title: Characterization of a sugarcane (Saccharum spp.) gene homolog to the brassinosteroid insensitive1-associated receptor kinase 1 that is associated to sugar content.
abstract: The present article reports on the characterization of ScBAK1, a leucine-rich repeat receptor-like kinase from sugarcane (Saccharum spp.), expressed predominantly in bundle-sheath cells of the mature leaf and potentially involved in cellular signaling cascades mediated by high levels of sugar in this organ. In this report, it was shown that the ScBAK1 sequence was similar to the brassinosteroid insensitive1-associated receptor kinase1 (BAK1). The putative cytoplasmatic domain of ScBAK1 contains all the amino acids characteristic of protein kinases, and the extracellular domain contains five leucine-rich repeats and a putative leucine zipper. Transcripts of ScBAK1 were almost undetectable in sugarcane roots or in any other sink tissue, but accumulated abundantly in the mature leaves. The ScBAK1 expression was higher in the higher sugar content individuals from a population segregating for sugar content throughout the growing season. In situ hybridization in sugarcane leaves showed that the ScBAK1 mRNA accumulated at much higher levels in bundle-sheath cells than in mesophyll cells. In addition, using biolistic bombardment of onion epidermal cells, it was shown that ScBAK1-GFP fusions were localized in the plasma membrane as predicted for a receptor kinase. All together, the present data indicate that ScBAK1 might be a receptor involved in the regulation of specific processes in bundle-sheath cells and in sucrose synthesis in mature sugarcane leaves.
authors.affiliation: Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, SP, Brazil. shinapes@unicamp.br
authors.forename: Renato
authors.initials: R
authors.lastname: Vicentini
authors.forename: Juliana de Maria
authors.initials: Jde M
authors.lastname: Felix
authors.forename: Marcelo Carnier
authors.initials: MC
authors.lastname: Dornelas
authors.forename: Marcelo
authors.initials: M
authors.lastname: Menossi
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D031786:Saccharum / Q000235:genetics* / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D013395:Sucrose; D017346:Protein Serine-Threonine Kinases