Rice clock synchronizes nitrogen supply.

The relationship between the biological clock of plants and the microorganisms present in the soil may play an important role in the efficiency of soil use. Nitrogen in the culture of riceAccording to a publication by Professor Leandro Simões Azevedo Gonçalves, from the State University of Londrina (UEL), a study by Du et al. (2026), published in the journal Cell Host & Microbe, showed that the plant is able to synchronize the activity of the rhizosphere microbiota with periods of higher demand for the nutrient.

The mechanism involves the Nhd1 gene, also called OsCCA1, a component of the rice circadian clock. It controls the rhythmic release of exudates from the roots and, in this way, interferes with the activity of microorganisms near the plant. The process allows the microbial production of ammonium, NH₄⁺, to coincide with times of greater absorption by the rice.

In the experiments, NH₄⁺ absorption increased during the day and peaked near dusk. In plants with a mutation in the ndh1 gene, this rhythm continued, but with less intensity. Removal of the microbiota also reduced absorption, while its reintroduction restored the observed pattern.

The study also identified the involvement of quercetin 3-gentiobioside, or Q3Gen, a flavonoid released by roots and regulated by Nhd1. The substance acted on microbial genes linked to the nitrogen cycle and increased the availability of NH₄⁺.

Based on this mechanism, the researchers developed a consortium with Pseudomonas chengduensis and Brevundimonas bullata. In the field, the use of the consortium increased productivity and nitrogen use efficiency, but the benefit disappeared in the mutant plants. The results indicate that the development of bio-inputs may depend not only on the microorganisms used, but also on the ability of the plant genotype to recruit them and activate their functions at the appropriate time.