title: Spermidine synthase genes are essential for survival of Arabidopsis.
abstract: The cellular polyamines putrescine, spermidine, and spermine are ubiquitous in nature and have been implicated in a wide range of growth and developmental processes. There is little information, however, on mutant plants or animals defective in the synthesis of polyamines. The Arabidopsis genome has two genes encoding spermidine synthase, SPDS1 and SPDS2. In this paper, we describe T-DNA insertion mutants of both of these genes. While each mutant allele shows normal growth, spds1-1 spds2-1 double-mutant seeds are abnormally shrunken and they have embryos that are arrested morphologically at the heart-torpedo transition stage. These seeds contain significantly reduced levels of spermidine and high levels of its precursor, putrescine. The embryo lethal phenotype of spds1-1 spds2-1 is complemented by the wild-type SPDS1 gene. In addition, we observed a nearly identical seed phenotype among an F2 seed population from the cross between the spds2-1 allele and SPDS1 RNA interference transgenic lines. These data provide the first genetic evidence indicating a critical role of the spermidine synthase in plant embryo development.
authors.affiliation: Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Imai
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuyama
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Hanzawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Akiyama
authors.forename: Masanori
authors.initials: M
authors.lastname: Tamaoki
authors.forename: Hikaru
authors.initials: H
authors.lastname: Saji
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Shirano
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Kato
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hayashi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shibata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tabata
authors.forename: Yoshibumi
authors.initials: Y
authors.lastname: Komeda
authors.forename: Taku
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D016254:Mutagenesis, Insertional; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000254:growth & development; D011073:Polyamines / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D011436:Spermidine Synthase / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers; D011073:Polyamines; D018749:RNA, Plant; D011436:Spermidine Synthase