Co-ordinated Changes in the Accumulation of Metal Ions in Maize (Zea mays ssp. mays L.) in Response to Inoculation with the Arbuscular Mycorrhizal Fungus Funneliformis mosseae

Abstract

Arbuscular mycorrhizal symbiosis is an ancient interaction between plants and fungi of the phylum Glomeromycota. In exchange for photosynthetically fixed carbon, the fungus provides the plant host with greater access to soil nutrients via an extensive network of root-external hyphae. Here, to determine the impact of the symbiosis on the host ionome, the concentration of 19 elements was determined in the roots and leaves of a panel of 30 maize varieties, grown under phosphorus-limiting conditions, with or without inoculation with the fungus Funneliformis mosseae. Although the most recognized benefit of the symbiosis to the host plant is greater access to soil phosphorus, the concentration of a number of other elements responded significantly to inoculation across the panel as a whole. In addition, variety-specific effects indicated the importance of plant genotype to the response. Clusters of elements were identified that varied in a co-ordinated manner across genotypes, and that were maintained between non-inoculated and inoculated plants.

Partner communication and role of nutrients in the arbuscular mycorrhizal symbiosis

“…Moreover, an ionomics screen for 19 mineral ions in shoots and roots using the same cohort of 30 maize lines, allowed the identification of clusters of ions, which changed in response to AMF and to maize genotype in a coordinated manner (Ramírez‐Flores et al ., ). It will be interesting to understand how the coordinated uptake of or protection from certain ions occurs and whether these correlations also can be found in a field setting.…”

Inoculation with the mycorrhizal fungus Rhizophagus irregularis modulates the relationship between root growth and nutrient content in maize (Zea mays ssp. mays L.)

“…The third youngest leaf (variously, leaf 5 or 6 for different individuals) was collected for ionomic analysis using inductively coupled plasma mass spectrometry (ICP‐MS) as described previously (Ramírez‐Flores et al, ; Ziegler et al, ). Briefly, weighed tissue samples were digested in 2.5 ml of concentrated nitric acid (AR Select Grade, VWR) with an added internal standard (20 p.p.b.…”

“…The clearest benefit to the plant is enhanced P uptake (Chiu & Paszkowski, ), although AM fungi have been reported to promote uptake of other elements, including N, Fe, S, and Zn (Allen & Shachar‐Hill, ; González‐Guerrero et al, ; Govindarajulu et al, ; Liu, Hamel, Hamilton, Ma, & Smith, ; López‐Pedrosa & González‐Guerrero, ). In practice, complex interactions between nutrients influence the outcome of the symbiosis with respect to any given element (Gerlach et al, ; Liu et al, ; Ramírez‐Flores et al, ). Although AM symbioses are widespread in both natural ecosystems and cultivated fields, the plant host maintains a degree of control over establishment and the extent of colonization, rejecting the fungus under high nutrient conditions (Nouri, Breuillin‐Sessoms, Feller, & Reinhardt, ).…”

“…The impact of AM symbiosis on nutrient uptake can be quantified by comparing the concentration or content of a given element in the aerial portion of mycorrhizal (M) and non‐colonized (NC) plants (Gerlach et al, ; Ramírez‐Flores et al, ). Such a comparison, however, does not distinguish direct hyphal nutrient delivery from the secondary consequences of fungus‐induced modification of root architecture or the effects of greater root growth resulting from a general increase in plant vigor.…”

The Impact of Genetic Changes during Crop Domestication

“…There is growing evidence that microbial partnerships can alter plant nutrient status beyond simply levels of nitrogen or phosphorus (e.g., [130,131]). In recent years, our capacity to characterize the microbiome of plants has increased immensely (e.g., [125,132]) with enormous potential for agriculture and plant biology.…”