The endophytic fungus Piriformospora indica stimulates the expression of nitrate reductase and the starch-degrading enzyme glucan-water dikinase in tobacco and Arabidopsis roots through a homeodomain transcription factor that binds to a conserved motif in their promoters.
Piriformospora indica, an endophytic fungus of the Sebacinaceae family, promotes growth of Arabidopsis and tobacco seedlings and stimulates nitrogen accumulation and the expression of the genes for nitrate reductase and the starch-degrading enzyme glucan-water dikinase (SEX1) in roots. Neither growth promotion nor stimulation of the two enzymes requires heterotrimeric G proteins. P. indica also stimulates the expression of the uidA gene under the control of the Arabidopsis nitrate reductase (Nia2) promoter in transgenic tobacco seedlings. At least two regions (-470/-439 and -103/-89) are important for Nia2 promoter activity in tobacco roots. One of the regions contains an element, ATGATAGATAAT, that binds to a homeodomain transcription factor in vitro. The message for this transcription factor is up-regulated by P. indica. The transcription factor also binds to a CTGATAGATCT segment in the SEX1 promoter in vitro. We propose that the growth-promoting effect initiated by P. indica is accompanied by a co-regulated stimulation of enzymes involved in nitrate and starch metabolisms.
Sherameti
Irena
I
Institute of General Botany and Plant Physiology, Friedrich Schiller University Jena, 07743 Jena, Germany.
Shahollari
Bationa
B
Venus
Yvonne
Y
Altschmied
Lothar
L
Varma
Ajit
A
Oelmüller
Ralf
R
D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D001487:Basidiomycota / Q000378:metabolism*; D015152:Blotting, Northern; D015153:Blotting, Western; D049109:Cell Proliferation; D018920:Coculture Techniques; D017931:DNA Primers / Q000737:chemistry; D019281:Dimerization; D019204:GTP-Binding Proteins / Q000737:chemistry; D015966:Gene Expression Regulation, Fungal; D018506:Gene Expression Regulation, Plant; D013058:Mass Spectrometry; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000096:biosynthesis* / Q000235:genetics; D009566:Nitrates / Q000737:chemistry; D020411:Oligonucleotide Array Sequence Analysis; D009841:Oligonucleotides / Q000737:chemistry / Q000494:pharmacology; D018517:Plant Roots / Q000201:enzymology*; D030821:Plants, Genetically Modified / Q000235:genetics; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016622:Silver Staining; D013997:Time Factors; D014026:Nicotiana / Q000201:enzymology*; D014157:Transcription Factors / Q000737:chemistry; D015854:Up-Regulation
D029681:Arabidopsis Proteins; D017931:DNA Primers; D019204:GTP-Binding Proteins; D009004:Monosaccharide Transport Proteins; D050901:Nitrate Reductase; D009565:Nitrate Reductases; D009566:Nitrates; D009841:Oligonucleotides; D012313:RNA; D014157:Transcription Factors; C435922:At1g10760 protein, Arabidopsis