title: A rice antisense SPK transformant that lacks the accumulation of seed storage substances shows no correlation between sucrose concentration in phloem sap and demand for carbon sources in the sink organs.
abstract: Rice SPK is a calmodulin-like domain protein kinase specific to immature seeds and promotes the degradation of sucrose. Therefore, antisense SPK transformants showed a defective production of storage starch, but accumulated sucrose in watery seeds. Despite a reduced sink strength, no difference was found in the sucrose concentration in phloem sap of the transformants and wild-type plants, which increased after floral organ induction to levels greater than 500 mM. However, sucrose was detected at relatively lower levels in the watery seed sap. These results suggest that sucrose content in the phloem is regulated independently from the demand for carbon sources in the sink organs.
authors.affiliation: Department of Biological Science and Technology, Tissue Engineering Research Center, Tokyo University of Science, Yamazaki 2641, Noda, 278-8510 Japan. shimadah@rs.noda.tus.ac.jp
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Koishihara
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Saito
authors.forename: Yuki
authors.initials: Y
authors.lastname: Arashima
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Furukawa
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D001693:Biological Transport, Active / Q000235:genetics; D002244:Carbon / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000235:genetics*; D012275:Oryza / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism*; D014170:Transformation, Genetic / Q000235:genetics*
chemical_list: D016376:Oligonucleotides, Antisense; D013395:Sucrose; D002244:Carbon; D013213:Starch; D011494:Protein Kinases