Hyperspectral imaging techniques for rapid identification of arabidopsis mutants with altered leaf pigment status. Plant Cell Physiol

The spectral reflectance signature of living organisms pro-vides information that closely reflects their physiological status. Because of its high potential for the estimation of geomorphic biological parameters, particularly of gross photosynthesis of plants, two-dimensional spectroscopy, via the use of hyperspectral instruments, has been widely used in remote sensing applications. In genetics research, in contrast, the reflectance phenotype has rarely been the sub-ject of quantitative analysis; its potential for illuminating the pathway leading from the gene to phenotype remains largely unexplored. In this study, we employed hyperspectral ima-ging techniques to identify Arabidopsis mutants with altered leaf pigment status. The techniques are comprised of two modes; the first is referred to as the ‘targeted mode’ and the second as the ‘non-targeted mode’. The ‘targeted’ mode is aimed at visualizing individual concentrations and compositional parameters of leaf pigments based on reflect-ance indices (RIs) developed for Chls a and b, carotenoids and anthocyanins. The ‘non-targeted ’ mode highlights dif-ferences in reflectance spectra of leaf samples relative to reference spectra from the wild-type leaves. Through the latter approach, three mutant lines with weak irregular re-flectance phenotypes, that are hardly identifiable by simple observation, were isolated. Analysis of these and other mu-tants revealed that the RI-based targeted pigment estima-tion was robust at least against changes in trichome density, but was confounded by genetic defects in chloroplast photo-relocation movement. Notwithstanding such a limitation, the techniques presented here provide rapid and high-sensitive means to identify genetic mechanisms that coordinate leaf pigment status with developmental stages and/or environmental stress conditions