| Brassinosteroids(BRs)is a polyhydroxy sterol compound with a very high biological activity and is recognized as the sixth largest phytohormone in the world.It is involved in many processes that regulate plant growth and development,while also playing a role in plant response to biotic and abiotic stresses.Rice(Oryza sativa)is one of the most important food crops in the world.Its yield and quality are related to the survival of most people.Nilaparvata lugens St?l(BPH)is an important pest in rice production.One.Based on the transcription factor OsDLT(DWARF AND LOW-TILLERING)downstream of the brassinolide signaling pathway,this paper studied the regulated rice defense signal network.The results are as follows:(1)Compared with wild-type rice at the same developmental stage,the mutant rice dlt was more tolerant to the feeding hazard of brown planthopper.At the same time,the selective experiment of brown planthopper in wild type rice and 48-day-old dlt rice at different developmental stages indicated that brown planthopper was more likely to endanger wild-type rice at various developmental stages.(2)Overexpression of OsDLT gene increased the sensitivity of rice to brown planthopper,and overexpression of OsDLT reduced the evasion of rice feeding and spawning of female adults of the brown planthopper,and the content of honeydew in the newly emerged female adult was significantly increased.The developmental period of Nymphalidae nymphs was significantly shortened,and the number of eggs laid by F1 and the hatching rate of eggs increased significantly.(3)Compared with untreated 9311,the female adults of the brown planthopper tend to feed and lay eggs on the 24-epicastasterone(ECS)-treated rice,while the female adults of the brown planthopper were untreated and ECS-treated.The OsDLT function does not have a preference for feeding and spawning between mutant rice dlt.Propiconazole(PCZ)is a plant BR synthesis inhibitor.Compared with untreated 9311,the adult larvae of the brown planthopper have significantly reduced feeding and egg production on PCZ treated 9311 rice,while compared with untreated dlt mutant rice.In comparison,the feeding and eggproduction of female adults of brown planthopper on PCZ treated dlt rice increased significantly.Compared with the untreated 9311 rice,the sensitivity of the Bikinin-treated9311 rice to the female adults of the brown planthopper was significantly reduced.The dlt mutant,Bikinin treatment increased the feeding and oviposition sensitivity of the female adults of the brown planthopper.(4)After transcriptome data analysis,7196 differentially expressed genes were obtained.The differentially expressed genes in the brown rice planthopper feeding process9311 rice(WB)and dlt rice(dB)were analyzed.A total of 18 genes in the jasmonic acid pathway were up-regulated,accounting for 81.83% of the differentially expressed genes in this pathway.A total of 15 genes were differentially expressed in the salicylic acid pathway,and 11 of them were up-regulated in 73.33% of the differentially expressed genes in the salicylic acid pathway.The 18 defense-related WRKY families accounted for 85.71% of the WRKY family differentially expressed genes,and all of the 9 ERF family differentially expressed genes were up-regulated.Three disease-related protein proteins and five chitinases were significantly up-regulated.(5)The construction of the yeast two-hybrid system demonstrated that the OsDLT protein itself does not self-activate and screens for three genes that interact with the OsDLT protein.Then,four activation plasmids of the JAZ family gene of jasmonate inhibitor were cloned and constructed,and OsJAZ6 and OsDLT proteins were confirmed to interact by yeast two-hybridization.This study shows that OsDLT plays an important role in the defense response induced by brown planthopper,and OsDLT may be involved in the interaction between the two hormonal pathways of jasmonic acid pathway and brassinolide pathway affecting rice defense response. |
