Functional Involvement of a Mitogen Activated Protein Kinase Module, OsMKK3-OsMPK7-OsWRK30 in Mediating Resistance against Xanthomonas oryzae in Rice

Abstract

Mitogen-activated protein kinases (MAPKs) are highly conserved signaling modules in eukaryotes, transmitting signals from upstream receptor to downstream target by phosphorelay mechanism. Here we report involvement of a poorly characterized group C MAPK of rice namely, OsMPK7 along with its upstream MAPK kinase, OsMKK3 and downstream target, OsWRKY30 during Xanthomonas oryzae infection, a causal agent of leaf blight disease in rice. X. oryzae infection resulted in induction of OsMPK7 and OsMKK3. OsMKK3 was found to physically interact and phosphorylate OsMPK7. Overexpression of OsMPK7 and OsMKK3, individually and in combinations resulted in inhibition of disease symptoms caused by X. oryzae, however silencing of OsMPK7 resulted in disease susceptibility. Furthermore, OsWRKY30 was identified as downstream target of OsMPK7 through protein-protein interaction techniques and was found to be a positive regulator of defence response against X. oryzae pathogen. The overexpression of OsMKK3-OsMPK7 upregulated genes involved in pathogenesis, cell wall structure maintenance and cell metabolism indicating possible mechanism of disease resistance. These leaves also showed restricted movement of the pathogen from the point of infection to uninfected area. Taken together, this work suggests a positive involvement of OsMKK3-OsMPK7-OsWRKY30 module in imparting disease resistance against X. oryzae infection in rice.

Nuclear Signaling of Plant MAPKs

“…Group C MAPKs have been poorly characterized. Recently, the group C MAPK OsMPK7 and its upstream MAPKK OsMKK3 were shown to positively regulate resistance against Xanthomonas oryzae infection, known to cause leaf blight disease in rice (Jalmi and Sinha, 2016 ). In addition, the transcription factor OsWRKY30 interacts with and is phosphorylated by OsMPK7.…”

“…In addition, the transcription factor OsWRKY30 interacts with and is phosphorylated by OsMPK7. OsWRKY30 is also involved in the resistance to X. oryzae , suggesting that a module composed of OsMKK3-OsMPK7-OsWRKY30 contributes to leaf blight disease resistance in rice (Jalmi and Sinha, 2016 ).…”

Suppression of a leucine‐rich repeat receptor‐like kinase enhances host plant resistance to a specialist herbivore

“…OsWRKY89 positively regulates SA accumulation and resistance in rice to WBPH (Wang et al, 2007). OsWRKY30 interacts with many OsMPKs and can be phosphorylated by OsMPK3, OsMPK7 or OsMPK14 (Jalmi & Sinha, 2016;Shen et al, 2012). Moreover, it is an SA-inducible gene and can upregulate OsWRKY45, and positively regulates disease resistance in rice (Han et al, 2013).…”

Proteomic Analysis of Kiwifruit in Response to the Postharvest Pathogen, Botrytis cinerea

“…Plant MAPK cascades play important roles in plant defense mechanisms against pathogen attack. MAPK cascades are involved in signaling multiple defense responses, such as the induction of plant defense hormones, ROS generation, defense gene activation, cell wall strengthening, and hypersensitive response (Jalmi and Sinha, 2016 ; Lee and Back, 2017 ).…”