Spray-induced gene silencing for the control of liverwort in forest nurseries
Project overview
Short summary
Liverwort is a common problem in forest nurseries, where it competes with tree seedlings and reduces production efficiency. This project investigates an environmentally sustainable alternative using an RNA-based control strategy called spray-induced gene silencing (SIGS).
Liverwort (Marchantia polymorpha), a small plant that can form dense mats on moist soil, is a widespread problem in forest nurseries. These mats compete with young tree seedlings for space, water and nutrients, which can negatively affect seedling growth and nursery production.
Until recently, control strategies in Sweden relied largely on chemical herbicides. However, these are being phased out due to regulatory restrictions and environmental concerns. As a result, forest nurseries now depend mainly on manual removal of liverwort, which is labour-intensive and costly.
This doctoral project aims to develop a new and environmentally sustainable method to control M. polymorpha using spray-induced gene silencing (SIGS), an RNA-based technology that switches off essential genes in the target plant.
The basic principle of SIGS is the application of RNA molecules that are complementary to an essential gene in the weed plant. When these RNA molecules are taken up by the plant, they activate natural gene regulation mechanisms that silence the target gene. This can disrupt vital biological processes and reduce the vitality of the treated plant.
The project begins by investigating the genetic diversity of M. polymorpha populations in Swedish forest nurseries. Genes essential for the growth and development of the liverwort, as well as their small RNA (sRNA) regulators, will be identified through RNA extraction and analysis.
In the main phase of the project, the effectiveness of SIGS for controlling liverwort in forest nurseries will be evaluated. Public genome resources will be used for computer-based analyses to identify suitable target genes and design double-stranded RNA (dsRNA), a type of RNA used to silence specific genes.
Laboratory and greenhouse experiments will then be conducted to optimise dsRNA uptake, stability and gene silencing efficiency in M. polymorpha.
In addition, possible unintended effects on other plants and soil microbial communities will be assessed to ensure that the method can be applied safely and responsibly in forest nursery environments.
Research team
PhD student: Jule Hansen,
Department of Forest Mycology and Plant Pathology
Main supervisor: Malin Elfstrand
Assistant supervisors:
Mukesh Dubey
Magnus Karlsson
Ramesh Vetukuri
Magnus Hertzberg, SweTree Technologies
Collaborating partner: SweTree Technologies
Project period: 2026-01 – 2031-01
This project is part of WIFORCE – the Wallenberg Initiative in Forest Research, funded by the Knut and Alice Wallenberg Foundation.