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The conservative cysteines in transmembrane domain of AtVKOR/LTO1 are critical for photosynthetic growth and photosystem II activity in Arabidopsis.

Du JJ, Zhan CY, Lu Y, Cui HR, Wang XY - Front Plant Sci (2015)

Bottom Line: Consistently, the maximum and actual efficiency of photosystem II (PSII) in double-cysteine mutation plants decreased significantly to the level similar to that of the vkor mutant line both under normal growth light and high light.A significantly decreased amount of D1 protein and increased accumulation of reactive oxygen species were observed in two double-cysteine mutations under high light.All of the results above indicated that the conservative cysteines in transmembrane domains were the functional sites of AtVKOR in Arabidopsis and that the oxidoreductase activities of AtVKOR were directly related to the autotrophic photosynthetic growth and PSII activity of Arabidopsis thaliana.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University Tai´an, China.

ABSTRACT
Thylakoid protein vitamin K epoxide reductase (AtVKOR/LTO1) is involved in oxidoreduction. The deficiency of this compound causes pleiotropic defects in Arabidopsis thaliana, such as severely stunted growth, smaller sized leaves, and delay of flowering. Transgenic complementation of wild-type AtVKOR (VKORWT) to vkor mutant lines ultimately demonstrates that the phenotype changes are due to this gene. However, whether AtVKOR functions in Arabidopsis through its protein oxidoreduction is unknown. To further study the redox-active sites of AtVKOR in vivo, a series of plasmids containing cysteine-mutant VKORs were constructed and transformed into vkor deficient lines. Compared with transgenic AtVKORWT plants, the size of the transgenic plants with a single conservative cysteine mutation (VKORC109A, VKORC116A, VKORC195A, and VKORC198A) were smaller, and two double-cysteine mutations (VKORC109AC116A and VKORC195AC198A) showed significantly stunted growth, similar with the vkor mutant line. However, mutations of two non-conservative cysteines (VKORC46A and VKORC230A) displayed little obvious changes in the phenotypes of Arabidopsis. Consistently, the maximum and actual efficiency of photosystem II (PSII) in double-cysteine mutation plants decreased significantly to the level similar to that of the vkor mutant line both under normal growth light and high light. A significantly decreased amount of D1 protein and increased accumulation of reactive oxygen species were observed in two double-cysteine mutations under high light. All of the results above indicated that the conservative cysteines in transmembrane domains were the functional sites of AtVKOR in Arabidopsis and that the oxidoreductase activities of AtVKOR were directly related to the autotrophic photosynthetic growth and PSII activity of Arabidopsis thaliana.

No MeSH data available.


Related in: MedlinePlus

The biomass of cysteine-mutant AtVKORs plants. The fresh weights (FW) of up-ground parts of WT, vkor mutant, AtVKORWT, and cysteine-mutant VKORs plants were measured. The experiments were repeated at least three times and more than three plants were used each time. The error bars indicated the SD. Significant differences are determined using one-way ANOVA and Ducan’s Multiple Range Test, as indicated with different letters at P < 0.05 significance level.
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Figure 2: The biomass of cysteine-mutant AtVKORs plants. The fresh weights (FW) of up-ground parts of WT, vkor mutant, AtVKORWT, and cysteine-mutant VKORs plants were measured. The experiments were repeated at least three times and more than three plants were used each time. The error bars indicated the SD. Significant differences are determined using one-way ANOVA and Ducan’s Multiple Range Test, as indicated with different letters at P < 0.05 significance level.

Mentions: The changes of biomass were further detected in the transgenic plants. The fresh weight (FW) of transgenic plants with double-cysteine mutations (AtVKORC109AC116A and AtVKORC195AC198A) decreased significantly, only about 30% of that of WT and a little more than that of vkor deficient lines (Figure 2). As to transgenic plants with the non-conservative cysteine mutations (AtVKORC46A and AtVKORC230A), the FW decreased a little, about 95% of that of WTs (Figure 2). The changes of biomass were consistent with the phenotypes observed above, further confirming indispensability of the conservative cysteines of AtVKOR in photosynthetic growth of plants.


