Work

Exogenous proline mediates OsNPR1 to regulate the innate pool of IAA in response to Cr exposure in rice plants

Year: 2025

Type: article

Abstract: Indole acetic acid (IAA) orchestrates a myriad of physiological and biochemical responses in plants under stressful conditions, highlighting its indispensable role in plant resilience. The widespread contamination of chromium (Cr) poses a significant threat to rice cultivation, as its accumulation in plants disrupts various metabolic processes, consequently hindering growth. Of course, the utilization of exogenous growth regulators, including proline (Pro), has notably surged as a strategy to mitigate stress in plants. Pro can trigger the activation of other growth-regulating molecules, including IAA, to coordinate stress responses. To explore the complex interaction between exogenous Pro and the endogenous pool of IAA under Cr(VI) toxicity, a hydroponic system was established. The rice plants treated with exogenous Pro in coupled with Cr(VI) [Cr(VI)+Pro] showed significantly greater content of IAA than the plants not treated with exogenous Pro [Cr(VI)-Pro]. The expression analysis of genes involved in the speciation of IAA reactions reveals that the downregulation of OsNPR1 under “Cr(VI)+Pro” treatments might be the crucial player in increasing the IAA content in rice plants. The increase in IAA by Pro treatment under Cr toxicity might lead to an improvement in root activity and root architecture elements. Importantly, no significant difference was observed in the accumulation of Cr in [Cr(VI)-Pro]- and [Cr(VI)+Pro]-treated rice plants. These results reveal that exogenous Pro can improve plant growth by inducing IAA accumulation in plant tissues exposed to Cr(VI) toxicity, without increasing Cr toxicity in plants. • IAA is key hormone in mediating the response to Cr toxicity in rice plants. • Exogenous Pro induced IAA content in rice by down-regulating OsNPR1 under Cr(VI) exposure. • Increased IAA level improved root system architecture under “Cr(VI)+Pro”. • Cr content slightly reduced in shoots but increased in roots under “Cr(VI)+Pro”.

Source: Ecotoxicology and Environmental Safety

DOI: 10.1016/j.ecoenv.2025.117955

Authors: Abid Ullah, Peng Tian, Yi Kang, Xiao-Zhang Yu

Institution: Guilin University of Technology

Language: English

Topic: Chromium effects and bioremediation

Subfield: Health, Toxicology and Mutagenesis

Field: Environmental Science

Domain: Physical Sciences

SDG: Zero hunger

Open Access status: gold

Estimated APC paid: $3,650