Effects of arbuscular mycorrhizal fungi on above‐ground tri‐trophic interactions are contingent upon plant genetic effects of cross type in the perennial herb Ruellia nudiflora

Abstract

Recent work has improved our understanding of the linkages between above‐ and below‐ground interactions mediated by plants. However, relatively few of the studies conducted thus far have focused on multi‐trophic interactions (i.e. beyond two trophic levels) and the influence of plant genetic intraspecific variation on these dynamics has rarely been addressed. We tested the effect of arbuscular mycorrhizal fungi (AMF) on above‐ground tri‐trophic interactions associated with the canopy of the perennial herb Ruellia nudiflora, and further determined whether genetic effects due to cross type (i.e. whether a plant originated from self‐ or cross‐pollination) influenced these interactions. We propagated plants originating from self‐ or cross‐pollination, and within each category inoculated half of the plants with AMF. We subsequently established a common garden where plants were exposed to naturally occurring seed‐eating caterpillars and their parasitoids. We measured plant growth, fruit output, calculated the proportion of attacked fruits by the caterpillar and the proportion of parasitized caterpillars, and also estimated the proportion of “rescued” seeds by parasitoids representing an indirect positive effect of the third trophic level on the plant by reducing caterpillar consumption. Arbuscular mycorrhizal fungi drove 18% and 15% increases in plant growth and fruit output respectively, and drove a 25% reduction in caterpillar fruit attack, but did not influence parasitism or parasitoid seed “rescue.” In contrast, cross type did not influence growth, fruit number, herbivore attack, parasitism or seed rescue. More importantly, however, we found a significant AMF by cross type interaction on caterpillar attack, where AMF significantly reduced fruit attack (by 30%) in progeny from cross‐pollination but did not influence herbivory in progeny from self‐pollination. Synthesis. Results indicate that effects of arbuscular mycorrhizal fungi on above‐ground interactions are contingent upon plant intraspecific variation originating from cross type, which is likely a common source of variation in associated interactions for plants with mixed mating systems. Further studies examining plant‐mediated below‐ and above‐ground interactions should consider the influence of specific sources of plant genetic variation, as well as address the consequences of such dynamics for interactions beyond two trophic levels.

The joint effect of host plant genetic diversity and arbuscular mycorrhizal fungal communities on restoration success

“…Mejia‐Alva et al. (2018) found that inoculation with AM fungi decreased caterpillar fruit attack in a perennial herb, originating from cross‐pollinated parent plants. Ignoring such effects in ecological restoration can lead to a negligible impact of microbial inoculation and may decrease the cost‐efficiency of restoration activities (Koziol et al., 2018).…”

Making partners in the city: impact of urban soil P enrichment on the partnership between an invasive herb and arbuscular mycorrhizal fungi in a tropical city

“…Hence, disentangling the roles of urban abiotic factors on the ecology of biotic interactions is key to understanding causal relationships that drive adaptation to urban environments. For instance, soil nutrient enrichment in urban environments can alter the soil microbiota that play a central role in plant physiology, aboveground interactions, and fitness (Mejia-Alva et al 2018;Irwin et al 2020).…”

“…AM fungi are obligate symbionts, which increase availability of N and P to plants in exchange for carbon (Smith & Smith 2011). They can also confer resistance to various biotic and abiotic stresses, thus increasing plant survival and reproduction (Ramos-Zapata et al 2010;Wu & Zou 2017;Mejia-Alva et al 2018). Nevertheless, this association, measured as the AM colonization rate, can be disrupted by increasing soil P and N concentrations (Salvioli di Fossalunga & Novero 2019), which reduce benefits of the association with AM fungi (Smith & Smith 2011).…”

“…2010; Wu & Zou 2017; Mejia‐Alva et al . 2018). Nevertheless, this association, measured as the AM colonization rate, can be disrupted by increasing soil P and N concentrations (Salvioli di Fossalunga & Novero 2019), which reduce benefits of the association with AM fungi (Smith & Smith 2011).…”

iTRAQ Proteomic Analysis of Continuously Cropped Soybean Root Inoculated With Funneliformis mosseae

“…Arbuscular mycorrhizal fungi (AMF) form specific arbuscular structures and vesicles by infecting the roots of terrestrial vascular plants, thereby enhancing the absorption and transport of carbon, nitrogen, mineral elements and water in plant roots, which promotes plant growth and development, nutritional metabolism, and photosynthesis. AMF are therefore known as biofertilizers (Alva et al, 2017; Luginbuehl et al, 2017), and they have also been associated with resistance to stresses such as salinity and alkalinity, heavy metals, and drought (Tao et al, 2016; Alojz et al, 2017; Shi et al, 2017; Xu et al, 2017), and resistance to diseases including root rot, verticillium wilt and other wilt diseases (Qian et al, 2015; Fauziyah et al, 2017; Sharma and Sharma, 2017; Tripathi et al, 2017). The effects of inoculation with AMF have been widely studied, and the symbiotic relationships between AMF and plants have been analyzed using proteomics.…”