Abstract
Boron (B) is an essential micronutrient for plant growth and development. Jasmonic acid (JA) plays pivotal roles in plant growth. However, the underlying molecular mechanism of JA involvement in B-deficiency-induced root growth inhibition is yet to be explored. In this study, we investigated the response of JA to B deficiency and the mechanism of JAR1-dependent JA signaling in root growth inhibition under B deficiency. B deficiency enhanced JA signaling in roots, and root growth inhibition was partially restored by JA biosynthesis inhibition. jar1-1 (jasmonate-resistant 1, JAR1) mutant, mutants of coronatine-insensitive 1 (coi1-2) and myc2 defective in JA signaling showed insensitivity to B deficiency. Ethylene-overproduction mutant eto1 and ethylene-insensitive mutant etr1 showed sensitivity and insensitivity to B deficiency, respectively, suggesting that ethylene is involved in the inhibition of primary root growth under B deficiency. Furthermore, after a declined in EIN3 protein levels, which may contribute to root growth, ethylene signaling was weakened in the jar1-1 mutant root under B deficiency. Under B deficiency, B concentrations were increased in the roots and shoots of the jar1-1 mutant, owing to the large root system and its activity. Therefore, our findings revealed that JA, which is involved in the inhibition of root growth under B deficiency, is regulated by JAR1 activated JA and ethylene signaling pathways.
Boron deficiency-induced root growth inhibition is mediated by brassinosteroid signalling regulation in Arabidopsis
