Laser microdissection and its application to analyze gene expression in arbuscular mycorrhizal symbiosis

Abstract

Phosphorus is essential for plant growth, and in many soils phosphorus availability limits crop production. Most plants in natural ecosystems obtain phosphorus via a symbiotic partnership with arbuscular mycorrhizal (AM) fungi. While the significance of these associations is apparent, their molecular basis is poorly understood. Consequently, the potential to harness the mycorrhizal symbiosis to improve phosphorus nutrition in agriculture is not realized. Transcript profiling has recently been used to investigate gene expression changes that accompany development of the AM symbiosis. While these approaches have enabled the identification of AM-symbiosis-associated genes, they have generally involved the use of RNA from whole mycorrhizal roots. Laser microdissection techniques allow the dissection and capture of individual cells from a tissue. RNA can then be isolated from these samples and cell-type specific gene expression information can be obtained. This technology has been applied to obtain cells from plants and more recently to study plant-microbe interactions. The latter techniques, particularly those developed for root-microbe interactions, are of relevance to plant-parasitic weed research. Here, laser microdissection, its use in plant biology and in particular plant-microbe interactions are discussed. An overview of the AM symbiosis is then provided, with a focus on recent advances in understanding development of the arbuscule-cortical cell interface. Finally, the recent applications of laser microdissection for analyses of AM symbiosis are discussed.

Combining laser microdissection and RNA-seq to chart the transcriptional landscape of fungal development

“…Our study demonstrates that young fruiting bodies of S. macrospora can be isolated using LM, and RNA extracted from these samples in sufficient amounts for RNA-seq after two rounds of linear amplification. The amplification process largely conserves expression ratios, as demonstrated by comparing the expression of selected genes prior to amplification with the RNA-seq results, which is consistent with results from other organisms where linear RNA amplification was used to prepare samples for microarray hybridization [19,20]. We also found some overlap with prior microarray experiments in which we compared gene expression in vegetative and sexual mycelia; however, in these experiments we used mycelia grown in defined medium [9], whereas for RNA-seq analysis, RNA from mycelia grown in defined medium and cornmeal medium were pooled.…”

Flowers and mycorrhizal roots – closer than we think?

“…An important aspect of such comparative work should involve the precise transcriptomic analysis of the different cell types in anthers and mycorrhizal roots in an AM-competent species such as M. truncatula or rice. Gene expression data with high spatial and temporal resolution could be obtained using techniques such as cell sorting [64,65] or laser-assisted micro-dissection in mycorrhizal roots [66,67] and in pollen development [68,69]. Using such a systematic comparative approach, and exchanging information and ideas from the two research domains, could help to explain common and differential elements in these seemingly very different realms of plant biology.…”

Revealing Natural Relationships among Arbuscular Mycorrhizal Fungi: Culture Line BEG47 Represents Diversispora epigaea, Not Glomus versiforme

“…[15]–[17]). The type material of both, G. epigaeum and G. versiforme (synonym Endogone versiformis ) and the synonymisation [18] of BEG47 with G. versiforme were re-examined.…”