The role of inoculum identity in drought stress mitigation by arbuscular mycorrhizal fungi in soybean

Abstract

It is well known that arbuscular mycorrhizal fungi (AMF) effects on plant growth largely depend on fungus identity. The objective of this study was to test whether three individual AMF isolates and their mixture, mitigate drought stress (DS) differentially in soybean (Glycine max) genotype, predicting that under DS, the mixture of the AMF isolates would provide greater benefits to soybean plants than individual ones. In a greenhouse experiment, a drought-susceptible soybean genotype was inoculated with Septoglomus constrictum, Glomus sp.Glomus aggregatum, known to be among the most abundant in agricultural and natural soils from central Argentina, and their mixture (Mx). Whereas under well watered (WW) conditions individual isolates and Mx treatment were similarly infective, under DS conditions, the Mx treatment showed lower rates of root colonization. Between WW and DS conditions, biomass was decreased in all treatments, although this effect was more marked in non-AM plants. Moreover, AMF strains improved water content and P and N concentration.Under DS, the Mx treatment was unable to exceed the highest contents that were recorded by AMF isolates.However, under WW conditions the Mx treatment showed a higher N content than individual isolates. Under 3 3 both watering conditions, AM-plants reduced oxidative damage evaluated as malondiadehyde and chlorophyll content and keep constant osmotic metabolites such as soluble sugars and proline content, without significant differences between AMF isolates and the Mx treatment. These results show that AMF play an important role in mitigating drought impacts on soybean, but that mixtures of AMF isolates did not perform as well as the best single strain inoculum, excluding complementarity effects and suggesting selection effect of AMF on DS alleviation in soybean.

Responses of Different Panicum miliaceum L. Genotypes to Saline and Water Stress in a Marginal Mediterranean Environment

“…No reduction in leaf chlorophyll content was observed, probably due to the relatively brief exposition to salt stress because of the short growing season. Water stress conditions (25% ETm) exerted highly negative effects on leaf characteristics; in these conditions, AMF inoculation could partially overcome such negative effects, confirming their beneficial role in plant water status under drought stress (Beltrano and Ronco 2008;Grümberg et al 2015) [62,63].…”

Edaphic and host plant factors are linked to the composition of arbuscular mycorrhizal fungal communities in the root zone of endangeredUlmus chenmouiCheng in China

“…In this study, the AMF phylotypes found in the LY‐2 sample site, especially with respect to the most abundant genus, Septoglomus , must have some traits that allow them to adapt to the specific conditions at this site or to survive as highly adapted spores in the soil. Some studies have demonstrated that Septoglomus was found exclusively under extreme conditions of drought and high temperatures (Bonfim et al, ; Symanczik, Chwat, Boller, Wiemken, & Alyahya'Ei, ) and can play an important role in mitigating drought impact on plants (Grümberg, Urcelay, Shroeder, Vargas‐Gil, & Luna, ). Moreover, the difference in the diversity and community composition of AM fungi under the unhealthy trees in LY‐2, particularly the relatively high frequency of Septoglomus (7.53%), compared to sites LY‐1 (0.99%) and LY‐3 (3.67%), which both contained healthy trees, suggested that the host plants in LY‐2 may allocate different (qualitatively and/or quantitatively) carbon resources to their AM fungal partners (Aguilar‐Trigueros, Powell, Anderson, Antonovics, & Rilling, ), such as specific root‐exudate patterns.…”

“…tures (Bonfim et al, 2016;Symanczik, Chwat, Boller, Wiemken, & Alyahya'Ei, 2014) and can play an important role in mitigating drought impact on plants (Grümberg, Urcelay, Shroeder, Vargas-Gil, & Luna, 2015). Moreover, the difference in the diversity and community composition of AM fungi under the unhealthy trees in LY-2, particularly the relatively high frequency of Septoglomus (7.53%), F I G U R E 5 Proportion of total read numbers of operational taxonomic units (OTUs) grouped by arbuscular mycorrhizal fungal (AMF) genus in the root zone of U. chenmoui.…”

Could biological invasion by Cryptostegia madagascariensis alter the composition of the arbuscular mycorrhizal fungal community in semi-arid Brazil?

“…AMF benefit plants by mediating the availability of important plant nutrients (Smith & Read 2008;Hodge & Storer 2014), promote plant growth and offer protection against drought and soil pathogens (Rodríguez-Echeverría et al 2009;Grümberg et al 2015;Ortiz et al 2015). We examined the AMF community from Cryptostegia madagascariensis root zone, and compared it with the AMF community from Copernicia prunifera root zone.…”