OsIMA1 enhances tolerance to cadmium stress in rice

Abstract

Iron (Fe) is crucial for the growth and development of plants and cadmium (Cd) is toxic to plants. There is an antagonistical mechanism between Fe and Cd uptake in plants. OsIMAs are a class of small peptides, and their overexpression improves Fe accumulation in rice. To explore the role of OsIMA genes in response to Cd stress, we analyzed the expression of two OsIMA genes by qRT-PCR, generated OsIMA1 overexpression plants and CRISPR/Cas9 edited ima1 mutants by genetic transformation, assessed the plant heights of OsIMA1 overexpressing plants and ima1 mutant plants under Cd stress, and measured the Fe and Cd concentration of root and shoot. The results were as follows: (1) Transcriptional levels both OsIMA1 and OsIMA2 were up-regulated by Cd treatment. (2) Overexpression of OsIMA1 gene improved the tolerance of plants to Cd stress. (3) The loss-of-function of OsIMA1 led to the higher sensitivity of plants to Cd stress. (4) OsIMA1 overexpressing plants accumulated more Cd in the root and the ima1 mutants accumulated more Cd in the shoot. To sum up, OsIMA1 improves Cd tolerance by restricting Cd translocation from root to shoot, which provides the theoretical reference for breeding the Cd-tolerant rice.

Keywords

• rice
• osima
• cadmium
• iron
• antagonism