The conservative cysteines in transmembrane domain of AtVKOR/LTO1 are critical for photosynthetic growth and photosystem II activity in Arabidopsis.

Du JJ, Zhan CY, Lu Y, Cui HR, Wang XY - Front Plant Sci (2015)

The biomass of cysteine-mutant AtVKORs plants. The fresh weights (FW) of up-ground parts of WT, vkor mutant, AtVKORWT, and cysteine-mutant VKORs plants were measured. The experiments were repeated at least three times and more than three plants were used each time. The error bars indicated the SD. Significant differences are determined using one-way ANOVA and Ducan’s Multiple Range Test, as indicated with different letters at P < 0.05 significance level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400859&req=5

Figure 2: The biomass of cysteine-mutant AtVKORs plants. The fresh weights (FW) of up-ground parts of WT, vkor mutant, AtVKORWT, and cysteine-mutant VKORs plants were measured. The experiments were repeated at least three times and more than three plants were used each time. The error bars indicated the SD. Significant differences are determined using one-way ANOVA and Ducan’s Multiple Range Test, as indicated with different letters at P < 0.05 significance level.
Mentions: The changes of biomass were further detected in the transgenic plants. The fresh weight (FW) of transgenic plants with double-cysteine mutations (AtVKORC109AC116A and AtVKORC195AC198A) decreased significantly, only about 30% of that of WT and a little more than that of vkor deficient lines (Figure 2). As to transgenic plants with the non-conservative cysteine mutations (AtVKORC46A and AtVKORC230A), the FW decreased a little, about 95% of that of WTs (Figure 2). The changes of biomass were consistent with the phenotypes observed above, further confirming indispensability of the conservative cysteines of AtVKOR in photosynthetic growth of plants.

Bottom Line: Consistently, the maximum and actual efficiency of photosystem II (PSII) in double-cysteine mutation plants decreased significantly to the level similar to that of the vkor mutant line both under normal growth light and high light.A significantly decreased amount of D1 protein and increased accumulation of reactive oxygen species were observed in two double-cysteine mutations under high light.All of the results above indicated that the conservative cysteines in transmembrane domains were the functional sites of AtVKOR in Arabidopsis and that the oxidoreductase activities of AtVKOR were directly related to the autotrophic photosynthetic growth and PSII activity of Arabidopsis thaliana.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University Tai´an, China.

ABSTRACT
Thylakoid protein vitamin K epoxide reductase (AtVKOR/LTO1) is involved in oxidoreduction. The deficiency of this compound causes pleiotropic defects in Arabidopsis thaliana, such as severely stunted growth, smaller sized leaves, and delay of flowering. Transgenic complementation of wild-type AtVKOR (VKORWT) to vkor mutant lines ultimately demonstrates that the phenotype changes are due to this gene. However, whether AtVKOR functions in Arabidopsis through its protein oxidoreduction is unknown. To further study the redox-active sites of AtVKOR in vivo, a series of plasmids containing cysteine-mutant VKORs were constructed and transformed into vkor deficient lines. Compared with transgenic AtVKORWT plants, the size of the transgenic plants with a single conservative cysteine mutation (VKORC109A, VKORC116A, VKORC195A, and VKORC198A) were smaller, and two double-cysteine mutations (VKORC109AC116A and VKORC195AC198A) showed significantly stunted growth, similar with the vkor mutant line. However, mutations of two non-conservative cysteines (VKORC46A and VKORC230A) displayed little obvious changes in the phenotypes of Arabidopsis. Consistently, the maximum and actual efficiency of photosystem II (PSII) in double-cysteine mutation plants decreased significantly to the level similar to that of the vkor mutant line both under normal growth light and high light. A significantly decreased amount of D1 protein and increased accumulation of reactive oxygen species were observed in two double-cysteine mutations under high light. All of the results above indicated that the conservative cysteines in transmembrane domains were the functional sites of AtVKOR in Arabidopsis and that the oxidoreductase activities of AtVKOR were directly related to the autotrophic photosynthetic growth and PSII activity of Arabidopsis thaliana.

No MeSH data available.


Related in: MedlinePlus