Shift of Bacterial Community in Synanthropic Mite Tyrophagus putrescentiae Induced by Fusarium Fungal Diet

Abstract

Background Tyrophagus putrescentiae (Acari: Astigmata) and Fusarium sp. co-occur in poorly managed grain. In a laboratory experiment, mite grazing resulted in significant reduction of fungal mycelium on cultivation plates. The destruction of mycelium appeared to be a result of an interaction between the mites, fungi and associated bacteria.Methodology and Principal FindingsA laboratory experiment was performed to simulate a situation of grain multiinfested by mites and Fusarium fungi. Changes of mite-associated bacterial community in T. putrescentiae were described in 3 habitats: (i) T. putrescentiae mites from a rearing diet prior to their transfer to fungal diet; (ii) fungal mycelium before mite introduction; (iii) mites after 7 day diet of each Fusarium avenaceum, F. culmorum, F. poae and F. verticillioides. Bacterial communities were characterized by 16 S rRNA gene sequencing. In total, 157 nearly full-length 16 S rRNA gene sequences from 9 samples representing selected habitats were analyzed. In the mites, the shift from rearing to fungal diet caused changes in mite associated bacterial community. A diverse bacterial community was associated with mites feeding on F. avenaceum, while feeding on the other three Fusarium spp. led to selection of a community dominated by Bacillaceae.Conclusions/SignificanceThe work demonstrated changes of bacterial community associated with T. putrescentiae after shift to fungal diets suggesting selection for Bacillaceae species known as chitinase producers, which might participate in the fungal mycelium hydrolysis.

Experimental Manipulation Shows a Greater Influence of Population than Dietary Perturbation on the Microbiome of Tyrophagus putrescentiae

“…The Koppert population was associated with high numbers of Bacillaceae with similarity (90 to 99%) to Virgibacillus. The Sanger sequencing of the 16S rRNA previously identified sequences with similarity (94 to 99%) to Virgibacillus after a diet shift from SPMd to a fungal diet (37). These Bacillaceae include bacteria that produce enzymes facilitating the utilization of nutrients by the mites (18).…”

“…These Bacillaceae include bacteria that produce enzymes facilitating the utilization of nutrients by the mites (18). Bacterial exoenzymes are active against difficult-to-digest structural polysaccharides such as cellulose and chitin (18) and are increased in the bacterial communities of T. putrescentiae on Fusarium diets (37). Bacillus cereus isolates originating from dog kernels infested by T. putrescentiae produce alkaline and neutral proteases (38).…”

Feces Derived Allergens of Tyrophagus putrescentiae Reared on Dried Dog Food and Evidence of the Strong Nutritional Interaction between the Mite and Bacillus cereus Producing Protease Bacillolysins and Exo-chitinases

“…Mites are associated with microorganisms, including bacteria and fungi. The bacteria and fungi contribute to mite nutrition by producing exo-enzymes that predigest the substrate by serving directly as a food source (Sinha, 1966 ; Hubert et al, 2003 , 2012a , b ; Smrz, 2003 ; Erban and Hubert, 2008 ; Naegele et al, 2013 ). From a sanitary view, the mite feces are the most significant contaminants of the human environment because they contain major allergens that accumulate and persist in the environment (Tovey et al, 1981 ; de Boer et al, 1995 ; Sidenius et al, 2002 ; Platts-Mills and Woodfolk, 2011 ).…”

Carpoglyphus lactis(Acari: Astigmata) from various dried fruits differed in associated micro-organisms

“…The astigmatid mites are inhabited by bacteria, which are suggested as symbiotic or parasitic, or as a food source (Hubert et al . ,b; Kopecky et al . , ; Zindel et al .…”