symbiosis; evolution; mycorrhizal fungi; genetics; evolutionary genomics; transcriptomics; mycorrhizal symbiosis; fungi,; plants,; genetic exchange; segregation, productivity
(2012), The transcriptome of the arbuscular mycorrhizal fungus Glomus intraradices (DAOM 197198) reveals functional tradeoffs in an obligate symbiont, in NEW PHYTOLOGIST
, 193(3), 755-769.
(2011), Genetic exchange in an arbuscular mycorrhizal fungus results in increased rice growth and altered mycorrhiza-specific gene transcription., in Applied and environmental microbiology
, 77(18), 6510-5.
(2011), Mycorrhizal symbioses: how to be seen as a good fungus., in Current biology : CB
, 21(14), 1216-1221.
(2011), Effect of segregation and genetic exchange on arbuscular mycorrhizal fungi in colonization of roots., in The New phytologist
, 189(3), 652-7.
(2010), Arbuscular mycorrhiza: the challenge to understand the genetics of the fungal partner., in Annual review of genetics
, 44, 271-92.
(2010), 'Designer' mycorrhizas?: Using natural genetic variation in AM fungi to increase plant growth., in The ISME journal
, 4(9), 1081-3.
(2010), Segregation in a mycorrhizal fungus alters rice growth and symbiosis-specific gene transcription., in Current biology : CB
, 20(13), 1216-1221.
(2010), Characterisation of microbial communities colonising the hyphal surfaces of arbuscular mycorrhizal fungi., in The ISME journal
, 4(6), 752-63.
(2010), The role of mycorrhizas in more sustainable oil palm cultivation, in AGRICULTURE ECOSYSTEMS & ENVIRONMENT
, 135(3), 187-193.
Arbuscular mycorrhizal fungi (AMF) are extremely abundant symbionts. They form symbioses with the majority of plant species. Through this symbiosis plants benefit by receiving more phosphorus and also by gaining protection against fungal pathogens. The fungi have also been shown to promote plant diversity and productivity. Because of these benefits there is great interest in using these fungi for improving agricultural productivity and also in many ecological applications such as re-vegetation programs on polluted soils and establishment of diverse plant communities.Little is known about the genetics and about many aspects of the general biology and ecology of AMF. Fully understanding the evolution of these important symbionts and their co-evolution with plants is impossible without a basic knowledge of AMF genetics and their genomes. Studies made by our group over the last few years have shown that AMF exhibit unusual genetic variation, even within single spores. Recently, AMF have been shown to contain genetically different nuclei. Although AMF were thought to be ancient asexuals, genetic exchange has just been demonstrated to occur. Furthermore, a population-based approach indicates that AMF are also recombinant. A consequence of genetic exchange in AMF is that new spores that are genetically different from the parents can be produced. Because the fungi contain a higher diversity of genetically different nuclei, following genetic exchange, there is a strong possibility that further differences among progeny can occur due to segregation of different nuclei during spore formation. We have documented this segregation and have shown that both genetic exchange and segregation can lead to large, significant differences in plant growth. The results are even more surprising because they were observed in rice which is thought to normally respond very poorly, if at all, to colonization by AMF. This project seeks to investigate in detail the consequences of genetic manipulation of the fungus on plant and fungal phenotypes, and on the expression of genes in both partners of the symbiosis. We will achieve this through a combination of genomics and transcriptomics approaches using sequencing of genomic DNA, and cDNA constructed from RNA originating from roots of rice plants colonized with different manipulated genetic lines of the fungus. The project will enable us to assess the extent of genetic differences that occur after genetic exchange or segregation, compared to parental lines and also allow us to determine how this affects gene expression and the phenotype of both partners of the symbiosis. We propose to concentrate on the interaction between G. intraradices and rice because the genomes of both organisms have, or are being, sequenced and because microarrays are available for both species. Furthermore, rice is an extremely important food crop that feeds more people in the world than any other plant. Preliminary experiments also show that, following genetic exchange, the identity of the host plant species can play a role in shaping the phenotype of the fungus and also play a role in altering the genotype of the fungus. We will investigate this further. We also propose to study how stable or heritable the genotypes and phenotypes of AMF are following genetic exchange and segregation. This is important for understanding how genetic variability is maintained in the fungus and important for applying AMF genetic manipulation in commercial inoculum production.The results of our experiments will greatly further our understanding of the role of AMF genetics in this important symbiosis and this information will be invaluable for research on the ecology and evolution of the symbiosis, as well as understanding the molecular basis for the interaction between these important fungi and plants. There is an added value to the project because the genetic manipulation uses natural processes with no genetic transformation. This means that it could be used for improving the efficiency of commercial AMF inoculum production and be used for a more sustainable agriculture. To this end, we have an agreement with two collaborators (a commercial inoculum producer and an agronomist) who will investigate these possibilities.