UP scientists identify plant boosting bacteria in bamboo and corn

By Eunice Jean C. Patron

Farmers usually use chemical fertilizers to grow their crops, but these can be expensive and may harm the environment.

A more efficient and cheaper alternative is the use of specific microorganisms called plant growth-promoting bacteria (PGPB).

PGPB help plants absorb more nutrients and produce growth hormones that boost crop production. Using PGPB as biofertilizers can provide the same benefits as chemical fertilizers—without the harmful effects.

Camille Andrea Flores, Dr. Maria Auxilia Siringan, and Mary Ann Cielo Relucio-San Diego from the University of the Philippines – Diliman College of Science’s Natural Sciences Research Institute (UPD-CS NSRI) screened and identified bacterial strains with potential plant-beneficial traits from bamboo and corn roots grown in Cagayan province, for possible development into biofertilizers.

Bamboo and corn are known to harbor PGPB in their roots.

“Corn is one of the most in-demand grains in the world and the second most valuable staple in the Philippines. Bamboo is an economically significant and high-value crop in the country, with the Philippines being the 5th leading exporter of bamboo globally. Increasing the yield of these crops could boost our economy,” Relucio-San Diego said.

A total of 27 bacterial strains were collected and identified through DNA analysis. These bacteria were tested in the laboratory to determine their plant-growth promoting abilities.

Results showed that all the strains exhibited at least two beneficial traits. Four had genes for nitrogen fixation, including dinitrogenase reductase (nifH); 11 could solubilize phosphate in the soil, helping plants absorb it more effectively; all 27 produced indole-3-acetic acid (IAA), a natural plant hormone that promotes growth; and 24 produced siderophores, which help plants absorb iron.

Notably, two standout strains—Enterobacter roggenkampii B1-01 and Klebsiella oxytoca B1-04—exhibited all of the beneficial traits tested, demonstrating that bamboo and corn roots can host diverse bacteria capable of promoting plant growth, with potential applications in agriculture.

“If these microorganisms can be developed into a biofertilizer, they could help farmers improve the yield and quality of their crops,” Relucio-San Diego added. She noted, however, that this would require a long process involving additional funding, manpower, and appropriate facilities.

The first step in developing these strains into commercial biofertilizers is ensuring that the microorganisms used do not pose a threat to any form of life, especially humans and the environment. This involves checking whether they carry genes associated with human diseases or antimicrobial resistance.

“Next is determining whether the microorganisms can improve plant growth, as observed in our in vitro tests and predicted by their genomic features. The best way to do this is through in planta or pot experiments,” Relucio-San Diego explained.

During pot experiments, the microorganisms are introduced to a specific plant model to assess their effects on plant growth (e.g., root elongation, increased biomass, stem elongation, etc.).

These experiments must then be verified through appropriate tests before progressing to field trials. Only after successful field trials can these strains be developed into commercial biofertilizers.

The paper, titled “Multiple Plant Growth–Promoting Activities Exhibited by Root-Associated Bacteria Isolated From Bamboo and Corn,” was included in the International Journal of Microbiology, an open access journal publishing papers on microorganisms and their interaction with hosts and the environment.

The research was also funded by NSRI, and the whole-genome sequencing was supported by Project 4, Probing Microbial Diversity in Submarine Groundwater Discharge (SGD) of the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD).

References:

Flores, C. A., Siringan, M. A., & Relucio-San Diego, M. A. (2025). Multiple plant growth–promoting activities exhibited by root‐associated bacteria isolated from bamboo and corn. International Journal of Microbiology, 2025(1). https://doi.org/10.1155/ijm/6374935