1974 年 24 巻 1 号 p. 57-63
Experiments were carried out to examine the effect of the extract of the salivary gland of Myzus persicae Sulzer on broad bean epidermal cells infected with bean yellow mosaic virus (BYMV). The extract had been obtained by homogenizing the organ in distilled water.
The extract of the salivary gland had an effect of producing microscopic changes in healthy and diseased epidermal cells. This effect was severer against virus-infected cells than non-infected cells. The most remarkable change in infected cells was the appearance of plasmolysis. This plasmolytic activity of the salivary gland extract was not destroyed by heat treatment.
Virus inclusions in infected cells were granulated and diffused by the action of the extract. The cells plasmolyzed by the extract were different in shape from those plasmolyzed with 0.8M sucrose solution or 0 8M KNO3 solution. There was no significant difference in plasmolysis induced with the sucrose solution between healthy and diseased cells. The salivary gland extract was therefore presumed to act on virus-infected cells in a specific manner.
The extracts of intestine, stomach, brain, and oesophageal ganglion caused mild plasmolysis of infected cells. They were, however, much weaker in plasmolytic activity than the salivary gland extract. Moreover, when exposed to this extract, the infected epidermal tissue decreased in virus activity.
These results suggest that the saliva may play an important role on the transmission of the virus by the aphid; that is, by the influence of the saliva on infected cells, it may be difficult for the aphid stylet to acquire virus particles from these cells. The extent of the salivary effect would be determined by the interaction between the saliva and the plant cell. Therefore, the action of the saliva is presumed to be the cause of the low transmission of BYMV by aphid feeding.