Nodule Organogenesis and Symbiotic Mutants of the Model Legume \u3ci\u3eLotus japonicus\u3c/i\u3e

A detailed microscopical analysis of the morphological features that distinguish different developmental stages of nodule organogenesis in wild-type Lotus japonicus ecotype Gifu B-129-S9 plants was performed, to provide the necessary framework for the evaluation of altered phenotypes of L. japonicus symbiotic mutants. Subsequently, chemical ethyl methanesulfonate (EMS) mutagenesis of L. japonicus was carried out. The analysis of approximately 3,000 M1 plants and their progeny yielded 20 stable L. japonicus symbiotic variants, consisting of at least 14 different symbiosis- associated loci or complementation groups. Moreover, a mutation affecting L. japonicus root development was identified that also conferred a hypernodulation response when a line carrying the corresponding allele (LjEMS102) was inoculated with rhizobia. The phenotype of the LjEMS102 line was characterized by the presence of nodule structures covering almost the entire root length (Nod++), and by a concomitant inhibition of both root and stem growth. A mutation in a single nuclear gene was shown to be responsible for both root and symbiotic phenotypes observed in the L. japonicus LjEMS102 line, suggesting that (a) common mechanism(s) regulating root development and nodule formation exists in legumes

Identification and Characterization of the Arabidopsis PHO1 Gene Involved in Phosphate Loading to the Xylem

The Arabidopsis mutant pho1 is deficient in the transfer of Pi from root epidermal and cortical cells to the xylem. The PHO1 gene was identified by a map-based cloning strategy. The N-terminal half of PHO1 is mainly hydrophilic, whereas the C-terminal half has six potential membrane-spanning domains. PHO1 shows no homology with any characterized solute transporter, including the family of H(+)-Pi cotransporters identified in plants and fungi. PHO1 shows highest homology with the Rcm1 mammalian receptor for xenotropic murine leukemia retroviruses and with the Saccharomyces cerevisiae Syg1 protein involved in the mating pheromone signal transduction pathway. PHO1 is expressed predominantly in the roots and is upregulated weakly under Pi stress. Studies with PHO1 promoter–β-glucuronidase constructs reveal predominant expression of the PHO1 promoter in the stelar cells of the root and the lower part of the hypocotyl. There also is β-glucuronidase staining of endodermal cells that are adjacent to the protoxylem vessels. The Arabidopsis genome contains 10 additional genes showing homology with PHO1. Thus, PHO1 defines a novel class of proteins involved in ion transport in plants

Stowage and Transport Optimization in Ship Planning

Abstract. We consider the ship planning problem at maritime container terminals where containers are loaded onto and discharged from ships using quay cranes. The container transport between the ships and the yard positions in the terminal is carried out by a fleet of straddle carriers. Based on a stowage plan provided by the shipping company, the dispatcher assigns containers to specified bay positions. Then, subject to operational and stability constraints, he schedules containers in order to avoid waiting times at the quay cranes. We propose an approach combining stowage planning and the selection of “good ” loading and transport sequences. For a just-in-time scheduling model, we present computational results based on real-world data of a German container terminal. Moreover, we discuss some real-time and online influences on the daily dispatch situation