Sex-specific competition differently regulates the response of the rhizosphere fungal community of Hippophae rhamnoides–A dioecious plant, under Mn stress

Abstract

In this study, we investigated the soil physicochemical parameters and responses of rhizospheric fungal communities of Hippophae rhamnoides to Mn stress under different sexual competition patterns. The results showed that competition significantly affects soil physicochemical properties, enzyme activity, and rhizosphere-associated fungal community structures. Under Mn stress, soils with intersexual competition had higher levels of N supply than those with the intrasexual competition. Moreover, fungal communities under intersexual interaction were more positive to Mn stress than intrasexual interaction. Under intrasexual competition, female plants had higher total phosphorus content, neutral phosphatase activity, and relative abundance of symbiotic fungi in soils to obtain phosphorus nutrients to alleviate Mn stress. In contrast, male plants had relatively stable fungal communities in soils. In the intersexual competition, rhizosphere fungal diversity and relative abundance of saprophytic fungi in male plants were significantly higher than in female plants under Mn stress. In addition, female plants showed greater plasticity in the response of rhizosphere microorganisms to their neighbors of different sexes. The microbial composition in soils of female plants varied more than male plants between intrasexual and intersexual competition. These results indicated that sex-specific competition and neighbor effects regulate the microbial community structure and function of dioecious plants under heavy metal stress, which might affect nutrient cycling and phytoremediation potential in heavy metal-contaminated soils.

Seedling performance in a dioecious tree species is similar near female and male conspecific adults despite differences in colonization by arbuscular mycorrhizal fungi

“…For example, positive effects due to AM fungal association may help seedlings counter conspecific distance‐ and density‐dependent mortality due to pathogens (Liang et al 2015, Bachelot et al 2017; reviewed by Zahra et al 2021), via either increases in plant growth or nutritional status (Smith and Read 2008; reviewed by Delavaux et al 2017) or activation of plant defensive pathways (Newsham et al 1995, Pozo and Azcón‐Aguilar 2007). Some, but not all, dioecious and gynodioecious species exhibit sex‐specific responses to mycorrhiza (Varga and Kytöviita 2008, 2010a, b2010b, Eppley et al 2009, González et al 2015; reviewed by Vega‐Frutis et al 2013); thus, it's unclear whether mycorrhizal abundance, composition, and seedling colonization typically varies in the soil beneath male and female plants (Hood et al 2004, Li et al 2020, Lin et al 2023) or leads to differences in seedling performance (Varga and Kytöviita 2010b, Varga et al 2013). It's also unclear if mycorrhizal association is more strongly influenced by the density of conspecific seedlings or by the presence of large conspecific plants.…”