Identification And Functional Analysis Of Hydrogen Peroxide Regulating Plant Downstream Genes In Arabidopsis Thaliana Disease Resistance

Under the long-term interaction between plants and pathogenic microorganisms,complex defense mechanisms have evolved in plant.Reactive oxygen species?ROS?are important signaling molecules in plants that respond to external stressors such as drought,pests and diseases.Including photorespiration way to produce hydrogen peroxide?H₂O₂?is in the ROS has the best stability and strong activity of free radicals,and mediates the plant immune response related to salicylic acid?SA?.H₂O₂ is involved in plant disease resistance.It plays a vital role in the discovery and identification of H₂O₂ components in plant immune responses,which is particularly critical for people to understand the mechanism of plant response to stress.Catalase2?CAT2?is the most important scavenging enzyme to scavenge H₂O₂.Arabidopsis mutant?cat2?is the best material for studying the plant resistance mediated by H₂O₂ as signal regulation SA and analyzing the signal transduction mechanism of H₂O₂ in the SA disease resistance pathway.In this study,the Arabidopsis cat2 mutant was chemically mutagenized by ethyl methanesulfonate?EMS?,and the inhibitor of cat2 phenotype?spontaneous cell death?was screened.The inhibition of child with backcross parentage cat2,the F₂ generation separation ratio was about 3:1.and it is speculated that the cell death suppressor genes in the chromosome,and for the stealth mutations.The physiological and biochemical preliminary detection of the cell death inhibitor has a higher level of oxidation in the plant.The mutation of this gene does not affect the accumulation of H₂O₂,and may be located downstream of H₂O₂ as a signal.Mixed pool sequencing was performed on F₂ generation of cell death suppressor backcrossing,and Q30 data representing the error rate showed good sample quality.The comparison data of the Arabidopsis genome library showed that the average depth of the parents was 20 and16,and the average depth of the F₂ generation was 46 and 49,the coverage rate is above98%.The mutation site is detected and calculated for the candidate region,located on the first chromosome.Four candidate genes were obtained by screening candidate sites and statistical distribution of mutation sites in the genome.The candidate genes and mutation site design corresponding to primer sequencing The initially selected mutation gene is a nuclear pore protein:NUA.A NUA vector carrying green fluorescent protein was constructed,and the positive seedling showed that the NUA protein was localized to the nuclear membrane.The T-DNA insertion mutant?nua-3?of the gene was hybridized with cat2 to obtain pure and mutant materials,The double mutant nua-3 cat2 did not show SA-induced cell death,and it was preliminarily determined that the nucleoporin is involved in H₂O₂-mediated SA-induced plant disease resistance caused by photorespiration.Therefore,this study intends to use a combination of genetics,regenerator pool sequencing,molecular biology,cell biology and other techniques to screen the H₂O₂-mediated SA-related pathway induction using the model plant Arabidopsis thaliana as a genetic material.A key component of the leaf cell death program,to explore the H₂O₂disease resistance signal network,systematically study the regulation mechanism of H₂O₂in plant disease resistance,and provide a theoretical basis for improving crop stress resistance.