Root exudates stimulate the uptake and metabolism of organic carbon in germinating spores of Glomus intraradices.
* Root exudates play a key role during the presymbiotic growth phase and have been shown to stimulate hyphal branching and the catabolic metabolism of arbuscular mycorrhizal (AM) fungal spores. * Here, the effect of root exudates on presymbiotic growth, uptake of exogenous carbon and transcript levels for genes putatively involved in the carbon metabolism of germinating spores were determined. * Crude root exudates led to a slight acceleration of spore germination, increased germ tube branching and stimulated uptake and catabolic metabolism of acetate, and to a greater extent of glucose, but had no effect on gene expression. By contrast, partially purified root exudates increased the transcript levels of acyl-CoA dehydrogenase (ss-oxidation of fatty acids to acetyl-CoA), malate synthase (glyoxylate cycle) and glutamine-fructose-6-phosphate aminotransferase (chitin biosynthesis), but did not differ from crude root exudates in their effect on substrate uptake and respiration. The expression of glycogen synthase (glycogen biosynthesis), glucose-6-phosphate dehydrogenase (pentose phosphate pathway) and neutral trehalase (hydrolysis of trehalose) were only marginally or not affected by root exudates. * Root exudates have an effect on both membrane activity and gene expression and the results are discussed in relation to the catabolic and anabolic metabolism of spores during presymbiotic growth.
Bücking
Heike
H
Rutgers, State University of New Jersey, Biology Department, Camden, NJ 08102, USA.
Abubaker
Jehad
J
New Mexico State University, Department Biochemistry and Chemistry, Las Cruces, NM 88001, USA.
Govindarajulu
Manjula
M
New Mexico State University, Department Biochemistry and Chemistry, Las Cruces, NM 88001, USA.
Tala
Marie
M
Rutgers, State University of New Jersey, Biology Department, Camden, NJ 08102, USA.
Pfeffer
Philip E
PE
USDA ARS Eastern Regional Research Center, 600 E Mermaid Lane, Wyndmoor, PA 19038, USA.
Nagahashi
Gerald
G
USDA ARS Eastern Regional Research Center, 600 E Mermaid Lane, Wyndmoor, PA 19038, USA.
Lammers
Peter
P
New Mexico State University, Department Biochemistry and Chemistry, Las Cruces, NM 88001, USA.
Shachar-Hill
Yair
Y
Michigan State University, Department Plant Biology, East Lansing, MI 48824-1312, USA.
D000042:Absorption; D000085:Acetates / Q000378:metabolism; D002244:Carbon / Q000378:metabolism* / Q000493:pharmacokinetics; D019069:Cell Respiration; D015870:Gene Expression / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D018525:Germination; D055137:Glomeromycota / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D038821:Mycorrhizae / Q000502:physiology*; D053147:Plant Exudates / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013559:Symbiosis
D000085:Acetates; D053147:Plant Exudates; D002244:Carbon