Pegah was just awarded a Mobility Fellowship from the University of Vienna! This fellowship will enable Pegah to visit the “leech lab” at Kyoto University (Japan) led by Dr. Takafumi Nakano. During her visit she aims to gain insight into the microbial symbioses of three Japanese leeches: Hirudo nipponia, Placobdella okai, and Torix tagoi. Through her stay, we also aim to establish a formal collaboration between out two groups and gain important data for planning joint projects on the symbioses present in these organisms.
Thanks to the European Reference Genome Atlas initiative (ERGA) and their Biodiversity Genomics Europe project (BGE), a reference genome for the historical European southern medicinal leech Hirudo verbana Carena, 1820 has been sequenced and assembled to chromosome level!
This specific leech was collected in Vienna, where it should not naturally occur, likely representing an historical introduction into an artificial pond. This so-called “medicinal” leech was erroneously treated for a long time as a colouration type/form H. medicinalis L. 1758, but now is one of several recognised European species (along with H. troctina and H. orientalis). Historically, it has been, and still is, widely used and trafficked for medicinal and pseudo-medicinal purposes. This reference genome will be of great value to different lines of research including
the study of genomic evolution in the Hirudo genus
unravelling cryptic diversity within the morphospecies H. verbana
the exploration of novel putative anticoagulants
the establishment, maintenance, and cross-talk between the leech host and its symbionts.
This January I had the pleasure of visiting the LIIGH – UNAM, at my home city of Querétaro (México), where I was able to talk about the symbiosis research I have done throughout the years and that we now do in the group. I was very impressed with the facilities, students, and the general vibe at the institute. Certainly not the last time I will pay them a visit!
Last week, Pegah Kalatehjari joined the team! Pegah joins us from Iran, with a background in aquaculture, leech biology and reproduction. She will work on the SymBirth project studying symbiont transmission in Placobdella leeches and beyond.
ESEB 2025 just wrapped up last week. It was a great week of talks, posters, and informal chats about all things evolution. Particularly, it was great to catch up with old friends working at the intersection of symbiosis and evolution. Had a great time talking about our recent work on leeches and their symbionts, and of course, aphids too. Looking forward to next ESEB meeting!
Taking advantage of the trip to China for SMBE 2025, Alejandro visited the group of Jun-Bo Luan (https://www.junboluanlab.com/) at the Shenyang Agricultural University (沈阳农业大学). It was a great visit full of insect symbiosis science, cultural visits, culinary experiences, and a great set of people!
Along with Jun-Bo Luan (https://www.junboluanlab.com/), we organised the Symbiosis symposium at SMBE 2025 (Beijing, China). We were thrilled to see the turnout and the great talks covering bioluminiscent symbiosis in Flashlight fish (Chang Liu), microbiome responses to global warming through meta-analyses (Jingdi Li), Honey bee immune system and their gut microbiome (Shiqi Luo), genomic factors of cytoplasmatic incompatibility in Wolbachia (Yongjun Tan), Arctic sponge species’ microbiomes (Anastasiia Rusanova), evolutionary forces driving Blattabacterium‘s convergent gene losses (Zhuli Cheng), multi-omics of the chemosymbiotic Alviniconcha snails (Hui Wang), and the co-evolution of host and gut bacteria during Honey bee acclimation (Min Tang).
In collaboration with Anouk Willemsen (Uniersity of Vienna), we sequenced high-quality genomes of protists known as hosts of giant viruses (GVs). Matching of codon usage preferences is often used to predict virus-host pairs. Our analyses revealed that in GVs, codon usage alone is a poor predictor of known pairs. Why? well, GVs have complex genomes… They encode few to complete tRNA sets and even genes from the translational machinery (e.g. tRNA–ligases). The host immune system may also play a role, driving viral codon usage away from its own. Moreover, its replication site (nuclear vs. cytoplasmatic) could also play a role. Finally, by analyzing the new amoebal genomes, we discovered viral integrations (potentially from GVs) into some of them, indicating historical infections. Most notably some inserted major capsid proteins seem to potentially encode for intact proteins (work in progress)…
Very happy the first group project SymBirth: Development of an artificial symbiont’s birth has been funded by the FWF’s 1000 ideas program. This program aims to fund “[…] completely new, high-risk, or particularly original research ideas that go beyond our current scientific understanding. The focus is on seed funding for forward-looking topics that have high transformative potential for science and research.”
Placobdella costata
In this project, we will study symbiont transmission in the European turtle leech Placobdella costata and related leeches. Using what we learn about this unknown process, we will undertake our ultimate goal of triggering a symbiont replacement event in this species. If accomplished, this project will result in the development of a highly promising model system for the study of the triggering of an obligate symbiotic lifestyle in bacteria.
After many years in the making (and an eternal cycle of adding new data….) our work on the discordance among phylogenomic datasets in is out!
Relationships between subfamilies remain contentious in both mitochondrial and nuclear phylogenies. Topologies obtained with Buchnera appear fully resolved but exhibit some discordance with host phylogenies at deep evolutionary scales and conflict with views on the evolution of aphid morphology. BUT…. further sampling (we had to stop at some point for this study) and sequence-independent analyses, such as male morphology and chromosomal structure, might help piece out some difficult-to-solve/contentious relationships.
Biology and Evolution of Symbiosis (BESymb)
