Mobilization of micronutrients by mycorrhizal fungi

Abstract

Mycorrhizal fungus constitutes heterogeneous fungal taxa embracing an array of plant species. This group is found allied with the roots of beyond 90% of the plant species in this world. There is a range of mycorrhizal associations, among which arbuscular and ectotrophic mycorrhizal interactions are of high biological and economic significance. This chapter gives details about habitation, host range, and structural components of these mycorrhizal groups, along with a meticulous discussion on the mineral absorption, mechanisms involved in different absorption pathways. In addition to enhancement of mineral nutrient uptake by plants in soil, several mycorrhizal fungi execute an important task in mobilizing mineral nutrients from inaccessible organic substrate, mineral particles, and rock surfaces. Mycorrhizal fungi adopt various methods to achieve the purpose effectively, like greater area of absorption for the roots of plant, liberation of biochemical compounds, and consortium with different microbes. Furthermore, mycorrhizal fungi also provide an imperative C sink in soil other than mobilizing nutrients, consequently playing an important role in the cycling of these mineral elements. The role of every partner in a mycorrhizal association is to be exposed by the application of molecular and genetic tools, coupled with high-throughput sequencing and advanced microscopy. The signaling pathways between plants and fungi have recently been elucidated, and recognition of a range of novel nutrient transporters has unveiled a number of cellular processes which are fundamental to the mycorrhizal symbiosis. Various transporters, particularly proton-coupled phosphate transporters, have been documented on both the fungal and plant membranes which contribute to transmission of phosphate from fungi to plants. Even though much work has been formerly done on several aspects, such as symbioses, the extent to which these are functionally essential in agriculture remains uncertain. It is a vital need to spotlight on the questions, whose answers will offer novel perspectives on mycorrhizal utility.