The Arbuscular Mycorrhiza Rhizophagus intraradices Reduces the Negative Effects of Arsenic on Soybean Plants

Abstract

Arsenic (As) in soils causes several detrimental effects, including death. Arsenic toxicity in soybean plants (Glycine max L.) has been little studied. Arbuscular mycorrhiza (AM) increase the tolerance of host plants to abiotic stress, like As. We investigated the effects of AM fungi on soybean grown in As-contaminated soils. A pot experiment was carried out in a glasshouse, at random with five replications. We applied three levels of As (0, 25, and 50 mg As kg −1 ), inoculated and non-inoculated with the AM fungus Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) C. Walker & A. Schüßler. Plant parameters and mycorrhizal colonization were measured. Arsenic in the substrate, roots, and leaves was quantified. Arsenic negatively affected the AM percentage of spore germination and hyphal length. As also affected soybean plants negatively: an extreme treatment caused a reduction of more than 77.47% in aerial biomass, 68.19% in plant height, 78.35% in number of leaves, and 44.96% reduction in root length, and delayed the phenological evolution. Mycorrhizal inoculation improved all of these parameters, and decreased plant As accumulation (from 7.8 mg As kg ). AM inoculation showed potential to reduce As toxicity in contaminated areas. The AM fungi decreased As concentration in plants following different ways: dilution effect, less As intake by roots, and improving soybean tolerance to As.

Rhizoglomus intraradices Improves Plant Growth, Root Morphology and Phytohormone Balance of Robinia pseudoacacia in Arsenic-Contaminated Soils

“…The R. intraradices colonization rate was inhibited by the increase of As concentration in soils. This result was consistent with previous studies on other host species, such as Cajanus cajan, Pisum sativum, and Glycine max L. (Garg et al, 2015;Li et al, 2016;Spagnoletti and Lavado, 2015), but it was contrary to the conclusions of Leung et al (2006). As stress in soils has negative effects on the AM colonization rate due to worsening of the pre-symbiotic conditions of mycorrhizal colonization with As toxicity (Spagnoletti et al, 2016).…”

“…In this study, the shoot and root dry weights in R. intraradices-inoculated R. pseudoacacia seedlings were higher than those in the noninoculated seedlings. R. intraradices inoculation was also found to increase the growth and yield in G. max, Oryza sativa, and Triticum aestivum in As-contaminated soils (Spagnoletti and Lavado, 2015;Li et al, 2016). As is an element of the phosphate analog and has the same transport pathway as phosphate across the plasma membrane of root cells (Chen et al, 2007).…”

“…Exposure to excess As concentrations in soils generally disturbs a series of physiological, biochemical, and morphological processes in plants (Spagnoletti et al, 2016;Sharma et al, 2017). The physiological reactions to As toxicity in plants include inhibited seed germination, reduced growth and yield, decreased chlorophyll content and photosynthesis rate, senescence, and even death, which ultimately lead to vegetation degradation in high As-contaminated areas (Srivastava et al, 2009;Spagnoletti and Lavado, 2015;Spagnoletti et al, 2017). Hence, some remedial measures need to be taken to prevent even further environmental degradation.…”

Endophytic Fungi Piriformospora indica Mediated Protection of Host from Arsenic Toxicity

“…AMF improves nutritional status, impart resistance to soil borne pathogens and tolerance to salt, drought, and heavy metals (Kumar et al, 2009, 2011; Orlowska et al, 2012; Jogawat et al, 2013; Spagnoletti and Lavado, 2015). Previous works have demonstrated the benefits of P. indica over AMF and its application (Varma et al, 1999; Kumar et al, 2009; Yadav et al, 2010; Jogawat et al, 2013).…”

Water management, rice varieties and mycorrhizal inoculation influence arsenic concentration and speciation in rice grains

“…It has been well documented that AMF may play an important role in protecting host plants against As contamination Liu et al 2005). AMF essentially improve plant phosphorus (P) nutrition and growth, which could result in a higher P/As ratio and a dilution effect on As in mycorrhizal plants (Ultra et al 2007;Xia et al 2007;Dong et al 2008;Caporale et al 2014;Spagnoletti and Lavado 2015). Smith et al (2010), Christophersen et al (2012), and He and Lilleskov (2014) compared the root and mycorrhizal Pi/arsenate (As(V)) uptake pathways and confirmed the important role of AMF in plant resistance to As contamination.…”