Researchers have discovered a soil bacterium that helps citrus plants grow by releasing a natural chemical signal that improves the plant’s ability to take up nutrients. The finding could lead to new biological products designed to improve citrus tree health and fertilizer efficiency.
An article about the study was published in Horticulture Research. The authors are Hongfei Li, Dongxin Liu, Huailong Teng, Lile Deng, Bo Zheng, Qiang Xu, Xiuxin Deng and Zhiyong Pan with Huazhong Agricultural University in China, and Shunyuan Xiao with the University of Maryland.
The research focused on plant growth-promoting rhizobacteria (PGPR) — beneficial microbes that live around plant roots. Scientists identified a citrus-associated bacterium, Burkholderia sp. Burk_2H3, that produces a compound called N-(3-oxooctanoyl)-L-homoserine lactone (PGPHL). This compound acts like a communication signal between the bacteria and the plant, encouraging citrus roots to become more effective at absorbing important nutrients.
When researchers applied PGPHL to citrus seedlings, the plants produced more biomass, with dry weight increasing by about 43% compared with untreated plants. Additional testing showed the treatment increased the activity of genes linked to nutrient transport in roots and resulted in higher levels of nitrogen, phosphorus and potassium in plant tissues.
For citrus growers, the research highlights the growing importance of the soil microbiome — the community of microorganisms living around roots. Healthier relationships between citrus trees and beneficial microbes could eventually provide new tools to help trees use fertilizers more efficiently, develop stronger root systems and improve overall plant growth.
The researchers also tested PGPHL on other crops under field conditions. Biomass improvements were reported in pepper, celery and mustard, suggesting the compound may have broader agricultural applications as a future plant growth stimulant or biofertilizer.
The research is still in the early stages. The citrus work was conducted primarily with seedlings under controlled conditions. Additional studies are needed to determine how well the technology performs in mature commercial groves, different soil types and under stresses such as drought or huanglongbing.
For growers, the takeaway is that future citrus production may increasingly rely on biological tools that work alongside traditional nutrition programs. Instead of simply adding more fertilizer, growers may eventually be able to use targeted microbial products that help trees better capture and use available nutrients.
Read the full research here.
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