Changes in Cell Ultrastructure in Maize Leaves Infected by Maize Dwarf Mosaic Virus

Ultrastructural alterations in foliar cells were studied in leaves of resistant maize variety Luyu16 and susceptible maize inbred line Luyuan92 infected by maize dwarf mosaic virus Shandong isolate (MDMV-SD), respectively. The results showed that marked cytopathological alterations were observed both in resistant plants and in susceptible plants, compared with that in healthy plants. However, some ultrastructural alterations, which observed in resistant plants, were different from those in susceptible plants. In resistant plants, which infected with the virus, the main organelles, including chloroplasts and mitochondria, were slightly destroyed, the amount of mitochondria and peroxisome were increased. A few or no plasmodesmata were observed. There were three kinds of inclusions including pinwheel, bundle and laminated aggregate, and the virus particles in the cytoplasm. In susceptible plants, which infected with the virus, the chloroplasts were heavily disrupted, including thylakoid swelling and envelope broking. The virus particles were more than those in the resistant variety. Four kinds of inclusions including pinwheel, bundle, laminated aggregate and high electon-dense body appeared in cytoplasm. Plasmodesmata and plasma membrane were abundant, and there were frequent invaginations of the plasma membrane that led to the formation of vesicles and myelin-like structures.