Analysis Of Maize R. Solani AG1-IA-induced Differential Proteins

Maize banded leaf and sheath blight(BLSB) is caused by Rhizoctonia solani Kuhn and is the most destructive disease of Maize.The disease harms Maize near the ground sections of the leaf sheath and stem,causes corruption of caudex,ruins conductting tissue,affects the transportion of water and nutrition,so it results in significant yield loss.It increased and spreaded in recent years in China.And the disease has been the target of domestic disease resistance breeding.The breeding cycle of conventional methods to select resistant varieties is too long.With the prevalence of pathogens,the pathogenicity of physiological race and the interaction between pathogens with plants are easily changed.Therefore useing new technologies to in-depthly research the infection and resistant mechanisms is of great significance to solve the problem of plant diseases.This research used high tolerance maize inbreed lines of R15 and high infection lines of ye478.The pathogen was high pathogenic fungus anastomosis groups AG1-IA of Rhizoctonia solani Kuhn.At the jointing stage in greenhouse,two wheat seeds colonized by AG1-IA were placed into the third sheath of the maize plants.At 12 hrs,24 hrs,36 hrs,48 hrs and 72 hrs of the post-inoculation,the third leaf was picked down to extract total proteins.The uninoculated leaf was the check materials.The different symptoms showed that R15 had better resistance to AG1-IA.Its infection time was about 24 hrs after inoculation,and the large area infection time was about 48h after inoculation.Ye478 had poorer resistance to AG1-IA.About 12 hrs after inoculation it had been infected,24 hrs had shown symptoms of expanded infection,and 36 hrs～48 hrs was the larg area infection period.It was about the same with the other results in our research group.The 2-DE system was part of optimized:lysis adding thiourea enhanced the solubility of proteins;repeated washing and precipitating,and salt bridge reduced the affection of the salt; concentration gradient of standard proteins instead of the volume gradient reduce experimental error.15 differential protein spots was found from 2-DE map.Peptide mass fingerprintings had been got by MALDI-TOF/MS.After searching and comparing in database,five points higher than threshold and some points,which had function,was identifyed.Shikimate kinase I, cytokinin receptor histidine kinase,ferredoxin-thioredoxin reductase catalytic chain(FTR-C) and CDC48 was increased expression;the ribulose-bisphosphate carboxylase/oxygenase (Rubisco) large subunit,ATP synthase CF1-αsubunit and potosystem I reaction center subunit N was reduced expression. Shikimate kinase was involved in the synthesis of aromatic amino acid,then its increased expression could synthesis more flavonoids and lignin to enhance plant resistant ability. Cytokininand ethylene signal transduction pathway exists some overlap,after infection, increased cytokinin could trigger part of ET resistant system.FTR was a common redox system.It played a key role in the regulation of anti-oxidation and reduction.Plants could increase the FTR to remove the outbreak reactive oxygen species after infection.These proteins in R15 were expressed more than ye478,so R15 showed haigher disease-resistant than ye478.CDC48 involved in ER-associated protein degradation.It showed that after infection the cell of maize began to be destroyed.Rubisco was the key enzyme of CO₂ fixation in the process of photosynthesis,and involved in the carbon cycle in plants;ATPase involved in the electronic transmission of cells is the key enzyme of energy conversion;potosystem I protein molecules used the light,changed CO₂ to carbon and oxygen,absorpted the solar energy and transmited electrons.The trend of the reduced expression of these proteins in ye478 was haigher than R15.It showed that after infection by Rhizoctonia solani AGI-IA,the material and energy metabolism of ye478 was inhibited or even be destroyed more seriously than R15.Comprehensively,after infection,maize increase expressed certain disease-resistant proteins or induced some resistance system,but material and energy metabolism at the same time was inhibited in a certain degree,and cell destructed.Integrated the results of expanded symptom,we could know that along with the aggravation,the trend of resistant proteins increased expression was inferior to the weakening trend of energy metabolism,then the plants was weaker and unable to resist the pathogen infection,leading to the death.