Endophytic Pseudomonas fluorescens relieves intraspecies allelopathy in
Atractylodes lancea by reducing ethylene emissions
Abstract
Atractylodes lancea is a perennial herb containing multiple
medicinal ingredients that is currently at risk due to habitat shortages
and improper planting. Its cropping method makes Atractylodes
lancea affected by allelopathy, due to lack of ventilation. Endophytic
bacteria have been reported to be able to increase the growth of hosts
in many species. To promote the yield of Atractylodes lancea
cropping and explore whether intraspecific allelopathy could be relieved
by endophytic bacteria, we designed an airborne signal exchange system
and found that ethylene produced by neighboring plants is a chemical
agent that decreases the root length and dry weight of nearby
Atractylodes lancea, also decreasing the essential oil content at
the same time. Our results showed the endophytic bacterium
Pseudomonas fluorescens (ALEB7B) was able to suppress the
airborne signal of allelopathy by decreasing ethylene emissions. Unlike
cases where pathogen or herbivore enhances plant-plant interactions in
which decrease the growth of nearby plants, treatment with ALEB7B
improves the growth of nearby plants and increases essential oil
production of neighbors. These results were further confirmed by
transcriptome analysis in pot experiments. Our result revealed that
ethylene emitted by Atractylodes lancea has an intraspecific
allelopathic effect that can be relieved by the endophytic bacterium
Pseudomonas fluorescens by decreasing ethylene emission. This
study discovered a new mode how endophytic bacterium promote the growth
and essential accumulation.