Fungal sensing of host environment

Abstract

Summary To survive inside a host, fungi have to adapt to a changing and often hostile environment and therefore need the ability to recognize what is going on around them. To adapt to different host niches, they need to sense external conditions such as temperature, pH and to recognize specific host factors. The ability to respond to physiological changes inside the host, independent of being in a commensal, pathogenic or even symbiotic context, implicates mechanisms for sensing of specific host factors. Because the cell wall is constantly in contact with the surrounding, fungi express receptors on the surface of their cell wall, such as pheromone receptors, which have important roles, besides mediating chemotropism for mating. We are not restricting the discussion to the human host because the receptors and mechanisms used by different fungal species to sense their environment are often similar even for plant pathogens. Furthermore, the natural habitat of opportunistic pathogenic fungi with the potential to cause infection in a human host is in soil and on plants. While the hosts' mechanisms of sensing fungal pathogens have been addressed in the literature, the focus of this review is to fill the gap, giving an overview on fungal sensing of a host‐(ile) environment. Expanding our knowledge on host–fungal interactions is extremely important to prevent and treat diseases of pathogenic fungi, which are important issues in human health and agriculture but also to understand the delicate balance of fungal symbionts in our ecosystem.

Differential Proteomic Profiles of Pleurotus ostreatus in Response to Lignocellulosic Components Provide Insights into Divergent Adaptive Mechanisms

“…In a previous study, sensing of glucose as the preferred carbohydrate source was extensively studied in the yeast model organism (Braunsdorf et al, 2016). In the presence of glucose, genes required for growth on alternative carbon sources are repressed (Bahn et al, 2007).…”

Microfluidic monitoring of the growth of individual hyphae in confined environments

“…This arrested growth could be seen as an illustration of a quorum sensing phenomenon between hyphae, which is poorly understood and studied in fungi, but has been shown to exist in N. crassa and to control fungal growth in other species [37]. More precisely, quorum sensing limits fungal growth in order to regulate cell density and avoid competition for nutrients [30]. A seemingly related behaviour was also observed in some microchannels where fungal growth started late: the simultaneous growth of two hyphae in opposite directions, one of them originating from the perfusion chamber that had been reached by faster neighbours.…”

“…Apart from water, fungal growth requires nutrients such as glucose, ammonium, aminoacids, phosphates and trace elements, and gases such as oxygen, carbon dioxide and ammonia [28][29][30]. In response to the fluctuations of nutrient availability, fungi have developed strategies, such as the glucose transport system in N. crassa [31].…”

Fungal growth is affected by and affects pH and redox potential (Eh) of the growth medium

“…Fungal plant pathogens need to get resources from the plant and for doing so they need to live in the specific environment of plants, with an host species ranging from broad for generalists to narrow for specialist (Braunsdorf et al, 2016;Zeilinger et al, 2016;van der Does & Rep, 2017). Getting a better understanding of the interaction between pathogens and their host plants might open new ways to control plant diseases.…”