Natural Bacteria Fertilise Tree Branches

While bacteria in the human body plays a major role in its nutrition, obesity, and immunity, the role of the microbiome of plants and their role in symbiosis has not been understood.

A new study by University of Washington researchers shows that poplar trees in rocky, inhospitable terrain containing bacteria fertilize them and enable their growth through valuable nutrients. Moreover, the microbial communities are diverse, with variations among the plants.

"This variability made it especially difficult to quantify the activity, but is the key to the biology since it is probably only specific groupings of microorganisms that are working together to provide this nutrient to the host," said Sharon Doty of the University of Washington and lead author of the study.

While nitrogen fixation is a vital process for life, low-nutrient environments such as rocky regions need bacteria support for nitrogen fixation and supply of nutrients. The fixation occurs in the bacteria-rich root nodules of plants, where the bacteria convert the nitrogen in the air into accessible nutrients for the plants.

The new study suggests that symbiotic nitrogen fixation process is possible not only in roots but even in the branches of trees.

The team isolated microbes originating from wild poplar and willow plants. They benefit the growth of corn, tomatoes and peppers and can also help the farm industry by stimulating crop growth with fewer fertilizers.

While fertilizers are created from fossil fuels, the costs can vary a lot. Their widespread use in the growth of diverse crops makes them important to the agricultural industry.

"Having access to the key microbial strains that help wild plants thrive on just rocks and sand will be crucial for moving agriculture, bioenergy and forestry away from a dependence on chemical fertilizers and towards a more natural way of boosting plant productivity," Doty said.

The findings were published in the May 19 issue of the journal PLOS One.