Genomic and transcriptomic studies of several species of arbuscular mycorrhizal fungi

Abstract:

Arbuscular mycorrhizal fungi (AMF) are widely distributed in nature and can form mycorrhizal symbiosis with the roots of most vascular plants. They play important ecological roles in the regulation of plant community, and are deeply involved in the global carbon, nitrogen, and phosphorus cycling. They are also the most promising microbial groups in the fields of agriculture, forestry and environment. However, so far the information of their genomic and transcriptomic characters was limited, partially due to the technique limitations in their cultivation. In the past decade, researches on AMF genome and transcriptome have achieved a rapid development under the impetus of high-throughput sequencing. These studies have greatly improved our understanding of AMF in heredity, development, metabolic physiology and symbiosis mechanisms. Here we reviewed the research progresses in the available genomic and transcriptomic information of AMF based on published literature. We found that genomes of available AMF species commonly have large sizes, high transposon abundances, high GC contents, rich in functionally-unknown and species-specific genes, and are lack of some symbiosis-related genes. We also summarized the transcriptomic characteristics of AMF in different symbiotic structures, at different symbiosis stages and with different host plants. The results showed that the transcriptomic sizes generally varied among different AMF species. Also, in different symbiotic structures or at different symbiotic stages, diverse transcriptomic characteristics were found, especially for the expression profiles of genes related to nutrient exchange and signal transduction. In contrast, the transcripts of the same AMF in symbiosis with different host plants were relatively conserved. Finally, we proposed the research directions that need to be focused on in this field, including the innovation of AMF asymbiotic culture technology, the analysis of AMF gene functions, the study of non-model AMF groups and the study of AMF proteome.

Key words:arbuscular mycorrhizal fungi (AMF);Glomeromycota;genomics;transcriptomics;symbiosis