An Australian tree now bears the evocative nickname "zombie." This term describes the peculiar fate of Rhodamnia zombi, a recently named species, which persists biologically but has lost its ability to flower and fruit.
This tree was identified in the tropical rainforests of Queensland. The
University of Queensland team chose this name to reflect its worrying situation, surviving without being able to reproduce, like a plant-based undead.
A fruit of the Rhodamnia zombi tree, a species threatened by myrtle rust.
Credit: University of Queensland
The cause of this condition is myrtle rust. This fungus systematically targets the young shoots of Rhodamnia zombi. Having appeared in Australia in 2010, this disease blocks the tree's growth and seed formation, leading it towards a gradual disappearance in the absence of measures. Infected specimens are thus left in a state of total sterility. The newly discovered tree species is particularly susceptible to this fungus.
This species is now among 17 plants potentially classified as critically endangered due to myrtle rust. With no natural resistance observed in wild populations, their short-term survival raises concerns, with a risk of extinction within a single generation.
A rescue operation is underway. Scientists are collecting healthy cuttings from the wild before they become contaminated. These cuttings are then cultivated in secure sites, such as in Lismore and Townsville, where young plants are showing encouraging signs. The goal is to get them to produce seeds, in the hope that some of them will show tolerance to the fungus.
Flowers of Rhodamnia zombi before the infection stopped all new growth.
Credit: The University of Queensland
The research, published in
Austral Ecology, explores this avenue. By examining the genome of species closely related to Rhodamnia zombi that show some resistance, botanists are seeking to identify protective genetic characteristics. This approach could eventually allow for the reintroduction of more robust individuals into their native environment.
This also allows for the observation of an evolutionary process in real time. Although ambitious, this initiative gives the species a chance to develop resistance away from the excessive pressure of the disease.