Studies On Signal Transduction Mechanisms Of The Resistance To Rhizomania With Emphasis On Signaling Of Salicylic Acid And Ca²⁺ In Sugar Beet

Sugar beet(Beta vulgaris L.) is an important sugar crop in the world,but its yield and quality are attacked severely by many diseases.Sugar beet rhizomania disease is the best severious in the sugar beet.It caused by Beet necrotic yellow vein virus and transmitted by the soil-borne parasite Polymyxa beta. For soluting rhizomania disease ,The mechanism of resistance to Rhizomania was investigated in sugar beet.The signal function of the signal transduction introduction of SA,H₂O₂ and Ca²⁺ as signal molecule and signal transduction process were attracted more attention also studied.The results showed as follows:1. Effect of Rhizomania on antioxidant system(Superoxide dismutase,SOD;Peroxidase POD)and Hydrogen peroxide( H₂O₂),hyp,lignin of sugar beet cell wall were studied.The result showed that the content H₂O₂ was higher than that of the normal growth condition; Under the infected of Rhizomania,SOD activity,POD activity,the content of lignin and hyp of resistant varieties were higher than susceptible varieties.This result showed : there exist a close relationship between resistance to Rhizomania and the content H₂O₂ of cell wall on sugar beet.2. The salicylic acid plays an important role in plants disease resistance.Effects of rhizomania on the content of salicylic acid, pathogenesis-related protein,H₂O₂,lignin and Catalase(CAT) activity, Phenyllalanine ammonialyase (PAL) activity of sugar beet were studied.The result showed that the content salicylic acid, H₂O₂,pathogenesis-related protein, lignin were higher than that of the normal growth condition;Under the infected of rhiaomania, Catalase(CAT) activity, Phenyllalanine ammonialyase (PAL) activity of resistant varieties were higher than susceptible varieties.Catalase(CAT) activity, Phenyllalanine ammonialyase (PAL) activity.This result showed :salicylic acid is the one of signal transduction .3. Effects of 3 inhibitors of Ca²⁺ (EGTA,LaCl3 and W7) on the content oCalmomdulin (CaM),antioxidant system,Superoxide radical (O2-) production rate, H₂O₂ and soluble protein content were studied in sugar beet,cultivated in rhizomania contaminated soil and infected by Beet necrotic yellow vein virus.The results showed that the regular of the change Ca²⁺ is same with CaM;SOD activity,PODactivity, Catalase(CAT) activity,Ascorbic acid peroxidase(APX) activity and soluble protein content decreased while O2- production rate increased. It indicated a close relationship between resistance to rhizomania and Ca²⁺- CaM.The other signal functions in resistance to rhizomania are going on.