The journey of two Agronautes along the plant germline
- Date: Aug 24, 2022
- Time: 02:00 PM - 03:30 PM (Local Time Germany)
- Speaker: Ruben Gutzat
- Gregor Mendel Institute of Molecular Plant Biology GMBH, Autria
- Location: Central Building
- Room: Lecture Hall
- Host: Claudia Köhler
In contrast to most animals, plants are considered to lack an early segregating germline (Lanfear, 2018), implying that somatic cells can contribute genetic information to the progeny. We show that two ARGONAUTE proteins, AGO5 and AGO9, mark an early-segregating germline in the shoot apical meristem (SAM). Analysis of co-precipitated sRNAs revealed that AGO5-bound sRNAs are mainly derived from LTR/Gypsy transposable elements. AGO9-bound sRNAs change from mostly LTR/Gypsy- to Helitron-derived during development. Sequencing single nuclei revealed that many of these transposons are co-expressed within an AGO5/9 expression domain of the SAM.
Lack of AGO5 correlated with a reduction in CHH and CHG methylation at TEs. Interes tingly, AGO5 also binds to miRNAs that can trigger easiRNA biogenesis (Borges et al., 2018), and we identified a majority of ddm1 derepressed transposons as AGO5 cargo in wild type.
Taken together, AGO5 and AGO9 are hallmarks of the Arabidopsis germline, which is established early in plant development, characterized by inflated TE expression and host counter defense, including the easiRNA pathway.