The structure of mycelial cords and rhizomorphs of fungi: A mini-review

Abstract

Fungi are ubiquitous - they are found in any conceivable environment, i.e., both aquatic and terrestrial habitats. They remain one of the most diverse groups of organisms on Earth. Because fungi are heterotrophic, they obtain their nutrients by colonizing their substrates with a vegetative mass of hyphae called mycelium. These hyphae secrete enzymes that digest nutrients locked in colonized substrates, after which the nutrients are then absorbed by the hyphae. Not only do hyphae constitute the mycelium of fungi, but they also form other structures - mycelial strand, mycelial cords, and rhizomorphs - through which fungi are able to spread in their environment in search of new substrates to colonize. The aim of this present paper is to explore the structure of mycelial cords and rhizomorphs. Rhizomorphs are among the most complex organs produced by fungi. They are root-like structures constituted by a series of differentiated tissues each with distinctive hyphal type, orientation, size, and function. Thus, rhizomorphs are produced as a result of a coordinated growth of millions of bundled hyphae. Rhizomorph-forming fungi thrive in nutrient-poor environment and are known to cause devastating destruction to homes and plantations. Because rhizomorphs serve as exploratory organs, and they enhance the survival of rhizomorph-forming fungi in plantations and homes, farmers, homeowners, attorneys, and even mycologists and plant pathologists, need to understand and appreciate their potential to wreak havoc that results in huge annual financial losses.