Some plant viruses are transmitted to new host plants via pollen. However, since the first report of pollen transmission of plant viruses in 1918, the fundamental mechanisms underlying this process have remained unresolved. Pollen transmission of plant viruses is classified into two types: vertical transmission via pollen and horizontal transmission via pollen. Recently, we have obtained important insights into these mechanisms. In vertical transmission via pollen, it was suggested that when virus-infected pollen grains germinate, the pollen tubes deliver the sperm cells required for fertilization into the embryo sacs while simultaneously introducing the virus, resulting in the formation of virus-infected seeds. In contrast, in horizontal transmission via pollen, it was suggested that pollen tubes that have accumulated the virus penetrate and elongate within the stigma, establishing the initial virus infection sites. The infection then expanded into the vascular tissues of the stigma and style, and subsequently spread throughout the plant via the phloem. Thus, pollenborne viruses are thought to exploit the sexual reproduction system of seed plants, using pollen as a vector to achieve both horizontal and vertical transmission. In this review, we provide an overview of our research conducted to date on the transmission mechanisms of pollen-borne viruses.
More than 40 years have passed since human immunodeficiency virus (HIV), the causative agent of acquired immune deficiency syndrome (AIDS), was isolated in 1983. In the early days of the epidemic, AIDS was feared as a deadly disease, but today, thanks to advances in anti-retroviral drugs, many infected individuals can maintain their health as long as they take their medication. Furthermore, advances in basic research have clarified why HIV is difficult to eliminate from the body and how it causes immune deficiency in infected individuals. This paper outlines the progress made over the past 40 years in the following areas: the discovery of HIV, HIV denialism, receptors and co-receptors, biases in HIV isolation, broadly neutralizing antibodies, and understanding the pathogenesis of AIDS.
The COVID-19 pandemic has spurred vigorous research in a field that is old but new, a fusion of aerosol science and virology, each with its own history. I tentatively refer to this interdisciplinary field as "aerosol virology". This review article aims to convey the appeal of research in this field to virologists unfamiliar with aerosol science, covering fundamental knowledge of aerosols. In fact, preceding this article, I had published in the Japanese Journal of Aerosol Science a companion review with this, titled "An Introduction to Aerosol Virology"1）, which included basic virological knowledge for members less familiar with viruses, aiming to spark their interest in the field. To advance "aerosol virology", it is necessary to approach research goals with knowledge of both aerosol science and virology, not just one field. This represents a largely unexplored frontier even for virology. I hope members of the Virology Society will venture into this frontier. Both reviews were written with this aspiration in mind.
