Cornell Chronicle Reports

Our publication on the vertical transmission of symbiotic bacteria in whiteflies is reported in The Cornell Chronicle: Ancient symbiosis points to possible whitefly controls

This work is a collaboration with colleagues at Zhejiang University China (Hong Wei Shan and Shu Sheng Liu) and the Department of Biomedical Engineering at Cornell (Philipp Isermann and Jan Lamerding). For financial support, we thank the Natural Resources Institute, University of Greenwich from a grant provided by the Bill & Melinda Gates foundation, the National Natural Science Foundation of China, and NSF.

Luan JB*, Shan H-W*, Isermann P, Huang J-H, Lammerding J, Liu S-S and Douglas AE 2016. Cellular and molecular remodeling of a host cell for vertical transmission of bacterial symbionts. Proceedings of the Royal Society of London B 283, 1833 [*joint first authors] Pubmed Link

Bemisia VT

The symbiotic bacteria Portiera (green) pack the cytoplasm of the bacteriocyte transferring to the ovary of the insect, here visualized as nuclei (red) of the ovarian follicle. (H-W Shan)

Abstract: Various insects require intracellular bacteria that are restricted to specialized cells (bacteriocytes) and are transmitted vertically via the female ovary, but the transmission mechanisms are obscure. We hypothesized that, in the whitefly Bemisia tabaci where intact bacteriocytes (and not isolated bacteria) are transferred to oocytes, the transmission mechanism would be evident as cellular and molecular differences between the nymph (pre-adult) and adult bacteriocytes. We demonstrate dramatic remodeling of bacteriocytes at the developmental transition from nymph to adulthood. This transition involves the loss of cell-cell adhesion, high division rates to constant cell size and onset of cell mobility, enabling the bacteriocytes to crawl to the ovaries. These changes are accompanied by cytoskeleton reorganization and changes in gene expression: genes functioning in cell-cell adhesion display reduced expression, and genes involved in cell division, cell motility and endocytosis/exocytosis have elevated expression in adult bacteriocytes, relative to nymph bacteriocytes. This study demonstrates, for the first time, how developmentally-orchestrated remodeling of gene expression and correlated changes in cell behavior underpin the capacity of bacteriocytes to mediate the vertical transmission and persistence of the symbiotic bacteria on which the insect host depends.

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