Symbiosis-regulated expression of an acetyl-CoA acetyltransferase gene in the ectomycorrhizal fungus Laccaria bicolor
Canadian Journal of Botany. 84: 1405-1416.
The ectomycorrhiza is a symbiotic organ generated from the intricate association of fungal hyphae and plant root. The establishment of the ectomycorrhiza is a coordinated process of cross-talk between plant and fungus, followed by metabolic, developmental, and structural changes in the fungus, resulting in its growth toward the root. The initial stages of the symbiotic association are significant, since the direction of the association is determined by the gene expression level shifts that occur at this time. We have isolated a Laccaria bicolor (Maire) Orton cDNA clone corresponding to acetyl-CoA acetyltransferase (Lb-AAT), which is expressed during interaction with red pine roots and is symbiosis regulated. Acetyl-CoA acetyltransferase (EC 126.96.36.199) is an enzyme of the β-oxidation pathway that degrades long-chain fatty acids to acetyl-CoA. Expression of Lb-AAT is regulated by plant presence, by glucose, and by the presence of acetate or oleate in the medium. It is proposed that the role of Lb-AAT in the symbiosis is generation of two carbon compounds from stored lipids and generation of acetoacetyl-CoA in early interaction facilitating net growth from existing cell material. These results coupled with recent microarray analysis that revealed coordinated expression of malate synthase and other lipid metabolism genes along with Lb-AAT, suggest that this role for Lb-AAT could be an important part of preinfection process in ectomycorrhizal symbiosis and in the transfer and utilization of the carbon in the fungus.
Keywordsacetoacetyl-CoA, acetyl-CoA acetyltransferase, b-oxidation, ectomycorrhizae, Laccaria bicolor, Pinus resinosa, symbiosis
Hiremath, Shiv T.; Balasubramanian, Sujata; Zheng, Jun; Podila, Gopi K. 2012. Symbiosis-regulated expression of an acetyl-CoA acetyltransferase gene in the ectomycorrhizal fungus Laccaria bicolor. Canadian Journal of Botany. 84: 1405-1416. https://doi.org/10.1139/B06-104.