Scientists have found out that variations among antibiotic-producing bacteria in tropical forest soils play a key role in biodiversity.
A study published on October 28 in the journal Biotropica said the impact of these microorganisms on tropical plant communities and ecosystems is significant, particularly in areas where “plant diversity, competition and pathogen pressures are high.”
Researchers from the University of Minnesota, led by Kristen Becklund, discovered that the antibiotic production of these soil bacteria was “widespread” even as the abundance of the microorganisms differed markedly in many areas, depending partly on nutrient availability.
This finding is important in tropical countries like the Philippines, which already hosts 5 percent of all the plants in the world, and where a variety of antibiotics has been discovered and used for various medicines. It is significant as well in view of the interest shown by the Philippine government, the Southeast Asian Regional Center for Research and Graduate Study in Agriculture (Searca) to promote upland agriculture, including in areas that had been logged over and could be transformed into agroforestry zones that feature forest canopies and cash crops cultivated under large trees.
The production of antibiotics from the soils in tropical forests represents a big plus for farmers and upland dwellers, Searca Director Dr. Gil C. Saguiguit Jr. said.
Upland agriculture is one of the topics to be discussed in the 2014 International Conference on Agricultural and Rural Development to be held at the Makati Shangri-La Hotel on November 12 and 13.
Saguiguit said that besides antibiotics from the soil, the more than 1 million hectares of old growth forests and even secondary forests might also host a number of substances with distinct pharmaceutical applications. If these antibiotic-laced soils can kill diseases, then they may have the capacity to stop the spread of soil-based pathogens and, thus, help improve plant health and even increase yield of crops, Saguiguit said.
“Our results suggest substantial differences in the capacities of microbial communities to suppress soil-borne diseases in tropical forests,” Becklund said.
“The fact that we are seeing all this variation is exciting because it means that these bacteria may be influencing diversity in tropical forests.”
They added that differences in the capacities of microbial communities to suppress soil-borne diseases could affect the composition of forests themselves.
Antibiotics harbored by the soil are believed to be capable of killing their competitors, including pathogens and can even result in the development of disease-suppressive soils.
The researchers noted that since different plants are susceptible to different pathogens and diseases, the variation in the abundance, effectiveness and specificity of microbially produced antibiotics may influence not only plant diseases and yield but also the composition of the tree species in the forests itself.
“This study is an initial step to open the black box of microbial community function in tropical forest soils,” they said.