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The cold responsive mechanism of the paper mulberry: decreased photosynthesis capacity and increased starch accumulation.

Peng X, Teng L, Yan X, Zhao M, Shen S - BMC Genomics (2015)

Bottom Line: Finally, real time PCR was used to verify the DEG results of the RNA-seq and the proteomics data.Results showed that at the beginning of cold stress, respiratory metabolism was decreased and the transportation and hydrolysis of photosynthetic products was inhibited, leading to an accumulation of starch in the chloroplasts.Most of important, enhancing the transport and hydrolysis of photosynthetic products could be the potential targets for improving the cold tolerance of the paper mulberry.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China. pengxianjun@ibcas.ac.cn.

ABSTRACT

Background: Most studies on the paper mulberry are mainly focused on the medicated and pharmacology, fiber quality, leaves feed development, little is known about its mechanism of adaptability to abiotic stress. Physiological measurement, transcriptomics and proteomic analysis were employed to understand its response to cold stress in this study.

Methods: The second to fourth fully expanded leaves from up to down were harvested at different stress time points forthe transmission electron microscope (TEM) observation. Physiological characteristics measurement included the relative electrolyte leakage (REL), SOD activity assay, soluble sugar content, and Chlorophyll fluorescence parameter measurement. For screening of differentially expressed genes, the expression level of every transcript in each sample was calculated by quantifying the number of Illumina reads. To identify the differentially expressed protein, leaves of plants under 0, 6, 12, 24, 48 and 72 h cold stress wereharvested for proteomic analysis. Finally, real time PCR was used to verify the DEG results of the RNA-seq and the proteomics data.

Results: Results showed that at the beginning of cold stress, respiratory metabolism was decreased and the transportation and hydrolysis of photosynthetic products was inhibited, leading to an accumulation of starch in the chloroplasts. Total of 5800 unigenes and 38 proteins were affected, including the repressed expression of photosynthesis and the enhanced expression in signal transduction, stress defense pathway as well as secondary metabolism. Although the transcriptional level of a large number of genes has been restored after 12 h, sustained cold stress brought more serious injury to the leaf cells, including the sharp rise of the relative electrolyte leakage, the declined Fv/Fm value, swelled chloroplast and the disintegrated membrane system.

Conclusion: The starch accumulation and the photoinhibition might be the main adaptive mechanism of the paper mulberry responded to cold stress. Most of important, enhancing the transport and hydrolysis of photosynthetic products could be the potential targets for improving the cold tolerance of the paper mulberry.

No MeSH data available.


Related in: MedlinePlus

Changes of four physiological traits in leaves of paper mulberry under cold stress. a REL. b Maximum photochemical efficiency Fv/Fm. c Soluble sugar content. d SOD activity. Values are presented as mean ± SD of three biological replicates. Duncan’s test (p < 0.05) was used for data statistics at different time points and letters a, b, c, d, and e indicated statistical significance
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Fig2: Changes of four physiological traits in leaves of paper mulberry under cold stress. a REL. b Maximum photochemical efficiency Fv/Fm. c Soluble sugar content. d SOD activity. Values are presented as mean ± SD of three biological replicates. Duncan’s test (p < 0.05) was used for data statistics at different time points and letters a, b, c, d, and e indicated statistical significance

Mentions: The damage on plasma membrane could also be detected by measurement of REL (relative electrolyte leakage), an indicator of membrane integrity. Impairment of membrane led to leakage of ions from cytosol through cell membranes. The changes in REL were monitored over 72 h cold stresses (Fig. 2a). Under the normal condition (Clonal plantlets were cultured at 26 °C), the REL of the paper mulberry is 5.4 %. It increased moderately at the first 6 h compared with the control, followed by a slightly decrease up to 24 h. After that, the REL increased drastically to 12.57 % at 48 h, and then reached a maximum of 27.19 % at 72 h after cold stress.Fig. 2


The cold responsive mechanism of the paper mulberry: decreased photosynthesis capacity and increased starch accumulation.

