Multitrophic Interactions Between Arbuscular Mycorrhizal Fungi, Foliar Endophytic Fungi and Aphids

Abstract

Almost all living plants can be simultaneously colonised by arbuscular mycorrhizal fungi in the roots and endophytes in the shoots, while also being attacked by insect herbivores. However, to date, no study has ever examined the multitrophic interactions between these two different fungal groups and insects on any species of forb. Here, we examined the effects of two commercial species mixtures of arbuscular mycorrhizal fungi (AMF) and two foliar endophytes (Colletotrichum acutatum and Cladosporium oxysporum) on the growth of an invasive weed, Impatiens glandulifera, and the aphids that attack it. AMF reduced plant biomass, which was most evident when C. oxysporum was inoculated. Mycorrhizal fungi had few effects on aphids, and these depended on the identity of the endophytes present. Meanwhile, endophytes tended to increase aphid numbers, but this depended on the identity of the AMF inoculum. Throughout, there were differences in the responses of the plant to the two mycorrhizal mixtures, demonstrating clear AMF specificity in this plant. These specific effects were also strongly affected by the endophytes, with a greater number of interactions found between the AMF and endophytes than between the endophytes themselves. In particular, AMF reduced infection levels by the endophytes, while some endophyte inoculations reduced mycorrhizal colonisation. We suggest that both AMF and endophytes could play an important part in future biological control programmes of weeds, but further multitrophic experiments are required to unravel the complexity of interactions between spatially separated parts of the plant microbiome.

Roles of Arbuscular mycorrhizal Fungi as a Biocontrol Agent in the Control of Plant Diseases

“…They can remain in animals and plants, enter the human body through the food chain, and endanger human health [ 2 ]. With the continuous improvement in people’s living standards, food safety problems caused by pesticides and fertilizers have received widespread attention [ 3 ]. Therefore, the search for green and environmentally friendly technologies to control plant diseases and insect pests has become one of the research hotspots of environmental scientists and plant pathologists [ 4 ].…”

“…Studies have shown that AMF can regulate the formation of secondary metabolites in host plants by changing the morphology or anatomical structure of plant roots, improving the physical and chemical properties of the rhizosphere environment, competing with pathogens for photosynthetic products and infection space, and activating disease resistance and defense systems in plants [ 12 ]. AMF can reduce the damage caused by fungi, nematodes, bacteria, and other pathogens of Cucumis sativus , Fragaria ananassa , Lycopersicon esculentum , Citrus reticulata , Olea europaea , Medicago truncatula , Cucumis melo , Zea mays , Solanum tuberosum , Musa nana , and other plants, and can also reduce the use of pesticides [ 3 , 4 , 6 , 7 , 10 , 13 ]. Biological control is technology that has received a great deal of attention [ 14 ].…”

Role of Mycorrhizae in Crop Protection

“…As much as this has been helpful, it has also resulted in nearly an uncontrollable levels of pesticide resistance among many plant pathogens. Also, their direct and indirect impacts have led to the destruction of non-target and beneficial soil organisms as well as raising various health concerns among human and animal populations [4,11]. To manage this, an appreciable number of studies in recent times have focused on identifying and engineering micro-organisms (i.e., mycorrhiza, bacteria, fungi, and nematodes) that are naturally antagonistic to various plant disease causing pathogens.…”

“…Many natural resources conservatives have called for reduction in the application of these pesticides and resort to natural, environmentally friendlier and healthy alternatives/practices that require reduction, if not complete their elimination [3,4]. Many biological, chemical and physical factors also influence soil quality, among these are the microbial communities in the rhizosphere that contribute to soil quality thereby enhancing plant growth and health [5,6].…”

Fungus Applications on Growth and Yield of Dena-1 Soybean Varieties

“…The activity of Trichoderma fungi in addition to producing various enzymes that can degrade organic matter which releases ionic compounds that can be exchanged by plant roots to meet their nutritional needs [12][13], also produces secondary metabolites [14][15] and various growth regulating compounds [16] which can help plant vegetative growth. Various arbuscular mycorrhizal fungi play an important role to improving soil structure and increasing plant nutrition [17]. Fungi Glomus etunicatum plays a role in promoting plant growth through a significant supply of various essential nutrients into plant tissues [18][19].…”