Whole genome duplication enhances the photosynthetic capacity of Chrysanthemum nankingense.

Whole genome duplication has a major effect on the phenotype and physiology of higher plants. A comparison between the diploid and tetraploid forms of Chrysanthemum nankingense showed that the latter's leaf contained a higher content of chlorophyll a/b and harbored a larger number of chloroplasts per cell, leading to an enhancement in its photosynthetic capacity and an improved level of productivity with respect to biomass. A transcriptomic analysis of the two ploidy level forms revealed 21,559 differentially transcribed genes. Compared with diploid progenitor, a number of genes associated with chlorophyll synthesis and those encoding components of photosystems I and II were up-regulated in the tetraploid form, while those associated with chlorophyll degradation were down-regulated. These results indicated that whole genome duplication can directly affect chlorophyll synthesis/degradation and photosynthesis pathways associated with plant growth ratio and biomass accumulation.