Scientists have long known that bacteria in and on the human body are essential for health, playing a role in nutrition, obesity and disease protection. However, only recently have experts begun to examine the role of the microbiome of plants and their role in symbiosis.
A new study by University of Washington researchers reveals that poplar trees in rocky, inhospitable terrain possess bacteria inside them that fertilize them and likely help them grow through the provision of valuable nutrients. Furthermore, these microbial communities are very diverse, with significant variation observed between each plant.
"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.
One of the most important natural processes for life is nitrogen fixation. However, in low-nutrient environments such as rocky terrains, plants must rely on bacteria to conduct nitrogen fixation and provide them with the nutrients that they need.
Nitrogen fixation typically takes place in the bacteria-rich root nodules of plants, and it is here that bacteria aid these roots in converting atmospheric nitrogen into a form that can be harnessed by the plant.
Although previous research suggests that only plants with root nodules can benefit from this kind of nitrogen fixation, the new study suggests that this symbiotic nitrogen fixation process can also occur in tree branches without the help of root nodules.
The microbes that the team isolated during the study - which originate from wild poplar and willow plants - are beneficial to the growth of corn, tomatoes and peppers and could help the agricultural industry by providing a way to stimulate crop growth with less fertilizer.
Given the fact that fertilizers are created from fossil fuels, costs can vary greatly, and their widespread use in the growth of many different kinds of crops makes them a key facet of 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.
