Fungal symbionts of tropical trees

Abstract

The lush green vegetation of moist tropical forest is not what it appears. Dissolve away all the plant matter from the dense foliage, giant buttressed trunks, tangled lianas, and sinuous roots, and a ghostly fungal shadow of the forest will remain. These fungi-diverse symbionts that include mutualists, commensals, and parasites-play critical roles in the dynamics, diversity, structure, and functions of tropical forests. The last two decades have led to an appreciation for the ubiquity and diversity of fungal symbionts, and to much speculation about their impacts. Understanding the nature and scope of their impacts on tropical diversity, plant growth and recruitment, and species interactions requires untangling the connections that fungi establish between their host plant and other species and the environment. This Special Feature explores these themes through analysis of the patterns and roles of tropical fungal symbionts along several dimensions: from mutualists to commensals to pathogens; from the forest canopy to the dark understory to the soil; from a postage-stamp sized piece of leaf to ecosystems; from seeds to leaves to roots. Through studies of an array of endophytes, epiphytes, and pathogens, we are better able to see tropical vegetation as a plant-fungus chimera and to critically explore the complex roles of fungi in tropical forests.