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The antioxidative defense system is involved in the premature senescence in transgenic tobacco (Nicotiana tabacum NC89).

Liu Y, Wang L, Liu H, Zhao R, Liu B, Fu Q, Zhang Y - Biol. Res. (2016)

Bottom Line: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants.Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage.The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Dai Zong Street, Tai'an, 271018, Shandong, People's Republic of China.

ABSTRACT

Background: α-Farnesene is a volatile sesquiterpene synthesized by the plant mevalonate (MVA) pathway through the action of α-farnesene synthase. The α-farnesene synthase 1 (MdAFS1) gene was isolated from apple peel (var. white winter pearmain), and transformed into tobacco (Nicotiana tabacum NC89). The transgenic plants had faster stem elongation during vegetative growth and earlier flowering than wild type (WT). Our studies focused on the transgenic tobacco phenotype.

Results: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants. Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide radicals (O 2 (·-) ) had higher levels in transgenics compared to controls. Transgenic plants also had enhanced sensitivity to oxidative stress. The transcriptome of 8-week-old plants was studied to detect molecular changes. Differentially expressed unigene analysis showed that ubiquitin-mediated proteolysis, cell growth, and death unigenes were upregulated. Unigenes related to photosynthesis, antioxidant activity, and nitrogen metabolism were downregulated. Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage.

Conclusions: The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.

No MeSH data available.


Related in: MedlinePlus

Measurement of senescence-related physiological parameters in WT and transgenic plants. A Chlorophyll content, B carotenoid content, C soluble protein content, D net photosynthetic rate, E shows water content, and F signifies malondialdehyde (MDA) content. Data are mean ± SE (n = 5, five biological replicates per line). Differentletters indicate statistically significant differences at P ≤ 0.05
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Fig3: Measurement of senescence-related physiological parameters in WT and transgenic plants. A Chlorophyll content, B carotenoid content, C soluble protein content, D net photosynthetic rate, E shows water content, and F signifies malondialdehyde (MDA) content. Data are mean ± SE (n = 5, five biological replicates per line). Differentletters indicate statistically significant differences at P ≤ 0.05

Mentions: Leaf senescence generally accelerates chlorophyll degradation and cell death [33, 34], which occur simultaneously with protein degradation. For these reasons, chlorophyll and soluble protein levels were measured. The T3-1, T3-2 and T3-3 plants showed a decrease in the content of chlorophyll a by 87.1, 83.9 and 78.2 %; chlorophyll b decreased by 93.7, 86.3 and 80.4 %; the total chlorophyll (a + b) content decreased by 88.2, 88.3 and 84 % (Fig. 3A) and carotenoid content decreased by 70.5, 79.2 and 73.9 %, respectively (Fig. 3B). Soluble protein levels decreased significantly, by 53.8, 51.6 and 53.3 % in T3-1, T3-2 and T3-3, respectively (Fig. 3C). Chlorophyll and photosynthesis proteins are important elements in photosynthesis. The value of Pn decreased significantly by 82.7, 81.9 and 84.8 % in three transgenic lines (Fig. 3D). Water content showed a significant reduction (Fig. 3E). Malondialdehyde (MDA) is the decomposition product of membrane lipid peroxidation, and it accumulates in senescent leaves. MDA content increased by 121.7, 127.1 and 119.7 % in the T3-1, T3-2, and T3-3 lines, respectively (Fig. 3F).Fig. 3


The antioxidative defense system is involved in the premature senescence in transgenic tobacco (Nicotiana tabacum NC89).

Liu Y, Wang L, Liu H, Zhao R, Liu B, Fu Q, Zhang Y - Biol. Res. (2016)

Measurement of senescence-related physiological parameters in WT and transgenic plants. A Chlorophyll content, B carotenoid content, C soluble protein content, D net photosynthetic rate, E shows water content, and F signifies malondialdehyde (MDA) content. Data are mean ± SE (n = 5, five biological replicates per line). Differentletters indicate statistically significant differences at P ≤ 0.05
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4930573&req=5

Fig3: Measurement of senescence-related physiological parameters in WT and transgenic plants. A Chlorophyll content, B carotenoid content, C soluble protein content, D net photosynthetic rate, E shows water content, and F signifies malondialdehyde (MDA) content. Data are mean ± SE (n = 5, five biological replicates per line). Differentletters indicate statistically significant differences at P ≤ 0.05
Mentions: Leaf senescence generally accelerates chlorophyll degradation and cell death [33, 34], which occur simultaneously with protein degradation. For these reasons, chlorophyll and soluble protein levels were measured. The T3-1, T3-2 and T3-3 plants showed a decrease in the content of chlorophyll a by 87.1, 83.9 and 78.2 %; chlorophyll b decreased by 93.7, 86.3 and 80.4 %; the total chlorophyll (a + b) content decreased by 88.2, 88.3 and 84 % (Fig. 3A) and carotenoid content decreased by 70.5, 79.2 and 73.9 %, respectively (Fig. 3B). Soluble protein levels decreased significantly, by 53.8, 51.6 and 53.3 % in T3-1, T3-2 and T3-3, respectively (Fig. 3C). Chlorophyll and photosynthesis proteins are important elements in photosynthesis. The value of Pn decreased significantly by 82.7, 81.9 and 84.8 % in three transgenic lines (Fig. 3D). Water content showed a significant reduction (Fig. 3E). Malondialdehyde (MDA) is the decomposition product of membrane lipid peroxidation, and it accumulates in senescent leaves. MDA content increased by 121.7, 127.1 and 119.7 % in the T3-1, T3-2, and T3-3 lines, respectively (Fig. 3F).Fig. 3

Bottom Line: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants.Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage.The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Dai Zong Street, Tai'an, 271018, Shandong, People's Republic of China.

ABSTRACT

Background: α-Farnesene is a volatile sesquiterpene synthesized by the plant mevalonate (MVA) pathway through the action of α-farnesene synthase. The α-farnesene synthase 1 (MdAFS1) gene was isolated from apple peel (var. white winter pearmain), and transformed into tobacco (Nicotiana tabacum NC89). The transgenic plants had faster stem elongation during vegetative growth and earlier flowering than wild type (WT). Our studies focused on the transgenic tobacco phenotype.

Results: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants. Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide radicals (O 2 (·-) ) had higher levels in transgenics compared to controls. Transgenic plants also had enhanced sensitivity to oxidative stress. The transcriptome of 8-week-old plants was studied to detect molecular changes. Differentially expressed unigene analysis showed that ubiquitin-mediated proteolysis, cell growth, and death unigenes were upregulated. Unigenes related to photosynthesis, antioxidant activity, and nitrogen metabolism were downregulated. Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage.

Conclusions: The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.

No MeSH data available.


Related in: MedlinePlus