病原菌侵染下细胞外ATP对光系统Ⅱ光化学反应的调节作用

Regulation of the photochemical reaction of photosystemⅡby extracellular ATP under pathogen infection

以野生型Col-0和细胞外ATP(e ATP)受体突变型dorn1-3拟南芥为实验材料,探究e ATP在两种丁香假单胞菌(毒性Pst DC3000和非毒性Pstavr B)侵染下的水平变化以及对其光化学反应的调节作用.结果表明,Pst DC3000和Pstavr B侵染均导致拟南芥叶片中e ATP水平、光适应下叶片的最大光化学量子产率(F_(v)′/F_(m)′)、光适应下PSⅡ实际光化学效率(Y(Ⅱ))、光合电子传递速率(ETR)降低而非调节性能量耗散的量子产额Y(NO)升高.Pst DC3000侵染下,dorn1-3拟南芥植株F_(v)′/F_(m)′、Y(Ⅱ)、ETR略低于野生型,Y(NO)略高于野生型,但均未达显著性差异;在Pstavr B侵染下,dorn1-3拟南芥植株F_(v)′/F_(m)′、Y(Ⅱ)、ETR显著低于野生型植株,Y(NO)显著高于野生型.在病原菌侵染下,e ATP受体的突变会增强病原菌对PSⅡ的抑制作用,且在非毒性病原菌侵染下该效应更为明显.在非毒性病原菌侵染对植物光化学反应影响的过程中e ATP具有重要的调控作用.

In order to explore the changes in extracellular ATP(eATP)levels and regulation of photo-chemical reaction by eATP under pathogen infection,a wild type Col-0 and eATP receptor mutant dorn1-3 of Arabidopsis were used as experimental materials,and it was found that the infection with either virulent pathogen(PstDC3000)or avirulent pathogen(PstavrB)resulted in a decrease of eATP levels,values of the maximum photochemical efficiency under light adaptation(F_(v)′/F_(m)′),actual photo-chemical efficiency of PSⅡ(Y(Ⅱ))and photosynthetic electronic transmission rate(ETR),but an increase in the quantum yield of non-regulated energy dissipation(Y(NO))of the leaves.By a com-parison between wild type Col-0 and eATP receptor mutant dorn1-3 of Arabidopsis seedlings,it was revealed that,under PstDC3000 infection,the values of F_(v)′/F_(m)′,Y(Ⅱ)and ETR of dorn1-3 plants were slightly lower than those of the wild type,while the Y(NO)was slightly higher than those of the wild type.Under PstavrB infection,the values of F_(v)′/F_(m)′,Y(Ⅱ)and ETR of the dorn1-3 plants were signifi-cantly lower than those of wild type plants,while Y(NO)was significantly higher.The results above indicated that the mutation of eATP receptor could exacerbate the inhibition of the pathogen infection on the photochemical reaction of PSⅡunder pathogen infection,and such effect of the mutation of eATP receptor was more significant under PstavrB infection.It was suggested that eATP could play an impor-tant role in regulating the photochemical reaction of PSⅡunder pathogen infection.