The harsh environment on the northern slope of the Kunlun Mountains means that limited plant species can survive under these conditions.

Legumes generally have a high tolerance to stress, including damage caused by wind-blown sand. They can stabilize soils and enhance soil fertility, thus becoming one of the main plant families in the region. Bacteria in root nodules of legumes play important roles in promoting plant growth.

Dr. ZENG Fanjiang's group from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences investigated root nodule-associated bacteria isolated from leguminous plants along an elevation gradient on the northern slope of the Kunlun Mountains.

The researchers obtained 300 isolates from seven legume species within six ecological zones. They identified isolates based on 16S rRNA gene phylogenetic analysis and further identified potential rhizobia using a recA gene phylogeny.

Among the isolates, Bacillales (particularly Bacillus) were the dominant isolates from all host legumes and all elevations (63.5%), followed by Rhizobiales (13%) and Pseudomonadales (11.7%). A few elevation-specific patterns emerged within the Bacillales and Pseudomonadales.

Rhizobiales isolates were obtained from five different host legumes spanning the entire elevation gradient. Those from the low-elevation Qira Desert-Oasis Transition Zone (1,350-1,960 m) suggested some patterns of host preference.

The study shows that most bacteria associated with root nodules of legumes are widely distributed in distinct ecological zones within a single geographic region, and both climate and host interactions may influence their distributions.

The results of the study were published in Frontiers in Microbiology.