Faith is a fine invention
For gentlemen to see;
But microscopes are prudent
In an emergency!
E. Dickinson, LVI
Cytoplasmic incompatibility in parasitic wasps
Maternally inherited endosymbiont can induced Cytoplasmic Incompatibility (CI), an incompatibility between sperm of infected males and egg of uninfected female, which leads to inviable offspring. This is an effective mechanism to promote the endosymbiont spread in the population of hosts. However, the host may develop resistance mechanism to avoid this sterility. Together with Prof. Dr. Johannes Steidle, from Hohenheim University in Germany, we study Spiroplasma (Mollicutes) induction and resistance to CI in the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae). We were able to show that resistance to CI is a male dependent trait, and currently study the genetic mechanism. Since Spiroplasma can thrive outside of host cell, we were able to cultured it and use this off-host symbiont to further study the mechanism of CI induction.
Vector competence and microbiomes of Culicoides biting midges
Culicoides biting midges are vectors of numerus viral disease agents of Ruminants, mainly Bluetongue virus (BTV). Vector competence of Culcioides species depends on specific interactions between the vector and the virus. One of the factors that affect the internal environment of the vector is its microbial communities. We study the competence of Culicoides imicola and Culicoides oxystoma, the main vector species in Israel, to disseminate various BTV serotypes in relation to their microbiome characteristics.
Ecology of endosymbiotic community in spiders
In collaboration with Dr. Jen Whtie (UK, USA), and Dr. Matt Doremus (UI, USA), we studies how interactions among the five members of the native bacterial community of the spider Mermessus fradeorum shape symbiont abundance, localization, vertical transmission, and host reproductive phenotypes, and how these interactions are affected by environmental temperature.
We found that Wolbachia strain 1 (W1) serves as the primary driver of feminization, a phenotype enhanced by co-infection with W3 and correlated with reduced relative abundances of Rickettsiella and Tisiphia. Experimental evolution over 15 generations demonstrated that both highly penetrant feminization and efficient Rickettsiella-mediated cytoplasmic incompatibility (CI) rescue are stably maintained through maternal transmission, even under relaxed selection pressure. However, these interactions are highly sensitive to thermal stress. Elevated temperatures weakened male CI induction, and reduced Rickettsiella titers, and also triggered a transgenerational decline in feminization by fundamentally reshaping the offspring's symbiont community structure.
Interestingly, while expanding this research to sympatric Israeli Mermessus species, molecular analyses revealed that these invasive populations completely lack the characteristic five-member microbial consortium found in their native North American relatives. This unexpected loss of the bacterial community during invasion and establishment has prompted further comparative population genetic analyses between the two lineages.
Previous project:
The metabolic interactions between ticks and symbiotic bacteria
Ticks (Acari: Ixodida) feed exclusively on blood, and are persistently missing B vitamins and co-factors from their meal. Many species, including those of the genus Rhipicephalus (Ixodidae) harbor Coxiella-like endosymbionts (CLE), which provide their hosts with vital nutrients. We have demonstrated that removal of CLE has negative effects on tick development and reproductive fitness. Additionally, computational evidences suggest that CLE produce excess of l-proline which is transported to the tick cells. Nevertheless, the actual foundation underlying symbiosis maintenance in ticks has not been demonstrated to date.
We now study the effect of nutrient supplementation on aposymbiotic ticks, and characterized the role of l-proline in CLE-Rhipicephalus symbiosis.