Peng X, Teng L, Yan X, Zhao M, Shen S - BMC Genomics (2015)

Changes of four physiological traits in leaves of paper mulberry under cold stress. a REL. b Maximum photochemical efficiency Fv/Fm. c Soluble sugar content. d SOD activity. Values are presented as mean ± SD of three biological replicates. Duncan’s test (p < 0.05) was used for data statistics at different time points and letters a, b, c, d, and e indicated statistical significance
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4634900&req=5

Fig2: Changes of four physiological traits in leaves of paper mulberry under cold stress. a REL. b Maximum photochemical efficiency Fv/Fm. c Soluble sugar content. d SOD activity. Values are presented as mean ± SD of three biological replicates. Duncan’s test (p < 0.05) was used for data statistics at different time points and letters a, b, c, d, and e indicated statistical significance
Mentions: The damage on plasma membrane could also be detected by measurement of REL (relative electrolyte leakage), an indicator of membrane integrity. Impairment of membrane led to leakage of ions from cytosol through cell membranes. The changes in REL were monitored over 72 h cold stresses (Fig. 2a). Under the normal condition (Clonal plantlets were cultured at 26 °C), the REL of the paper mulberry is 5.4 %. It increased moderately at the first 6 h compared with the control, followed by a slightly decrease up to 24 h. After that, the REL increased drastically to 12.57 % at 48 h, and then reached a maximum of 27.19 % at 72 h after cold stress.Fig. 2

Bottom Line: Finally, real time PCR was used to verify the DEG results of the RNA-seq and the proteomics data.Results showed that at the beginning of cold stress, respiratory metabolism was decreased and the transportation and hydrolysis of photosynthetic products was inhibited, leading to an accumulation of starch in the chloroplasts.Most of important, enhancing the transport and hydrolysis of photosynthetic products could be the potential targets for improving the cold tolerance of the paper mulberry.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China. pengxianjun@ibcas.ac.cn.

ABSTRACT

Background: Most studies on the paper mulberry are mainly focused on the medicated and pharmacology, fiber quality, leaves feed development, little is known about its mechanism of adaptability to abiotic stress. Physiological measurement, transcriptomics and proteomic analysis were employed to understand its response to cold stress in this study.

Methods: The second to fourth fully expanded leaves from up to down were harvested at different stress time points forthe transmission electron microscope (TEM) observation. Physiological characteristics measurement included the relative electrolyte leakage (REL), SOD activity assay, soluble sugar content, and Chlorophyll fluorescence parameter measurement. For screening of differentially expressed genes, the expression level of every transcript in each sample was calculated by quantifying the number of Illumina reads. To identify the differentially expressed protein, leaves of plants under 0, 6, 12, 24, 48 and 72 h cold stress wereharvested for proteomic analysis. Finally, real time PCR was used to verify the DEG results of the RNA-seq and the proteomics data.

Results: Results showed that at the beginning of cold stress, respiratory metabolism was decreased and the transportation and hydrolysis of photosynthetic products was inhibited, leading to an accumulation of starch in the chloroplasts. Total of 5800 unigenes and 38 proteins were affected, including the repressed expression of photosynthesis and the enhanced expression in signal transduction, stress defense pathway as well as secondary metabolism. Although the transcriptional level of a large number of genes has been restored after 12 h, sustained cold stress brought more serious injury to the leaf cells, including the sharp rise of the relative electrolyte leakage, the declined Fv/Fm value, swelled chloroplast and the disintegrated membrane system.

Conclusion: The starch accumulation and the photoinhibition might be the main adaptive mechanism of the paper mulberry responded to cold stress. Most of important, enhancing the transport and hydrolysis of photosynthetic products could be the potential targets for improving the cold tolerance of the paper mulberry.

No MeSH data available.


Related in: MedlinePlus