OsJAZ9 overexpression improves potassium deficiency tolerance in rice by modulating jasmonic acid levels and signaling

Abstract

Potassium (K) which makes around 2-10% of plants total dry biomass, when become deficient, makes the plants highly susceptible to both abiotic and biotic stresses. Recent evidences suggest overlapping transcriptional responses to K deficiency and Jasmonate (JA) treatment in plants. However, a link between these responses was missing. Notably, K deficiency and JA application produce similar phenotypic and transcriptional responses. Here, we used molecular, physiological and morphological studies to analyze the role of OsJAZ9 in JA homeostasis, K deficiency and sheath blight resistance. We raised OsJAZ9 overexpression, knockdown, translational reporter and C-terminal deleted translational reporter lines in rice to establish the role of JA signaling in K ion homeostasis and OsJAZ9 as a critical component of JA signaling for K deficiency response. OsJAZ9 overexpression and knockdown provide K deficiency tolerance and sensitivity, respectively, by modulating various K transporters and root system architecture. Furthermore, RNA Seq and JA profiling revealed an elevation of JA responsive genes and JA levels in OsJAZ9 OE lines under K deficiency. Our data provide clear evidence on the crucial role of JAZ repressor, OsJAZ9 in improving K deficiency tolerance in rice by altering JA levels and signaling.