油菜黄单胞杆菌AhpC突变对被侵染菜豆叶片光化学反应特性的影响

该文研究了两种不同基因型的黄单胞杆菌[野生型( Xcp-W)和烷基过氧化物还原酶亚基C( AhpC)的缺失突变体( Xcp-ahpC)]侵染菜豆叶片( Phaseolus vulgaris)3 d后,叶片侵染位点以及同一叶片上距侵染位点不同距离处叶绿素荧光参数的变化。结果表明：与对照相比,两种病原菌侵染后叶片被侵染位点以及同叶距侵染位点一定距离处潜在最大光化学效率( Fv/Fm )的变化不显著,而光系统Ⅱ( PSⅡ)实际光化学效率[ Y(Ⅱ)]、电子传递速率( ETR)以及光化学猝灭系数( qP和qL )均显著降低。与野生型病原菌Xcp-W的侵染相比,Xcp-ahpC突变型菌株侵染后叶片的以上参数的降低更为明显。野生型病菌Xcp-W侵染对非调节性能量耗散产量[ Y(NO)]和调节性能量耗散产量[ Y(NPQ)]无显著影响；但Xcp-ahpC型病原菌侵染则导致了( Y(NO)和Y(NPQ)的显著上升。综上可知,白叶枯病菌侵染使得叶片光系统Ⅱ的光能使用效率受到了系统性的抑制,而病原菌烷基过氧化物还原酶亚基C的缺失对叶片光系统Ⅱ的光能使用效率的抑制作用更为强烈,并影响了植物的光能耗散机制。

Effects of the infection with Xanthomonas campestris pv. phaseoli with the mutation in AhpC on chlorophyll fluorescence characteristics of bean leaves

After the bean ( Phaseolus vulgaris) leaves were infected with two different genotypes of Xanthomonas campes-tris pv. phaseoli, either wild-type ( Xcp-W) or the mutant lacking Alkyl hydroperoxide reductase subunit C ( Xcp-ah-pC) , the changes of the chlorophyll fluorescence parameters in both the infected site and the locations distant from the infected sites were studied. The results showed that in the infected site and the locations distant from the infected sites,the potential maximal photochemical efficiency ( Fv/Fm ) did not significantly change, while photosynthesis systemⅡ(PSⅡ), actual photochemical efficiency [Y(Ⅱ)], electronic transmission rate (ETR), and the coefficient of photochemi-cal quenching (qP) were significantly decreased. The decreases of PSⅡ, Y(Ⅱ), ETR, and qP in the leaves infected with Xcp-ahpC were more drastic than those in the leaves infected with Xcp-W. The quantum yield of non-regulated energy dissipation (Y(NO)) and quantum yield of regulated energy dissipation (Y(NPQ)) of the leaves were not significantly af-fected by the infection with Xcp-W. But,Y(NO) and Y(NPQ) of the leaves were significantly increased by the infection with Xcp-ahpC. These results showed that the infection with bacterial blight pathogen can cause a systemic inhibition of the photochemical efficiency of PSⅡin bean leaves. And, this inhibition was more drastic when the leaves was infected by the pathogen lacking the Alkyl hydroperoxide reductase subunit C.