报告题目一：Plasmodesmata, not just holes in the wall（植物胞间连丝，不仅仅是细胞壁上的小孔）
报 告 人：Jens Tilsner博士，Lecturer及Group Leader，英国圣安德鲁斯大学
报告时间：2018年9月5日（星期三）9:00-11:00
报告地点：生命科学学院，新逸夫教学楼，608会议室
报告摘要：Plasmodesmata (PD) are nanopores that span the plant cell wall and connect the cytoplasm, plasma membrane (PM) and endoplasmic reticulum (ER) of neighbouring cells. They are essential for intercellular communication and domain formation during plant development. PD also serves as signalling hubs during defence responses against invading pathogens, and as conduits for the mobile RNA silencing signal. The permeability of PD is dynamically regulated. Small molecules such as metabolites and hormones can diffuse through the channels, but macromolecules such as proteins and RNAs are transported between cells in a more specific manner. Despite their importance for plant biology, only few PD components have so far been identified and the mechanisms of their functional regulation remain poorly understood.
The plasma membrane within PD shows distinct features such as a unique protein composition and lack of lateral diffusion. Segregation of PM domains in organisms possessing a cell wall depends strongly on PM-wall interactions. The cell wall around PD is also modified compared to the surrounding ‘bulk’ cell wall. Thus, PD may comprise areas where unique membrane-wall contacts mediate both the PM domain segregation and the specific cell wall architecture that underpin the functional properties of these nanopores.
Additionally, the ER within PD is possibly the most tightly constricted membrane tube found in nature, and connected to the PM by unidentified tethering proteins, which qualifies PD as a unique type of membrane contact site. The extreme biophysical properties of the two PD membranes, and the properties of the PD membrane tethering proteins will be crucial to understanding the molecular basis for cell-to-cell communication in plants.
报告题目二：Push on through to the other side, a new hypothesis for how Tobacco mosaic virus gets a few MDa through the cell wall（百万道尔顿分子量的烟草花叶病毒是如何穿过植物细胞壁的—一个全新的假说）
报 告 人：Jens Tilsner博士，Lecturer及Group Leader，英国圣安德鲁斯大学
报告时间：2018年9月13日（星期四）9:00-11:00
报告地点：生命科学学院，新逸夫教学楼，608会议室
报告摘要：Plant viruses are major crop pathogens threatening food security, especially in developing countries. All plant viruses transport their genome from infected to naïve cells through membranous channels called plasmodesmata, in order to spread throughout their host. The virus-encoded proteins mediating this transport have been identified >30 years ago, but the molecular mechanism by which nucleic acid molecules several megadalton in size are transported through the extremely narrow (<10 nm free diameter) channels has not been elucidated. recently, we have shown that the 30k transport protein of tobacco mosaic virus, the first described and paradigmatic plant virus movement protein, forms rna- and membrane-bound polymers that we hypothesize to act as molecular “injection needles” pushing viral genomes through plasmodesmata into uninfected recipient cells.
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附参考文献：
Folimonova, SY & Tilsner, J 2018, 'Hitchhikers, highway tolls and roadworks: the interactions of plant viruses with the phloem' Current Opinion in Plant Biology, vol. 43, pp. 82-88. DOI: 10.1016/j.pbi.2018.02.001
Monsion, B, Incarbone, M, Hleibieh, K, Poignavent, V, Ghannam, A, Dunoyer, P, Daeffler, L, Tilsner, J & Ritzenthaler, C 2018, 'Efficient detection of long dsRNA in vitro and in vivo using the dsRNA binding domain from FHV B2 protein' Frontiers in Plant Science, vol. 9, 70. DOI: 10.3389/fpls.2018.00070
生命科学学院
2018年9月4日
