Soil inoculation with symbiotic microorganisms promotes plant growth and nutrient transporter genes expression in durum wheat

Abstract

In a field experiment conducted in a Mediterranean area of inner Sicily, durum wheat was inoculated with plant growth-promoting rhizobacteria (PGPR), with arbuscular mycorrhizal fungi (AMF), or with both to evaluate their effects on nutrient uptake, plant growth, and the expression of key transporter genes involved in nitrogen (N) and phosphorus (P) uptake. These biotic associations were studied under either low N availability (unfertilized plots) and supplying the soil with an easily mineralizable organic fertilizer. Regardless of N fertilization, at the tillering stage, inoculation with AMF alone or in combination with PGPR increased the aboveground biomass yield compared to the uninoculated control. Inoculation with PGPR enhanced the aboveground biomass yield compared to the control, but only when N fertilizer was added. At the heading stage, inoculation with all microorganisms increased the aboveground biomass and N. Inoculation with PGPR and AMF+PGPR resulted in significantly higher aboveground P compared to the control and inoculation with AMF only when organic N was applied. The role of microbe inoculation in N uptake was elucidated by the expression of nitrate transporter genes. NRT1.1, NRT2, and NAR2.2 were significantly upregulated by inoculation with AMF and AMF+PGPR in the absence of organic N. A significant down-regulation of the same genes was observed when organic N was added. The ammonium (NH4+) transporter genes AMT1.2 showed an expression pattern similar to that of the NO3- transporters. Finally, in the absence of organic N, the transcript abundance of P transporters Pht1 and PT2-1 was increased by inoculation with AMF+PGPR, and inoculation with AMF upregulated Pht2 compared to the uninoculated control. These results indicate the soil inoculation with AMF and PGPR (alone or in combination) as a valuable option for farmers to improve yield, nutrient uptake, and the sustainability of the agro-ecosystem.

Growth and Nutrient Uptake of Orchardgrass (Dactylis glomerata L.) and Meadow Fescue (Festuca pratensis Huds.) as Affected by Rhizobacteria

“…Increases in growth and yield of crops in response to inoculation with PGPR have been repeatedly reported (Baris et al, 2014;Dinesh et al, 2015;Imran et al, 2015;Saia et al, 2015). PGPR exert positive effect on plant growth by direct mechanisms, such as biological N2 fixation, phosphate solubilisation and production of growth regulators (phytohormones), or by indirect mechanisms, such as prevention of the deleterious effects of plant pathogens, production of inhibitory substances (siderophore, antibiotics), or increase of natural resistance of the host (Glick, 1995).…”

Spore Density of Arbuscular Mycorrhizal Fungi is Fostered by Six Years of a No-Till System and is Correlated with Environmental Parameters in a Silty Loam Soil

“…In addition, among AMF species, there are different levels of tolerance to the disruption of hyphae resulting from tillage [11]. Inoculation with AMF spores has recently been shown to increase plant growth [12] and the expression of nitrate and phosphate transporter genes in wheat roots [13]. Moreover, inoculation can be used to offset tillage effects on the number of indigenous spores.…”

Arbuscular mycorrhizal fungi altered the hypericin, pseudohypericin, and hyperforin content in flowers of Hypericum perforatum grown under contrasting P availability in a highly organic substrate

“…This occurs mostly because of the ability of the AM fungi to take up nutrients with low mobility or low concentration within the soil solution and under various stress conditions (Smith and Read 2008). The advantages of AM symbiosis to host plants have been demonstrated extensively in terms of enhancement of plant biomass and nutrient uptake, especially in cereals and legumes (Kaschuk et al 2010;Saia et al 2015a;Pellegrino et al 2015;Bona et al 2016a). In medicinal and aromatic plants (MAPs), most of the information about the effects of AM fungi has been derived from investigations about the family Lamiaceae (Khaosaad et al 2006;Copetta et al 2006;Zeng et al 2013;López-García et al 2014;Bona et al 2016b; Silvia Lazzara and Marcello Militello equally contributed to this work.…”