Arbuscular Mycorrhizal Symbiosis Primes Tolerance to Cucumber Mosaic Virus in Tomato

Abstract

Tomato plants can establish symbiotic interactions with arbuscular mycorrhizal fungi (AMF) able to promote plant nutrition and prime systemic plant defenses against pathogens attack; the mechanism involved is known as mycorrhiza-induced resistance (MIR). However, studies on the effect of AMF on viral infection, still limited and not conclusive, indicate that AMF colonization may have a detrimental effect on plant defenses against viruses, so that the term “mycorrhiza-induced susceptibility” (MIS) has been proposed for these cases. To expand the case studies to a not yet tested viral family, that is, Bromoviridae, we investigated the effect of the colonization by the AMF Funneliformis mosseae on cucumber mosaic virus (CMV) infection in tomato by phenotypic, physiological, biochemical, and transcriptional analyses. Our results showed that the establishment of a functional AM symbiosis is able to limit symptoms development. Physiological and transcriptomic data highlighted that AMF mitigates the drastic downregulation of photosynthesis-related genes and the reduction of photosynthetic CO2 assimilation rate caused by CMV infection. In parallel, an increase of salicylic acid level and a modulation of reactive oxygen species (ROS)-related genes, toward a limitation of ROS accumulation, was specifically observed in CMV-infected mycorrhizal plants. Overall, our data indicate that the AM symbiosis influences the development of CMV infection in tomato plants and exerts a priming effect able to enhance tolerance to viral infection.

Mycorrhizal symbiosis primes the accumulation of antiherbivore compounds and enhances herbivore mortality in tomato

“…In return, the AMF assist the host plant in the acquisition of water and mineral nutrients, becoming extremely important for the uptake of inorganic phosphate, nitrogen and various micronutrients (Smith and Smith, 2011 ; Hodge and Storer, 2015 ; Ezawa and Saito, 2018 ). In addition, AM symbiosis also result in an enhanced ability of the host plant to overcome adverse conditions, including abiotic and biotic stress factors ( Sánchez-Bel et al , 2016 ; He et al , 2017 ; Rivero et al , 2018 , Fracasso et al , 2020 ; Miozzi et al , 2020 ; Sanmartín et al , 2020a; b ).…”

Attenuation of Zucchini mosaic virus disease in cucumber plants by mycorrhizal symbiosis

“…Similarly, Khoshkhatti et al ( 2020 ) found that Rhizoglomus irregularis inoculation of tomato plants significantly decreased the Tomato bushy stunt virus (TBSV) symptoms of young plant leaves as compared to non-inoculated ones at 20 dpi. Also, Miozzi et al ( 2020 ) investigated the effect of F. mosseae colonization on tomato infection with cucumber mosaic virus (CMV) at 14 dpi. They demonstrated that infected plants had much more severe viral symptoms and had a threefold higher average DS than AM plants.…”

Microbiota do solo na tolerância de doenças em plantas: Uma revisão

“…Estudos realizados por Spagnoletti et al (2020), demonstram que a severidade da doença da podridão radicular do carvão na soja, causada pelo fungo Macrophomina phaseolina, foi reduzida nas plantas em que houve inoculação com fungos micorrizicos, Rhizophagus intraradices além disso, aumentou a biomassa dessas plantas comparadas as plantas que não apresentavam simbiose. Miozzi et al (2020), observaram o efeito da colonização de FMA da espécie Funneliformis mosseae na infecção pelo vírus do mosaico do pepino (CMV) no tomate, mostrando que o estabelecimento de uma simbiose funcional é capaz de limitar o desenvolvimento dos sintomas, mitiga a redução de genes relacionados a fotossíntese, também acarreta num aumento de ácido salicílico e uma modulação de genes que limitam o acúmulo de espécies reativas de oxigênio, denominando de efeito priming. Song et al (2015), relataram tolerância a Alternaria solani e Fusarium oxysporum em associações micorrízicas na cultura do tomateiro.…”