What are the perks of having more ‘genomic currency’ (i.e. larger genome sizes) for plants under rapidly changing environments?
Polyploidy, or whole genome duplication of an organism or cell, exists in all eukaryotes. Not only does polyploidy exist in fungi, insects, fish, amphibians, reptiles, and humans (e.g. cancer cells), but also occurs frequently in plants. Essentially, all flowering plants are ancient polyploids or bear a polyploid ancestry. Around 15% of the speciation events can be linked to polyploidy. For contemporary plant species, around 1/4 to 1/3 are polyploids (i.e. with >2 sets of chromosomes). Thus, polyploidy is considered as one of the most important drivers of plant biodiversity on Earth. Yet, the adaptive importance of polyploidy to environmental change is often implicated but rarely tested.
To address this question, we previously grew diploid and polyploid perennial wild strawberries together in cool coastal, temperate valley, and arid montane regions. We found that polyploids have higher fitness than diploids consistently across the heterogeneous environments. Their fitness can be linked to both leaf functional traits and trait plasticity. We further verified this finding by comparing synthetic polyploid strawberries (with artificially doubled genomes) to diploid strawberries.
While our previous work has elucidated essential ecological mechanisms underlying polyploid success, we yet don’t know the extent to which such polyploid advantage is attributed to plant-associated microbiomes. Thus, our current project aims to address two major questions: (1) Do diploids and polyploids differ in associated microbiomes? (2) How do microbiomes contribute to polyploid advantage in response to environmental change? We address these questions using two diploid–polyploid plant systems: wild strawberries (Fragaria) collected across the globe and the natural populations growing at the Holden Arboretum; and wild apples (crabapples, Malus) at Holden’s National Crabapple Evaluation Project (NCEP) plot. This project involves manipulative experiments, natural and synthetic microbiome inoculation, microbiome sequencing, and plant ecophysiological trait measurements both belowground and aboveground.
crabapple, climate change, NCEP plot, microbiome, physiology, polyploidy, soil, strawberry