Fungal mycelia and bacterial thiamine establish a mutualistic growth mechanism

Abstract

Physical spaces and nutrients are prerequisites to the survival of organisms while few interspecies mutual strategies are documented that satisfies them. Here we discovered a mutualistic mechanism between filamentous fungus and bacterium, Aspergillus nidulans and Bacillus subtilis. The bacterial cells co-cultured with the fungus traveled along mycelia depending on their flagella and dispersed farther with the expansion of fungal colony, indicating that the fungal mycelia supply space for bacteria to migrate, disperse and proliferate. Transcriptomic, genetic, molecular mass and imaging analyses demonstrated that the bacteria reach the mycelial edge and supply thiamine to the growing hyphae, resulting in a promotion of hyphal growth. The thiamine transfer from bacteria to the thiamine non-auxotrophic fungus is directly demonstrated by stable isotope labeling. The simultaneous spatial and metabolic interactions demonstrated in this study, reveal a mutualism that facilitates the communicating fungal and bacterial species to obtain environmental niche and nutrient respectively.

Let’s Get Physical: Bacterial-Fungal Interactions and Their Consequences in Agriculture and Health

“…As the field of bacterial-fungal interactions grows, we begin to understand the implications that these interactions have not only on the microorganisms, but also on plant and human hosts. This review shows that there are several areas of overlapping commonalities between BFIs in agriculture and clinical settings, including the use of fungal structures for bacterial dispersal [ 11 , 62 , 63 , 73 ], using ECM for bacterial attachment [ 14 , 18 ], and developmental changes that can occur in both fungi and bacteria [ 43 , 49 ] ( Figure 2 ). It is possible that there are even more commonalities that have yet to be discovered, including endosymbiosis in clinical settings.…”

“…Numerous emerging reports show bacterial movement along hyphae in various niches [ 62 , 63 ], influenced by the physicochemical properties of the microhabitats, in addition to the inherent characteristics of the BFIs [ 64 ]. In most cases, bacteria show chemotaxis towards the fungus and employ flagellar-mediated motility for movement, with minor roles for T3 and T4SS.…”

“…This confirmed the long-standing hypothesis that water films on hyphal surfaces facilitate bacterial movement, as aerial hyphae cannot support bacterial migration [ 64 ]. B. subtilis requires its flagella to travel back and forth along the mycelium of A. nidulans and promotes hyphal growth through the production of thiamine [ 62 ]. With the improvement in microscopic techniques, along with novel in situ methods, many more BFIs in diverse niches are sure to be identified in the near future [ 75 ].…”

Activity of Selected Group of Monoterpenes in Alzheimer’s Disease Symptoms in Experimental Model Studies—A Non-Systematic Review

“…In turn, the breakdown of CTFβ leads to formation of Aβ (released into the extracellular space) and the intracellular domain (AICD). AICD can travel to the nucleus, where it can affect gene expression and induce cellular apoptosis [ 16 , 17 ]. Aβ can be constructed from 40–42 amino acids, depending on where the γ-secretase cleaves the protein chain [ 18 , 19 ].…”