Mechanism Of CIPK31 And Its Interacting Protein Regulating Rice Disease Resistance

Rice is an important food crop in China.The fungal disease is a major threat to the safe production of rice.Rice blast caused by Magnaporthe geisea and sheath blight caused by Rhizoctonia solani are two main fungi diseases in rice production,and the damage is particularly serious.The interaction mechanism between host and pathogen is complex,and the host broad-spectrum disease resistance mechanism needs to be further analyzed,but a clear understanding of the interaction mechanism is conducive to accurate disease prevention and control.Therefore,in the process of rice disease control,it is necessary to strengthen the study of host-pathogen interaction mechanism,and the results will provide a scientific basis for the breeding of disease-resistant varieties.In this study,a broad-spectrum resistance gene cipk31 was identified,and the genetic verification of CIPK31 resistance function,protein domain analysis,screening of interaction proteins and the mechanism of rice resistance to rice blast and sheath blight regulated by its interaction proteins were carried out.The results are as follows:1.Through the identification and inoculation verification of cipk31 mutant,it was found that cipk31 mutations aggravated the occurrence of rice blast and sheath blight.Overexpression of CIPK31 enhanced the resistance of rice to rice blast and sheath blight.The results showed that CIPK31 was regulating the resistance of rice to rice blast and sheath blight.Subcellular localization analysis showed that CIPK31 was located in cytoplasm and nucleus.After analysis of its protein domain,it was found that its protein structure had typical characteristics of CIPK family,including C-terminal PPI domain,NAF domain and N-terminal kinase domain.CIPK31 is a typical CIPK kinase family gene and has broad-spectrum disease resistance potential.2.Through yeast two-hybrid and bimolecular fluorescence complementary test,the proteins interacting with CIPK31 were identified as CBL2,AKT1L,PP2A,VOZ and TCP19transcription factors.3.In the study on the resistance mechanism of rice to rice blast,the results of cluster analysis and protein structure identification of AKT1L showed that it was very similar to AKT1.AKT1 participated in the regulation of K~+uptake and played a positive role in the resistance of rice to rice blast.It is speculated that AKT1L may also be a potassium channel protein.The content of K~+in cipk31 mutants was significantly lower than that in wild type DJ.Spraying different concentrations of KCl on wild type could significantly improve the resistance of rice to rice blast.CIPK31 interacts with CBL2 and AKT1L,and plays a positive regulatory role in rice resistance to rice blast.The results of this study revealed the mechanism that CBL2-CIPK31-AKT1L signal transduction pathway is regulating rice resistance to rice blast.4.In the study on the mechanism of rice resistance to sheath blight,the effect of CIPK31interaction protein on rice resistance to sheath blight was analyzed.The results showed that PP2A increased the resistance to sheath blight by regulating the expression of rice defense genes,VOZ transcription factors positively regulated rice sheath blight resistance,while TCP19 transcription factors negatively regulated rice sheath blight resistance.To sum up,this paper illustrates that CIPK31 is a potential positive regulator of broad-spectrum resistance in rice.Several proteins interacting with CIPK31 were screened.Among them,CIPK31-CBL2-AKT1L signal pathway plays a role in rice resistance to rice blast and sheath blight,while the interaction of CIPK31 with VOZ,PP2A and TCP19 plays a role in rice resistance to sheath blight.The mechanism of positive regulation of rice sheath blight resistance by CIPK31,PP2A and VOZ,the negative regulation of TCP19 in rice sheath blight and the binding domain of TCP19 transcription factors were analyzed in detail.Differentially expressed genes in tcp19 mutants and overexpressed plants were screened,and the promoter binding sequences of differential genes were analyzed in order to explore a more in-depth mechanism.The results not only broaden a new field of vision for the study of the molecular mechanism of rice disease resistance,but also provide new targets and genetic resources for rice disease resistance breeding.