Commercial arbuscular mycorrhizal fungal inoculant failed to establish in a vineyard despite priority advantage

Abstract

Background Arbuscular mycorrhizal (AM) fungi associate with most plants and can increase nutrient uptake. As a result, commercial inoculants called “biofertilizers” containing AM fungi have been developed and marketed to increase plant performance. However, successful establishment of these inoculants remains a challenge, and may be negatively impacted by competition with fungi already present (priority effects). Perennial agriculture may be more amenable if inoculants can be successfully established on crops prior to field planting. Methods Here, we inoculate grapevine (Vitis vinifera) with a commercial inoculant in three treatments designed to manipulate the strength and direction of priority effects and quantified the abundance of the fungal strain before and after introduction using droplet digital PCR (ddPCR). Results We found that the introduced strain did not establish in any treatment, even with priority advantage, and inoculated vines did not differ in performance from non-inoculated vines. Fungal abundance was not greater than in pre-inoculation soil samples during any of the five years sampled and may have been impaired by high available phosphorus levels in the soil. This study highlights the need to understand and evaluate how the management of the agricultural system will affect establishment before introduction of “biofertilizers”, which is often unpredictable.

Homo- and Dikaryons of the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis Differ in Life History Strategy

“…The most commonly used strain for inoculants ( R. irregularis DAOM197198—homokaryon) grows fast in carrot ROC and produces large quantities of spores ( Douds, 2002 ; Rosikiewicz et al, 2017 ). However, there were cases in which it reduced host nutritional benefits ( Kokkoris and Hart, 2019a , b ; Kokkoris et al, 2019a ) and failed to establish in large-scale inoculation trials ( Farmer et al, 2007 ; Kokkoris et al, 2019b ; Thomsen et al, 2021 ). In this study, DAOM197198 grew well with carrot as host plant and produced the most spores among all homokaryons, but surprisingly ranked last in terms of growth and spore production with the other two host plants, indicating host preference.…”

Isolation and identification of indigenous Arbuscular Mycorrhizal Fungi (AMF) of forest clove rhizosphere from Maluku, Indonesia

“…The type of spore is only germinated to hyphae but then dies because it does not infect the host plant in trapping culture. Mycorrhizal hyphae could only survive for 20-30 days without association with the host plant (Sukmawati et al 2021;Thomsen et al 2021). The infectivity and effectiveness of mycorrhizae are primarily determined by biotic factors such as the type of mycorrhizae, the host plant, microbial interactions, the type of soil of the host plant, and the composition between fungi and abiotic factors such as environmental factors, especially soil (Piliarová et al 2019;Lara-Capistran et al 2021;Meng et al 2021).…”

“…Chemical fertilizers can increase the productivity of cloves, but their use in the long term can harm the environment and the quality of crop yields. Biological agents such as mycorrhizae can be applied to increase productivity and quality of clove in the long term (Putri et al 2016; Thomsen et al 2021). Arbuscular mycorrhizal fungi (AMF) are symbiotic with plants (Wang et al 2017;Meng et al 2021).…”

“…It is possible to find mycorrhizae with different types and densities in two different distribution areas. According to Asmelash et al (2021) and Thomsen et al (2021), the presence of AMF is strongly influenced by the type of host plant, spore type, and environmental factors such as soil.…”

Do Bioinoculants Affect Resident Microbial Communities? A Meta-Analysis

“…While questions remain about the use of these products (Kokkoris et al, 2019a;Thomsen et al, 2021), their effects in natural ecosystems including their invasiveness and interactions with the indigenous soil microbes have received little attention (Trabelsi and Mhamdi, 2013;Ambrosini et al, 2016;Hart et al, 2017). Many studies include information about soil microbial communities (SMC) post-inoculation, but there is little consensus on the effect of inoculants on SMC diversity.…”