Variations in chloroplast movement and chlorophyll fluorescence among chloroplast division mutants under light stress

Dutta, Siddhartha; Cruz, Jeffrey A.; Imran, Saif; Chen, Jin; Kramer, David; Osteryoung, Katherine W.

doi:10.1093/jxb/erx203

Cited by 36 publications

(31 citation statements)

References 89 publications

(156 reference statements)

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“…7, 8). An overall absorbance increase contradicts to slow chloroplast motion, involving a spectrally broad Δ A decrease demonstrating a light-avoidance strategy (Deamer et al 1967; Brugnoli and Björkman 1992; Dutta et al 2017). The slow Δ A increase is further spectrally distinctive from chloroplast motion due to the lack of strong peak features in the 400–500 nm region (Fig.…”

Section: Discussionmentioning

confidence: 99%

In vivo photoprotection mechanisms observed from leaf spectral absorbance changes showing VIS–NIR slow-induced conformational pigment bed changes

et al. 2019

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Regulated heat dissipation under excessive light comprises a complexity of mechanisms, whereby the supramolecular light-harvesting pigment–protein complex (LHC) shifts state from light harvesting towards heat dissipation, quenching the excess of photo-induced excitation energy in a non-photochemical way. Based on whole-leaf spectroscopy measuring upward and downward spectral radiance fluxes, we studied spectrally contiguous (hyperspectral) transient time series of absorbance A(λ,t) and passively induced chlorophyll fluorescence F(λ,t) dynamics of intact leaves in the visible and near-infrared wavelengths (VIS–NIR, 400–800 nm) after sudden strong natural-like illumination exposure. Besides light avoidance mechanism, we observed on absorbance signatures, calculated from simultaneous reflectance R(λ,t) and transmittance T(λ,t) measurements as A(λ,t) = 1 − R(λ,t) − T(λ,t), major dynamic events with specific onsets and kinetical behaviour. A consistent well-known fast carotenoid absorbance feature (500–570 nm) appears within the first seconds to minutes, seen from both the reflected (backscattered) and transmitted (forward scattered) radiance differences. Simultaneous fast Chl features are observed, either as an increased or decreased scattering behaviour during quick light adjustment consistent with re-organizations of the membrane. The carotenoid absorbance feature shows up simultaneously with a major F decrease and corresponds to the xanthophyll conversion, as quick response to the proton gradient build-up. After xanthophyll conversion (t = 3 min), a kinetically slower but major and smooth absorbance increase was occasionally observed from the transmitted radiance measurements as wide peaks in the green (~ 550 nm) and the near-infrared (~ 750 nm) wavelengths, involving no further F quenching. Surprisingly, in relation to the response to high light, this broad and consistent VIS–NIR feature indicates a slowly induced absorbance increase with a sigmoid kinetical behaviour. In analogy to sub-leaf-level observations, we suggest that this mechanism can be explained by a structure-induced low-energy-shifted energy redistribution involving both Car and Chl. These findings might pave the way towards a further non-invasive spectral investigation of antenna conformations and their relations with energy quenching at the intact leaf level, which is, in combination with F measurements, of a high importance for assessing plant photosynthesis in vivo and in addition from remote observations.Electronic supplementary materialThe online version of this article (10.1007/s11120-019-00664-3) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

In vivo photoprotection mechanisms observed from leaf spectral absorbance changes showing VIS–NIR slow-induced conformational pigment bed changes

et al. 2019

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“…While the adaptive advantage of chloroplast size variation has not been investigated, experiments with Arabidopsis ftsZ and other chloroplast-division mutants have shown that plants with greatly enlarged chloroplasts exhibit defects in chloroplast movement and impairment of some photosynthetic responses as well as reduced mesophyll conductance, and that somewhat altered responses could also be observed in division mutants with less dramatic phenotypes, including ftsZ2-2 (Jeong et al, 2002;Austin and Webber, 2005;Königer et al, 2008;Dutta et al, 2015Dutta et al, , 2017Weise et al, 2015;Xiong et al, 2017). These results, along with the influence of environmental factors on chloroplast size and number discussed above, suggest that fine-tuning of chloroplast size is important for physiological fitness.…”

