Analysis of the molecular and biochemical mechanisms involved in the symbiotic relationship between Arbuscular mycorrhiza fungi and Manihot esculenta Crantz

Abstract

IntroductionPlants and arbuscular mycorrhizal fungi (AMF) mutualistic interactions are essential for sustainable agriculture production. Although it is shown that AMF inoculation improves cassava physiological performances and yield traits, the molecular mechanisms involved in AM symbiosis remain largely unknown. Herein, we integrated metabolomics and transcriptomics analyses of symbiotic (Ri) and asymbiotic (CK) cassava roots and explored AM-induced biochemical and transcriptional changes.ResultsThree weeks (3w) after AMF inoculations, proliferating fungal hyphae were observable, and plant height and root length were significantly increased. In total, we identified 1,016 metabolites, of which 25 were differentially accumulated (DAMs) at 3w. The most highly induced metabolites were 5-aminolevulinic acid, L-glutamic acid, and lysoPC 18:2. Transcriptome analysis identified 693 and 6,481 differentially expressed genes (DEGs) in the comparison between CK (3w) against Ri at 3w and 6w, respectively. Functional enrichment analyses of DAMs and DEGs unveiled transport, amino acids and sugar metabolisms, biosynthesis of secondary metabolites, plant hormone signal transduction, phenylpropanoid biosynthesis, and plant-pathogen interactions as the most differentially regulated pathways. Potential candidate genes, including nitrogen and phosphate transporters, transcription factors, phytohormone, sugar metabolism-related, and SYM (symbiosis) signaling pathway-related, were identified for future functional studies.DiscussionOur results provide molecular insights into AM symbiosis and valuable resources for improving cassava production.

Effect of Arbuscular Mycorrhizal Fungi on Nitrogen and Phosphorus Uptake Efficiency and Crop Productivity of Two-Rowed Barley under Different Crop Production Systems

“…Additionally, AM symbiosis enhances plant growth, productivity, and resistance to biotic and abiotic stresses [23][24][25]. In general, the development of the AM symbiosis can be divided into four phases [26]. In the first phase, the two symbionts cross-talk using diffusible signal molecules; in particular, fungi typically exude lipo-chitooligosaccharides, whereas plants produce strigolactones.…”

“…The third phase involves the penetration and proliferation of fungal hyphae into the apoplast of the cortex, altering their typical appearance. In the last phase, arbuscules are formed by fungal hyphae penetrating and multiplying in the inner cortex, resulting in colonization of the surface [26]. Both symbionts exchange nutrients through arbuscules, and the formation of these arbuscules causes de novo synthesis of the peri-arbuscular membrane surrounding the cytoplasm [27].…”

“…Both symbionts exchange nutrients through arbuscules, and the formation of these arbuscules causes de novo synthesis of the peri-arbuscular membrane surrounding the cytoplasm [27]. An interaction between translocation factors and phytohormones (auxin, gibberellin, abscisic acid, strigolactones and ethylene) regulates the symbiosis signaling pathway and symbiont interactions [26,28]. Through the formation of arbuscules, the expression patterns of many genes in AM roots are altered, which results in a variation in primary and secondary metabolites as well as improved production [29].…”