Engineering Mycorrhizal Symbioses to Alter Plant Metabolism and Improve Crop Health

Abstract

Creating sustainable bioeconomies for the 21st century relies on optimizing the use of biological resources to improve agricultural productivity and create new products. Arbuscular mycorrhizae (phylum Glomeromycota) form symbiotic relationships with over 80% of vascular plants. In return for carbon, these fungi improve plant health and tolerance to environmental stress. This symbiosis is over 400 million years old and there are currently over 200 known arbuscular mycorrhizae, with dozens of new species described annually. Metagenomic sequencing of native soil communities, from species-rich meadows to mangroves, suggests biologically diverse habitats support a variety of mycorrhizal species with potential agricultural, medical, and biotechnological applications. This review looks at the effect of mycorrhizae on plant metabolism and how we can harness this symbiosis to improve crop health. I will first describe the mechanisms that underlie this symbiosis and what physiological, metabolic, and environmental factors trigger these plant-fungal relationships. These include mycorrhizal manipulation of host genetic expression, host mitochondrial and plastid proliferation, and increased production of terpenoids and jasmonic acid by the host plant. I will then discuss the effects of mycorrhizae on plant root and foliar secondary metabolism. I subsequently outline how mycorrhizae induce three key benefits in crops: defense against pathogen and herbivore attack, drought resistance, and heavy metal tolerance. I conclude with an overview of current efforts to harness mycorrhizal diversity to improve crop health through customized inoculum. I argue future research should embrace synthetic biology to create mycorrhizal chasses with improved symbiotic abilities and potentially novel functions to improve plant health. As the effects of climate change and anthropogenic disturbance increase, the global diversity of arbuscular mycorrhizal fungi should be monitored and protected to ensure this important agricultural and biotechnological resource for the future.

Dual RNA-seq reveals large-scale non-conserved genotype x genotype specific genetic reprograming and molecular crosstalk in the mycorrhizal symbiosis

“…While significant progress has been made in discovering plant genes that are in involved in the establishment of the symbiosis, identification of important fungal genes involved in these interactions are extremely limited [22-24]. Firstly, this is because stable transformation of AMF has not yet been achieved [25]. Secondly, AMF cannot be cultured without a host.…”

Native Mycorrhizal Fungi in Land Contaminated Cr, Co and Cu

“…Several reports and reviews show that mycorrhizal from areas contaminated with heavy metals has developed tolerance to heavy metal toxicity and adapted well. Mycorrhizal has been proven to evolve tolerance to heavy metals, as stated by Lingua et al (2012) and French (2017), Some strains of mycorrhizal fungi tolerant develop in one or two years. However, to date, the potential interaction mechanism between mycorrhizal fungi and heavy metal, as well as cellular and molecular mechanisms about the tolerance of heavy metals by mycorrhizal fungi, is still poorly understood.…”

Distinct gene expression and secondary metabolite profiles insuppressor of prosystemin-mediated responses2 (spr2)tomato mutants having impaired mycorrhizal colonization

“…Arbuscular mycorrhizal fungi colonization has been found to profoundly alter gene expression in roots of several plants species (Guimil et al, 2005;Fiorilli et al, 2009;Guether et al, 2009;Hogekamp & Küster, 2013;Groten et al, 2015), whereas a number of large-scale gene expression studies have explored the systemic effects that AMF root colonization has in plant aerial tissues (Guimil et al, 2005;Cervantes-Gamez et al, 2016;Adolfsson et al, 2017;Wang et al, 2018a). Changes in root and leaf metabolite levels in response to AMF colonization, have been also reported, particularly affecting amino acid (aa), carbohydrate and organic acid contents (Schweiger et al, 2014;Rivero et al, 2015;Schweiger & Müller, 2015;French, 2017;Bedini et al, 2018;Wang et al, 2018a).…”