Arabidopsis Type B Monogalactosyldiacylglycerol Synthase Genes Are Expressed during Pollen Tube Growth and Induced by Phosphate Starvation1
AUTOR(ES)
Kobayashi, Koichi
FONTE
The American Society for Plant Biologists
RESUMO
The galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) constitute the major glycolipids of the thylakoid membranes in chloroplasts. In Arabidopsis, the formation of MGDG is catalyzed by a family of three MGDG synthases, which are encoded by two types of genes, namely type A (atMGD1) and type B (atMGD2 and atMGD3). Although the roles of the type A enzyme have been intensively investigated in several plants, little is known about the contribution of type B enzymes to MGDG synthesis in planta. From our previous analyses, unique expression profiles of the three MGDG synthase genes were revealed in various organs and developmental stages. To characterize the expression profiles in more detail, we performed histochemical analysis of these genes using β-glucuronidase (GUS) assays in Arabidopsis. The expression of atMGD1::GUS was detected highly in all green tissues, whereas the expression of atMGD2::GUS and atMGD3::GUS was observed only in restricted parts, such as leaf tips. In addition, intense staining was detected in pollen grains of all transformants. We also detected GUS activity in the pollen tubes of atMGD2::GUS and atMGD3::GUS transformants grown in wild-type stigmas but not in atMGD1::GUS, suggesting that type B MGDG synthases may have roles during pollen germination and pollen tube growth. GUS analysis also revealed that expression of atMGD2 and atMGD3, but not atMGD1, are strongly induced during phosphate starvation, particularly in roots. Because only DGDG accumulates in roots during phosphate deprivation, type B MGDG synthases may be acting primarily to supply MGDG as a precursor for DGDG synthesis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=344540Documentos Relacionados
- Phosphite, an Analog of Phosphate, Suppresses the Coordinated Expression of Genes under Phosphate Starvation1
- Genome-Wide Identification of Genes Expressed in Arabidopsis Pistils Specifically along the Path of Pollen Tube Growth1[w]
- Gibberellins Are Required for Seed Development and Pollen Tube Growth in Arabidopsis
- Characterization of Anion Channels in the Plasma Membrane of Arabidopsis Epidermal Root Cells and the Identification of a Citrate-Permeable Channel Induced by Phosphate Starvation1
- Dynamic 1-Aminocyclopropane-1-Carboxylate-Synthase and -Oxidase Transcript Accumulation Patterns during Pollen Tube Growth in Tobacco Styles1