Arbuscular mycorrhizal fungi: AMF and their interactions with turfgrass species

Mon, 06/08/2020 - 09:00

By Florence Sessoms

In the first part of this series, I described what arbuscular mycorrhizal fungi (AMF) are and how they can benefit plants. In this post, I will discuss how AMF might benefit turfgrasses. Cool-season and warm-season grasses are both able to be infected with mycorrhizal fungi. A quick literature review showed that several benefits of AMF were observed with turfgrasses such as improved biomass, nutrient content, decrease in weed incidence and disease severity (Table 1).

Table 1. List of turfgrasses species infected with mycorrhizal species and some of the benefits observed.
Fungi	Turfgrass	Colonization	Benefits	Paper/Thesis/Report
AMF present in soil	Kentucky bluegrass, Chewings fescue, hard fescue, perennial ryegrass, creeping bentgrass	yes	Increased biomass of perennial ryegrass in greenhouse experiment	Frank, 1984 (Masters thesis at Cornell University, NY, USA)
AMF present in soil	creeping bentgrass, velvet bentgrass, annual bluegrass	yes		Koske et al, 1997
AMF present in soil	creeping bentgrass, annual bluegrass	yes	Some control of annual bluegrass in greens	Gange et al, 1999
Glomus mosseae, G. aggregatum, G. intraradices	Kentucky bluegrass, creeping bentgrass	yes		Podeszfinski et al, 2002
G. fasciculatum, G. mossae	creeping bentgrass, annual bluegrass	yes	Decrease of pink snow mold incidence in greens	Gange and Case, 2002
G. intraradices, G. etunicatum	Kentucky bluegrass, red fescue, perennial ryegrass	yes	Faster establishment with G. intraradices	Pelletier and Dionne, 2004
AMF present in soil and G. intraradices	St. Augstinegrass	yes	No G. intraradices effect on brown patch and take-all roots diseases	Elmore, 2006 (PhD thesis at University of Florida)
G. mosseae	perennial ryegrass	yes	No increase of plant biomass and P nutrition	Chen et al, 2006
G. intraradices	bermudagrass	yes	Improved biomass and regrowth	Wu et al, 2011
G. intraradices, G. etunicatum, G. deserticola	Kentucky bluegrass, tall fescue	yes	Higher biomass and P content	Ehlindi et al, 2018
G. intraradices, G. mossae	Kentucky bluegrass, perennial ryegrass	yes	Improved biomass and mineral nutrition and better tolerance to water stress	Aalipour et al, 2020

Evaluating the effect of AMF on turfgrasses can be extremely complex because these species:

are grown in a multitude of soil environments presenting various chemical and physical properties. The type of soil is going to affect the growth and development of the AMF.
are perennials. Cool season grasses have two active growing seasons in fall and spring. Their ability to survive (slower growth, dormancy or resistance) summer is different species to species. Their growing season during spring-summer and fall is going to affect their relationship with mycorrhizal fungi and could result in variation of the benefits.
are affected by very different diseases throughout the spring, summer and fall seasons. AMF establish better at cool temperatures therefore the potential benefits of AMF against disease can vary in function of the seasonality of the pathogen.
have numerous management practices. Turfgrasses are grown for numerous purposes and can be subjected to very different herbicides, fertility, and mowing practices, all of which can potentially affect the functioning of the interaction.

What are we doing at the University of Minnesota?

turfgrass research plots within a rainout shelter — Figure 1. Several 2-species mixtures are established in one location of the rain-out shelter. There are 6 plots for each mixture. During the spring growing season, 3 plots are inoculated with a consumer-available inoculum and 3 plots are not treated. A potential drought experiment will occur in August and September 2020.

More research is needed to better understand the numerous effects of AMF colonization in turfgrass species. At the University of Minnesota our research with AMF is centered on three projects:

Testing the effect of various AMF fungi on perennial ryegrass and Kentucky bluegrass. The goal of this project is to determine which AMF fungi present the best colonization and improved biomass with one cultivar of each species. A primary experiment has revealed that Glomus etunicatum seems to be beneficial for perennial ryegrass. Most of the fungi tested with Kentucky bluegrass seemed to decrease tiller number of this cultivar. More research using various cultivars with additional fertility treatments is needed.
Testing the effect of an AMF inoculum on the performance of species mixtures (perennial ryegrass, hard fescue, Kentucky bluegrass) during several periods of prolonged drought and recovery from drought. The objective of this project is to determine if AMF inoculation improves drought tolerance, thereby helping to stabilize species composition during several periods of drought. This experiment was dormant seeded in fall 2019 and plots are currently establishing in our rain-out shelter (Figure 1).
Testing the effect of inoculation treatment on different putting green surfaces, including both a USGA-specification green, a native green, each planted to either fine fescue or creeping bentgrass (Figure 2).

a series of four images of turfgrass research plots taken from above — Figure 2. Drone pictures of the different greens tested in this study. The orange dots indicates the mycorrhizal treatment. The blue arrows indicate the decrease of turf quality between the different types of soil and between the different species used.

Questions? If you have any question regarding these projects, please contact me at [email protected].

References

Aalipour et al, (2019). Morpho-physiological and biochemical response of two turfgrass species to arbuscular mycorrhizal fungi and humic acid under water stress conditions. Journal of Soil Science and Plant Nutrition, 20: 566-576.

Chen et al, (2006). Effects of the arbsucular mycorrhizal fungus Glomus mosseae on growth and metal uptake by four plant species in copper mine tailings. Environmental Pollution, 147: 374-380.

Ehlindi et al, (2018). Effects of arbuscular mycorrhizal fungi in the growth of two turfgrasses grown under greenhouse conditions. Soil Science and Plant Nutrition, 64 (2): 238-244.

Elmore (2006). Population and identification of mycorrhizal fungi in St. Augustinegrass in Florida and their effect on soilborn pathogens. PhD thesis dissertation at University of Florida.

Frank (1984). A Study of vesicular arbuscular mycorrhizal (VAM) fungi on cool-season turfgrass. Masters thesis at Cornell University, NY, USA.

Gange et al, (1999). Can arbuscular mycorrhizal fungi be used to control undesirable grass Poa annua on golf courses. Journal of Applied Ecology, 36: 909-919.

Gange and Case (2002). Incidence of microdochium patch disease in golf putting greens and a relationship with arbuscular mycorrhizal fungi. Grass and Forage Science, 58: 58-62.

Koske et al, (1996). Mycorrhizal fungi associated with three species of turfgrass. Canadian Journal of Botany, 75: 320-332.

Pelletier et Dionne (2004). Inoculation rate of arbuscular mycorrhizal fungi Glomus intraradices and Glomus etunicatum affects establishment of landscape turf with no irrigation and or fertilizer inputs. Crop Science, 44:335-338.

Podeszfinski et al, (2002). In situ turfgrass establishment : I. response to arbuscular mycorrhizae and fertilization. Journal of Sustainable Agriculture, 20 (1): 57-74.

Wu et al, (2011). Arbuscular mycorrhizal fungal colonization improves regrowth of bermudagrass (Cynodon dactylon L.) after cutting. Pakistan Journal of Botany, 43(1): 85-93.