Correlation between phenotype and proteome in the Ni hyperaccumulator Noccaea caerulescens subsp. caerulescens

The metallicolous population Noccaeacaerulescenssubsp. caerulescens (formerly Thlaspi caerulescens) of Monte Prinzera (MP) (Italy) is a well-known example of a hyperaccumulator. MP has a serpentine soil in which concentrations of Ni can be as high as 2500 mg kg−1. The absence of N. caerulescens in the nearby non-ophiolitic soils along with its growth and reproductive traits, make this population an interesting model to study adaptation to extreme environments. Different phenotypes of N. caerulescens were identified in sub-sites differing in their geo-morphology. Differences in morphological and reproductive traits of plants were found through multivariate statistical analysis and were correlated with soil parameters, such as pH, organic matter content, water and Ni content. Phenotypic variability was correlated at the molecular level with proteome variation. Transcriptional regulators and signal transduction factors were differentially abundant in the sub-populations. We hypothesise that these proteomic variations may be relevant for adaptation of N. caerulescens to specific micro-habitats, at the same time revealing a general trade-off between plants and environment in terms of costs and benefits.