New molecular mechanism that improves plant growth and tolerance to nutritional stress

In the 1960s, during the Green Revolution, improved crop yields were partly due to smaller varieties with lower levels of gibberellins (GA), growth-promoting phytohormones, and higher levels of DELLAs, growth-inhibiting nuclear regulatory proteins. However, because DELLAs reduce the acquisition and assimilation of nitrogen (N), the productivity of these varieties depends on N fertilizers, an agricultural practice that increases production costs and leads to environmental and health problems.

Plant growth is influenced by nutrient availability. Carbon (C) and nitrogen (N) are the most abundant elements in plant cells, and their assimilation and metabolism are interdependent, profoundly impacting gene expression, plant architecture, growth, and yield. However, the interaction between C and N pathways has been understudied. Imbalances in this C/N ratio, caused by soil nutrient deficiencies, such as N limitation in agricultural soils, or by environmental factors, such as high CO₂ levels, negatively affect crop survival and yield. In response to this C/N stress, plants trigger a specific response that reduces growth and increases anthocyanin accumulation.

The study, published in the journal The Plant Cell by the ‘Growth and stress responses during early plant development’ group, reveals how the C/N stress further enhances DELLA accumulation and reduces GA levels compared to N limitation. This overaccumulation of DELLAs is counteracted by the E3-ligase protein (ATL31) in the membrane, preventing excessive DELLA buildup that could negatively impact survival metabolism or growth recovery after the stress subsides.

A new strategy to improve growth and C/N stress tolerance

This new mechanism has several implications: although DELLAs accumulate in the nucleus after stress, we have demonstrated their degradation in the cytosol due to their interaction with the membrane-bound protein ATL31. This novel association adds complexity to the well-known GA-mediated degradation pathway. Furthermore, manipulating DELLA levels typically results in stunted plants, but increasing ATL31 expression reduces DELLA levels and improves growth and C/N stress tolerance without altering development under balanced C/N conditions. This suggests that manipulating ATL31 levels allows for modulating DELLA-mediated stress responses with less impact on plant development.

Future studies of the group will determine the degree of conservation of the ATL31 pathway in crops and how its molecular components function. These results will allow for the design of crop varieties that require less nitrogen (fertilizer) and are more tolerant to stress without yield loss, thus reducing production costs and environmental impact..

A comment “In Brief” for this article is available at

Chia, J.-C. 2026. A GA-independent, membrane-associated pathway regulates DELLA degradation during carbon/nitrogen stress. The Plant Cell koag037. DOI: 10.1093/plcell/koag037