Soil microbes (in terms of functional gene content) are key drivers of ecosystem functions, but their functional characterization and their ecological insights are not sufficiently understood. It is necessary to understand how soil microbes ameliorate the nutrient stress environment and maintain their activity to support ecosystem multifunctionality in tropical forests.
In a study published in Science of the Total Environment, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences tried to evaluate the spatial pattern of nitrogen (N) and phosphorus (P) cycling functional genes and find out their potential influence on the aboveground plant community in a hyper-diverse tropical forest ecosystem in Xishuangbanna.
The researchers targeted N-cycle functional genes such as NirK, AOA, and AOB (molecular markers for detecting denitrifiers and ammonia oxidizers) and P-cycle functional gene PhoD (molecular marker to assess organic phosphorus mineralization).
By performing extensive soil sampling and vegetation data collection, the researchers detected higher spatial variability with a maximum magnitude of abundance for PhoD gene followed by NirK, AOA, and AOB. The PhoD gene abundance was positively correlated with soil N:P ratio and only PhoD gene showed a direct positive impact on the plant biomass.
They further found that PhoD gene community is high under phosphorus limiting conditions to provide a sufficient supply of available phosphorus required by plants for their growth. This indicates that microbes are being recruited in the soil environment according to the demand of the ecosystem.
“Therefore, in-depth spatial monitoring of microbial functions is required for identifying the microbial mechanisms of performing ecological functions (nutrient cycling, stress resistance, plant productivity, litter decomposition), their adaptation strategies to disturbances such as nutrient limiting conditions, and their contributions (cooperate or compete) to the plant community,” said YANG Xiaodong of XTBG.
He noted that the preliminary study improved the understanding of how microbial functional genes-environment associations could be used for monitoring soil health and its overall impact on ecosystem multifunctionality.