Correlations among genetic, epigenetic, and phenotypic variation of Phragmites australis along latitudes

Aim

Estuarine vegetation routinely experiences natural tidal fluctuations and is highly vulnerable to extreme events such as heavy rainfall, leading to changes in plant population structure and adaptability. Genetic and epigenetic modifications are widely considered to be mechanisms of phenotypic variation, triggered in plants responding to extreme changing environments. However, understanding on correlations among genetic, epigenetic, and phenotypic variation of wild plant populations is still limited.

Location

China.

Methods

In this study, populations of the typical wetland clonal species Phragmites australis were selected from four estuaries along various latitudes in China. Genetic and epigenetic diversity and phenotypic variation of these populations were analysed.

Results

Phenotypic variation of P. australis populations was the highest at Yellow River Estuary and the lowest at Min River Estuary. Across all estuaries, Genetic and epigenetic diversity was strongly linear-correlated. Genetic diversity had significant correlations with variation in reproductive traits, whereas epigenetic diversity had significant correlations with variation in growth traits. Climatic factors of mean annual temperature and precipitation, as well as soil nitrogen and phosphorus, were negatively correlated with variation in genetic diversity, epigenetic diversity, and variation in reproductive traits of P. australis populations along latitudes. Variation in growth traits was negatively correlated with soil salinity, reflecting the limiting effect of salinity on plant growth.

Main Conclusion

Our findings found that genetic and epigenetic variations may play different roles in phenotypic variation of P. australis populations along latitudes, the variation becomes greater when the climatic and edaphic conditions deteriorate. The findings shed new light on the adaptation and evolution of wetland plant populations along a large latitudinal scale, and may contribute to the revegetation of estuary wetlands.