The symbiotic association between green plants and fungi is called
mycorrhiza. The plant makes organic products by photosynthesis and supplies them to
the fungus, and the fungus from the soil supplies water and mineral nutrients, such as
phosphorus, etc., to the plant. These fungi establish a mild form of parasitism, a form
of mutualism, where both the plant and the fungus benefit from the association.
Mycorrhizal fungi are soil fungi that play an important role in plant growth, protection
of plants from pathogens, and improving the quality of the soil. Abiotic components
and living communities of soil and soil organisms, particularly microbes, can have
direct and indirect impacts on land productivity. Direct impacts are those where
specific organisms affect the crop yield immediately. Indirect impacts that affect the
functions include those provided by soil organisms participating in carbon and nutrient
cycles, soil structure modification, and food web interactions that generate ecosystem
services that ultimately affect plant productivity. Selected organisms from different
functional groups, like microsymbionts (symbiotic fungi, bacteria, etc.), decomposers,
elemental transformers, soil ecosystem engineers, soil-borne pests and pathogens, and
micro regulators, are used to illustrate the linkages between soil biota and ecosystem
processes. There are various groups of fungi that form different types of symbiotic
associations with almost all groups of plants, from bryophytes to seed plants, i.e.,
gymnosperms and angiosperms, on the earth. Out of the seven types of mycorrhizae
(ectomycorrhizae, ectendomycorrhizae, ericoid mycorrhizae, arbuscular mycorrhizae,
orchidoid mycorrhizae, arbutoid mycorrhizae, and monotropoid mycorrhizae), the
endomycorrhizae (arbuscular) and ectomycorrhizae are the most abundant and
widespread. The molecular basis of nutrient exchange between ectomycorrhizal and
arbuscular mycorrhizal fungi and host plants proved the role of mycorrhizal fungi in
disease control, the alleviation of heavy metal stress, and increasing production in
sustainable agriculture, horticulture, and forest plants or trees, etc. Arbuscular
mycorrhizal fungi play a major role in the restoration of native ecosystems, and
mycorrhizae transform a disturbed ecosystem into productive land. Ectomycorrhizae
play an important role in forestation, forest ecosystems, and horticultural systems, and
they maintain monodominance in tropical rainforests. Apart from the nutrient benefits
to the plants,the mycorrhizae are presently employed in the colonization of barren soil and improving the transplantability of forest plants. Mycorrhizae create resistance
against insect pests, various root diseases, toxicity, and reduced susceptibility in plants.
The presence of mycorrhizae also favours the growth of beneficial microbiota,
converting the rhizosphere into a mycorrhizosphere and increasing tolerance to adverse
conditions like drought, salinity, and stress in the plants.
