent organization and sequence of the C24 and Columbia-0 (Col-0) S haplotypes demonstrate that the A. thaliana S locus underwent extensive structural remodeling in conjunction with a relaxation of selective pressures that once preserved the integrity and linkage of coadapted SRK and SCR alleles. Additional evidence for this process was obtained by assaying 70 accessions for the presence of C24-or Col-0-specific sequences. Furthermore, analysis of SRK and SCR polymorphisms in these accessions argues against the occurrence of a selective sweep of a particular allele of SCR, as previously proposed.

The self-incompatibility (SI) system of the Brassicaceae is based on allele-specific interactions among haplotypes of the S locus. In all tested self-incompatible Brassicaceae, the S haplotype encompasses two linked genes, one encoding the S-locus receptor kinase (SRK), a transmembrane kinase displayed at the surface of stigma epidermal cells, and the other encoding its ligand, the S-locus cysteine-rich (SCR) protein, which is localized in the pollen coat. Transfer of the two genes to self-fertile Arabidopsis thaliana allowed the establishment of robust SI in several accessions, indicating that the signaling cascade triggered by this receptor-ligand interaction and the resulting inhibition of "self" pollen by the stigma have been maintained in extant A. thaliana. Based on studies in Brassica species, the membrane-tethered kinase MLPK, the ARM repeatcontaining U-box protein ARC1, and the exocyst subunit Exo70A1 have been proposed to function as components of an SI signaling cascade. Here we tested the role of these molecules in the SI response of A. thaliana SRK-SCR plants. We show that the A. thaliana ARC1 ortholog is a highly decayed pseudogene. We also show that, unlike reports in Brassica, inactivation of the MLPK ortholog AtAPK1b and overexpression of Exo70A1 neither abolish nor weaken SI in A. thaliana SRK-SCR plants. These results do not support a role for these molecules in the SI response of A. thaliana.receptor signaling | S locus receptor kinase

Sodium metal batteries (SMBs) are attracting extensive attention for large‐scale energy storage due to the abundant reserves and low cost of sodium. However, the inevitable side reactions and uncontrollable dendrite growth in SMBs result in a continuous deterioration of the electrochemical performance and induce serious safety concerns, which severely restrict its practical application in the future. Among various improvement strategies, the 3D confinement strategy demonstrates great potential for stabilizing the Na anode owing to its optimized ion/electron transportation, lower deposition overpotential, and superior structural stability. Herein, first, the recent progress in SMBs which use the 3D confinement strategy to improve the electrochemical cycling stability of Na anode are outlined, and the potential regulation mechanism, including the transport/deposition behavior of Na+, interface engineering, and some advanced characterization techniques, are summarized. Furthermore, critical challenges and new perspectives are emphasized in detail. This review provides a deeper insight to enable construct ion of more comprehensive and effective Na metal anodes for advanced SMBs.

Neoagaro-oligosaccharides derived from agarose have been demonstrated to possess a variety of biological activities, such as anti-bacteria and anti-oxidative activities. In this study, we mainly explored the inhibitory effects and the mechanisms of neoagaro-oligosaccharide monomers against LPS-induced inflammatory responses in mouse macrophage RAW264.7 cells. The results indicated that neoagaro-oligosaccharide monomers especially neoagarotetraose could significantly reduce the production and release of NO in LPS-induced macrophages. Neoagarotetraose significantly suppressed the expression and secretion of inducible nitric oxide synthase (iNOS) and proinflammatory cytokines such as TNF-α and IL-6. The inhibition mechanisms may be associated with the inhibition of the activation of p38MAPK, Ras/MEK/ERK and NF-κB signaling pathways. Thus, neoagarotetraose may attenuate the inflammatory responses through downregulating the MAPK and NF-κB signaling pathways in LPS-stimulated macrophages. In summary, the marine-derived neoagaro-oligosaccharide monomers merit further investigation as novel anti-inflammation agents in the future.