Effect of ionizing radiation on the bacterial and fungal endophytes of
the halophytic plant Kalidium schrenkianum
Endophytes are microbes found within tissues of plants in various types
of terrestrial and aquatic ecosystems, including those habitats with
ionizing radiation. Our study investigates the differences in
composition of bacterial and fungal endophytes associated with the
halophytic plant Kalidium schrenkianum and the effects of geochemical
factors and radiation (at low, medium, high level and control) on the
community structure of endophytic bacteria and fungi. The bacterial
class Actinobacteria and the fungal class Dothideomycetes predominated
the endophytic communities of K. schrenkianum. Aboveground parts had
higher fungal diversity while belowground parts had higher bacterial
diversity. Soil pH, total nitrogen, and organic matter showed
significant effects on the diversity of root endophytes. Radiation had
no significant effect on the abundance of different bacterial classes.
Sordariomycetes predominated the root fungal microbiota under high
radiation intensity. Differences in the endophytic communities between
aboveground and belowground parts were more than that between the
radiation levels. No significant differences were found in the
aboveground bacterial communities among the radiation levels. Radiation
showed a significant effect on the fungal co-occurrence networks.
Negative correlations were found between endophytic bacteria and fungi
in the plant. The genetic diversity of both endophytic bacteria and
fungi was higher in radioactive environments. Our findings suggest that
the endophytes associated with aboveground and belowground parts of K.
schrenkianum follow different mechanisms for community assembly and
different paradigms in stress response.