Study Of H₂O₂ From Plastid In Wheat Albinism Line

The stage albinism phenomenon of wheat?Triticum aestivum L.?FA85 could be induced by prolonged low temperature.Previous studies showed that some genes related to photosynthetic electron transport chain?ETC?,such as cytochrome Cyb6-f complex subunit genes,NDH complex subunit genes,ycf3,were down regulated at low temperature.All those may influence photosynthetic electron transport and will produce more H₂O₂ in plastid.In this research,we study whether the albinism line accumulated excessive H₂O₂,the relationship between excessive H₂O₂ and albino leaves and detected the content of anthocyanin in different strains in view of the red leaves in albinism line and analysis its albinism mechanism from oxidative and antioxidation.The following important results are obtained in this study:?1?Compared with Aibian No.1 at room temperature and low temperature,the albinism line accumulated much more H₂O₂,especially at prolonged low temperature.?2?The chlorophyll fluorescence parameters Fv/Fm,qP of wheat leaves at room temperature and at low temperature were measured by using Chlorophyll Fluorescence Imaging?CFI?system.The results suggest that the activity of PS?was inhibited and the electron transfer capacity of Albinism line may be destroyed at low temperature,which is a resource of high level of H₂O₂.?3?The content of H₂O₂ was detected and albino rate was counted after treating wheat seedings with methyl viologen?endogenous H₂O₂ inducer in plastid?at room temperature and low temperature.The results show that MV could induce the Aibian No.1 to be albino and enhance the albinism phenomenon of Albinism line at long-term low temperatures.At room temperature,MV cann't induce the wheat leaf turn white,but it will cause leaves turn yellow and even withered.These phenomena indicate that low temperature is required for the albinism of Albinism line and the content of H₂O₂ is directly related to its abino leaf.?4?The microarray data and qPCR analysis showed that the expression of HEMA2,HEMB1 was down regulated in the chlorophyll biosynthesis pathway,which will induce the accumulation of H₂O₂.Some genes such as APX4,t APX and HO1,related to scavenging H₂O₂,were significantly down regulated at low temperature.Clearly,the ability of scavenging H₂O₂ is significantly cut down in Albinism line.?5?The red leaf plants of Albinism line in the field have higher content of anthocyanin,while the content of white leaves of Albinism line and Aibian No.1 is very low.It is believed that the increasing content of anthocyanin with antioxidant activity is one of mechanisms of self-regulation against oxidative stress in Albinism line.The above results suggested that the accumulation of H₂O₂ in leaves of Albinism line is mainly caused by the generating of large amount of H₂O₂ in plastid and the decreased ability of scavenging,which is closely related to the albinism phenomenon induced by low temperature.