The potato rhizoplane actively recruits Fusarium taxa during flowering

Abstract

In recent years, the incidence of Fusarium wilt in potato plants has steadily increased, in the Middle Volga Region of Russia. The current work aimed to investigate the structure of root mycobiota of the Zhukovskij rannij potato cultivar and assess the effect of growth stage on Fusarium populations in different compartments of the potato root. Using Amplicon-Based Next Generation Sequencing and relevant bioinformatic tools, we compared fungal communities and guilds of the bulk soil (alfisol) and root compartments (rhizosphere, rhizoplane) of potato plants at flowering vegetation and senescence. Root compartments were inhabited by 3 major phyla: Ascomycota (79.41–94.84%), Basidiomycota (2.27–7.68%), and Mucoromycota (1.32–9.81%) irrespective of the stage of development. Fusarium was among the dominant genera of the rhizosphere (11.07 ± 0.99) and rhizoplane (37.61 ± 0.77%) during flowering, while at senescence they were replaced by the closely related genus Monographella (42.38–43.80%), the abundance of which significantly superseded other taxa in the fungal community. Unlike the root, Fusarium populations in the bulk soil did not change, which confirms the role of the potato plant in assembling fungal taxa and guilds. FUNGuild analysis showed that the near root zone of the studied cultivar is highly populated with pathotrophs, irrespective of the growth stage. Thus, the alfisol of the studied region is densely populated with pathotrophs, and the concurrent assembly of phytopathogens and beneficial fungi by the root demonstrates that the recruitment process of alfisol-based symbionts may be insufficient in preventing the influx of pathotrophs during root mycobiome formation in the studied potato cultivar.