Cold stress is a major environmental challenge that severely limits rice production, especially during the early stages of growth. Low temperatures can harm leaf and root development, cause wilting or seedling death, and ultimately lead to significant yield losses. However, it remains poorly understood how rice leaves and roots coordinate their responses to cold stress.

In a study published in Plant Physiology and Biochemistry, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences have uncovered the molecular and physiological mechanisms behind cold sensitivity in a specialized rice line derived from common wild rice (Oryza rufipogon). The findings provide insights into how different plant organs (leaves and roots) respond to low-temperature stress, offering potential pathways for breeding more resilient rice varieties.

The researcher developed introgression lines (ILs) using Dianjingyou 1 (DJY1), a cultivated rice variety, as the recipient parent. Among these lines, one named J876 was selected to study cold tolerance at the seedling stage. Phenotypic analysis showed that J876 was significantly more sensitive to cold stress than DJY1.

By comparing the cold-sensitive line J876 with the cold-tolerant control variety DJY1 at the seedling stage, the researchers identified key differences in physiological, biochemical, and molecular responses. They revealed coordinated regulatory pathways in leaves and roots that contribute to chilling tolerance.

The results showed that under low temperatures, J876 accumulated higher levels of reactive oxygen species (ROS), while its antioxidant enzyme activities were reduced, indicating a weaker capacity to manage oxidative stress. They identified phenylpropanoid metabolism as a key secondary metabolic pathway involved in rice’s response to cold stress.

The researchers also found that although leaves and roots share common strategies for coping with cold stress, they show distinct response patterns. In J876 leaves, flavonoid biosynthesis was specifically suppressed under cold stress, whereas in roots, galactose metabolism was uniquely modulated.

The study highlights that impaired ROS scavenging and disruptions in cell wall-related metabolic pathways,particularly flavonoid production in leaves and galactose metabolism in roots, are key contributors to cold sensitivity in J876. The authors propose that boosting these organ-specific pathways could enhance cold tolerance in rice.

“Our findings show that cold stress responses are not uniform across the plant. To develop truly cold-tolerant rice, we may need to consider leaf- and root-specific regulatory networks, especially those governing ROS balance and cell wall integrity,” said XU Peng of XTBG.

Oryza rufipogon (Image by ZHU Renbin)

Available online: 19 May 2026