Section: Discussionmentioning

confidence: 99%

Allelic Variation in the Chloroplast Division Gene FtsZ2-2 Leads to Natural Variation in Chloroplast Size

et al. 2019

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Chloroplast size varies considerably in nature, but the underlying mechanisms are unknown. By exploiting a near-isogenic line population derived from a cross between the Arabidopsis (Arabidopsis thaliana) accessions Cape Verde Islands (Cvi-1), which has larger chloroplasts, and Landsberg erecta (Ler-0), with smaller chloroplasts, we determined that the large-chloroplast phenotype in Cvi-1 is associated with allelic variation in the gene encoding the chloroplast-division protein FtsZ2-2, a tubulin-related cytoskeletal component of the contractile FtsZ ring inside chloroplasts. Sequencing revealed that the Cvi-1 FtsZ2-2 allele encodes a C-terminally truncated protein lacking a region required for FtsZ2-2 interaction with inner-envelope proteins, and functional complementation experiments in a Columbia-0 ftsZ2-2 null mutant confirmed this allele as causal for the increased chloroplast size in Cvi-1. Comparison of FtsZ2-2 coding sequences in the 1001 Genomes database showed that the Cvi-1 allele is rare and identified additional rare loss-of-function alleles, including a natural null allele, in three other accessions, all of which had enlarged-chloroplast phenotypes. The ratio of nonsynonymous to synonymous substitutions was higher among the FtsZ2-2 genes than among the two other FtsZ family members in Arabidopsis, FtsZ2-1, a close paralog of FtsZ2-2, and the functionally distinct FtsZ1-1, indicating more relaxed constraint on the FtsZ2-2 coding sequence than on those of FtsZ2-1 or FtsZ1-1. Our results establish that allelic variation in FtsZ2-2 contributes to natural variation in chloroplast size in Arabidopsis, and they also demonstrate that natural variation in Arabidopsis can be used to decipher the genetic basis of differences in fundamental cell biological traits, such as organelle size. to K.W.O.) and by the National Science Foundation (grant no.

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“…Intriguingly, there are other drawbacks to having large chloroplasts. It was previously found that plants with larger-than-normal chloroplasts accumulate more photosystem II photodamage, independent of their chloroplast movement impairment (Dutta et al 2017). However, the fad5 mutation does not seem to have any alleviating effect on photosynthetic activity in the crl mutant.…”

Section: Wt Crl Crl Fad5mentioning

confidence: 96%

“…(Arabidopsis thaliana) chloroplast-division mutants that have abnormally large chloroplasts have been around for quite some time, not only because they can be identified relatively easily through screening (Pyke & Leech 1991) and because their spectacular morphology sparks intrigue, but because they have proven useful to this day for studying several important biological phenomena related not just to chloroplast division, but to control of cell size, chloroplast movement and light avoidance, and photosynthesis (Dutta et al 2017). "Giant chloroplast"…”

Section: Arabidopsismentioning

confidence: 99%

More Than Just a FAD(5): Unsaturated Fatty Acids in Chloroplasts Elicit Protective Autoimmunity

Rea

2020

Plant Cell

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Variations in chloroplast movement and chlorophyll fluorescence among chloroplast division mutants under light stress

Abstract: Chloroplast division mutants with enlarged chloroplasts or heterogeneous chloroplast populations differ markedly from the wild type in their photorelocation efficiency and/or photosynthetic capacity under high or fluctuating light intensities.

Cited by 36 publications

References 89 publications

In vivo photoprotection mechanisms observed from leaf spectral absorbance changes showing VIS–NIR slow-induced conformational pigment bed changes

In vivo photoprotection mechanisms observed from leaf spectral absorbance changes showing VIS–NIR slow-induced conformational pigment bed changes

Allelic Variation in the Chloroplast Division Gene FtsZ2-2 Leads to Natural Variation in Chloroplast Size

More Than Just a FAD(5): Unsaturated Fatty Acids in Chloroplasts Elicit Protective Autoimmunity

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