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Hyperspectral imaging techniques for rapid identification of Arabidopsis mutants with altered leaf pigment status.

Matsuda O, Tanaka A, Fujita T, Iba K - Plant Cell Physiol. (2012)

Bottom Line: The 'non-targeted' mode highlights differences in reflectance spectra of leaf samples relative to reference spectra from the wild-type leaves.Analysis of these and other mutants revealed that the RI-based targeted pigment estimation was robust at least against changes in trichome density, but was confounded by genetic defects in chloroplast photorelocation 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan. matsuda.osamu.084@m.kyushu-u.ac.jp

ABSTRACT
The spectral reflectance signature of living organisms provides 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 subject of quantitative analysis; its potential for illuminating the pathway leading from the gene to phenotype remains largely unexplored. In this study, we employed hyperspectral imaging 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 reflectance indices (RIs) developed for Chls a and b, carotenoids and anthocyanins. The 'non-targeted' mode highlights differences 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 reflectance phenotypes, that are hardly identifiable by simple observation, were isolated. Analysis of these and other mutants revealed that the RI-based targeted pigment estimation was robust at least against changes in trichome density, but was confounded by genetic defects in chloroplast photorelocation 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.

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Absorption spectra of the major leaf pigments. The spectra are plotted in terms of molar extinction coefficient. Standards of Chls and Anth (cyanidin chloride) were prepared in neutral and acid methanol, respectively. Car (β-carotene) was dissolved in acetone, because of its low solubility and therefore the difficulty in preparing a homogeneous solution in methanol from its dried form. The maxima are adjusted to the values reported by Lichtenthaler (1987).
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pcs043-F1: Absorption spectra of the major leaf pigments. The spectra are plotted in terms of molar extinction coefficient. Standards of Chls and Anth (cyanidin chloride) were prepared in neutral and acid methanol, respectively. Car (β-carotene) was dissolved in acetone, because of its low solubility and therefore the difficulty in preparing a homogeneous solution in methanol from its dried form. The maxima are adjusted to the values reported by Lichtenthaler (1987).

Mentions: To achieve high-accuracy estimation of leaf physiological status based on spectral reflectance measurement, it is of practical interest to investigate reflectance indices (RIs) that help determine individual pigment concentrations. There are, however, several difficulties that need to be resolved in developing pigment-specific RIs. First, we still do not have much knowledge about in situ spectroscopic properties of individual pigments, as their absorption spectra can be influenced by interaction with solvents and other solutes (Lichtenthaler 1987, Porra 2002). Secondly, there is considerable overlap between the absorption spectra of different pigments (Fig. 1), which demands advanced spectral decomposition techniques to estimate the accurate relative contribution of a pigment of interest to the total reflectance. Thirdly, there is naturally a close interrelationship between the concentrations of different pigments (see Supplementary Fig. S1A); a series of leaf samples with diverse pigment compositions are needed to establish the specificity of the RIs. Fourthly, the range of factors other than pigments that influence the reflectance spectra must be taken into consideration; it is particularly important that the measured spectra be adjusted for differences in backscatter between leaf samples.Fig. 1


Hyperspectral imaging techniques for rapid identification of Arabidopsis mutants with altered leaf pigment status.

Matsuda O, Tanaka A, Fujita T, Iba K - Plant Cell Physiol. (2012)

Absorption spectra of the major leaf pigments. The spectra are plotted in terms of molar extinction coefficient. Standards of Chls and Anth (cyanidin chloride) were prepared in neutral and acid methanol, respectively. Car (β-carotene) was dissolved in acetone, because of its low solubility and therefore the difficulty in preparing a homogeneous solution in methanol from its dried form. The maxima are adjusted to the values reported by Lichtenthaler (1987).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3367163&req=5

pcs043-F1: Absorption spectra of the major leaf pigments. The spectra are plotted in terms of molar extinction coefficient. Standards of Chls and Anth (cyanidin chloride) were prepared in neutral and acid methanol, respectively. Car (β-carotene) was dissolved in acetone, because of its low solubility and therefore the difficulty in preparing a homogeneous solution in methanol from its dried form. The maxima are adjusted to the values reported by Lichtenthaler (1987).
Mentions: To achieve high-accuracy estimation of leaf physiological status based on spectral reflectance measurement, it is of practical interest to investigate reflectance indices (RIs) that help determine individual pigment concentrations. There are, however, several difficulties that need to be resolved in developing pigment-specific RIs. First, we still do not have much knowledge about in situ spectroscopic properties of individual pigments, as their absorption spectra can be influenced by interaction with solvents and other solutes (Lichtenthaler 1987, Porra 2002). Secondly, there is considerable overlap between the absorption spectra of different pigments (Fig. 1), which demands advanced spectral decomposition techniques to estimate the accurate relative contribution of a pigment of interest to the total reflectance. Thirdly, there is naturally a close interrelationship between the concentrations of different pigments (see Supplementary Fig. S1A); a series of leaf samples with diverse pigment compositions are needed to establish the specificity of the RIs. Fourthly, the range of factors other than pigments that influence the reflectance spectra must be taken into consideration; it is particularly important that the measured spectra be adjusted for differences in backscatter between leaf samples.Fig. 1

Bottom Line: The 'non-targeted' mode highlights differences in reflectance spectra of leaf samples relative to reference spectra from the wild-type leaves.Analysis of these and other mutants revealed that the RI-based targeted pigment estimation was robust at least against changes in trichome density, but was confounded by genetic defects in chloroplast photorelocation 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan. matsuda.osamu.084@m.kyushu-u.ac.jp

ABSTRACT
The spectral reflectance signature of living organisms provides 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 subject of quantitative analysis; its potential for illuminating the pathway leading from the gene to phenotype remains largely unexplored. In this study, we employed hyperspectral imaging 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 reflectance indices (RIs) developed for Chls a and b, carotenoids and anthocyanins. The 'non-targeted' mode highlights differences 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 reflectance phenotypes, that are hardly identifiable by simple observation, were isolated. Analysis of these and other mutants revealed that the RI-based targeted pigment estimation was robust at least against changes in trichome density, but was confounded by genetic defects in chloroplast photorelocation 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.

Show MeSH
Related in: MedlinePlus