Structure-Function Analysis of STRUBBELIG, an Arabidopsis Atypical Receptor-Like Kinase Involved in Tissue Morphogenesis

Tissue morphogenesis in plants requires the coordination of cellular behavior across clonally distinct histogenic layers. The underlying signaling mechanisms are presently being unraveled and are known to include the cell surface leucine-rich repeat receptor-like kinase STRUBBELIG in Arabidopsis. To understand better its mode of action an extensive structure-function analysis of STRUBBELIG was performed. The phenotypes of 20 EMS and T-DNA-induced strubbelig alleles were assessed and homology modeling was applied to rationalize their possible effects on STRUBBELIG protein structure. The analysis was complemented by phenotypic, cell biological, and pharmacological investigations of a strubbelig null allele carrying genomic rescue constructs encoding fusions between various mutated STRUBBELIG proteins and GFP. The results indicate that STRUBBELIG accepts quite some sequence variation, reveal the biological importance for the STRUBBELIG N-capping domain, and reinforce the notion that kinase activity is not essential for its function in vivo. Furthermore, individual protein domains of STRUBBELIG cannot be related to specific STRUBBELIG-dependent biological processes suggesting that process specificity is mediated by factors acting together with or downstream of STRUBBELIG. In addition, the evidence indicates that biogenesis of a functional STRUBBELIG receptor is subject to endoplasmic reticulum-mediated quality control, and that an MG132-sensitive process regulates its stability. Finally, STRUBBELIG and the receptor-like kinase gene ERECTA interact synergistically in the control of internode length. The data provide genetic and molecular insight into how STRUBBELIG regulates intercellular communication in tissue morphogenesis

Pisces, Anegada Bay protected area, Buenos Aires Province, Argentina

We provide the first list of marine fish from Anegada Bay, a coastal protected area in Buenos AiresProvince. Fish records were obtained from gillnets and recreational fishery captures. Thirty seven speciesbelonging to 29 families and 18 orders were identified. The most numerous order was Perciformes witheight families and 10 species. Odontesthes argentinensis, Micropogonias furnieri, Cynoscion guatucupa andMustelus schmitti were verified in all sampling sites and the last two were the most represented either in theexperimental fishing and recreational captures. Presence of Lagocephalus laevigatus extended the so far knownrange distribution of this fish species, representing the southernmost records in Argentinean coastal waters.The fish fauna composition from Anegada Bay could be considered as from a transitional zone