Construction and applications of a mycorrhizal arbuscular specific cDNA library

Abstract

To exploit the potential benefits of mycorrhizas, we need to investigate the processes that occur in these symbiotic interactions, particularly in the arbuscular compartment where nutrients are exchanged between the plant and the fungus. Progress in this area is restricted due to the intricacy and complexity of this plant-fungus interface and many techniques that have been employed successfully in other plants and animal systems cannot be used. An effective approach to study processes in arbuscules is to examine transcript composition and dynamics. We applied laser capture microdissection (LCM) to isolate approximately 3000 arbuscules from Glomus intraradices colonised Medicago truncatula roots. Total RNA was extracted from microdissected arbuscules and subjected to T7 RNA polymerase-based linear amplification. Amplified RNA was then used for construction of a cDNA library. The presence and level of enrichment of mycorrhiza-specific transcripts was determined by quantitative Real-time and conventional PCR. To improve enrichment a cDNA library subtraction was performed. Complementation of yeast mutants deficient in the uptake of potassium, phosphate, sulphate, amino acids, ammonium and of a Mn²⁺ sensitive strain, demonstrates the functionality of our cDNA library.