Transcript modification: A potential nutrient-conserving strategy for polyploid plants

Due to greater cell and nucleic acid nutrient requirements, polyploids have been hypothesized to be more constrained than related diploids in terms of cell synthesis and biomass accumulation when soil nutrients are limited.

Here, we grew autotetraploid and diploid Solidago gigantea plants in soils enriched or limited with nitrogen- and phosphorus-(NP) and examined the expression patterns and nutrient composition of transcripts associated with different plant functions to assess whether transcriptome modification altered nutrient constraint patterns of polyploids.

Relative to diploids and independently of soil nutrient treatment, autotetraploids upregulated transcripts associated with reproduction, growth, and development, but downregulated transcripts associated with photosynthesis. However, the differential expression of transcripts associated with environmentally responsive processes, including abiotic and biotic responses and tolerances, depended upon soil nutrient treatment. Specifically, compared to diploids, autotetraploids downregulated these transcripts when grown in NP-limited soils but upregulated them when grown in NP-enriched soils. We also found that relative nutrient usage in transcripts associated with environmental responses compared to core cellular processes was lower for autotetraploids than for diploids in NP-limited but not NP-enriched soils. Furthermore, relative nutrient usage in environmentally responsive transcripts decreased in autotetraploids, but did not differ among diploids grown in NP-limited and NP-enriched soils.

These findings suggest that transcript regulation might minimize polyploid nutrient constraints under limited nutrient availability by reducing expression and nutrient usage in environmentally responsive processes while maintaining nutrient usage in core cellular functions.