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Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production.

Wang X, Wang D, Sun Y, Yang Q, Chang L, Wang L, Meng X, Huang Q, Jin X, Tong Z - Sci Rep (2015)

Bottom Line: Moreover, we found that ethylene improves the generation of small rubber particles.Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented.Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Biology and Genetic Resources for Tropical Crops, Institute of Tropical Biosciences and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou Hainan 571101, China.

ABSTRACT
Ethylene is a stimulant to increase natural rubber latex. After ethylene application, both fresh yield and dry matter of latex are substantially improved. Moreover, we found that ethylene improves the generation of small rubber particles. However, most genes involved in rubber biosynthesis are inhibited by exogenous ethylene. Therefore, we conducted a proteomics analysis of ethylene-stimulated rubber latex, and identified 287 abundant proteins as well as 143 ethylene responsive latex proteins (ERLPs) with mass spectrometry from the 2-DE and DIGE gels, respectively. In addition, more than 1,600 proteins, including 404 ERLPs, were identified by iTRAQ. Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented. Some enzymes for rubber particle aggregation were inhibited to prolong latex flow, and thus finally improved latex production. Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues. This post-translational modification and isoform-specific phosphorylation might be important for ethylene-stimulated latex production. These results not only deepen our understanding of the rubber latex proteome but also provide new insights into the use of ethylene to stimulate rubber latex production.

No MeSH data available.


Related in: MedlinePlus

iTRAQ analysis of rubber latex proteins upon ethylene treatment.Peptides from D3, E3, D5 and E5 latex proteins were labeled with iTRAQ labeling reagents with molecular masses of 115, 117, 114 and 116 Da, respectively. The log10 p-value in the volcano plot for the ratios of 117:115 (E3/D3, left side) and 116:114 (E5/D5, right side) are demonstrated (a). Red spots, proteins significantly (fold change > 1.5, P < 0.05) induced in ethylene treated samples; green spots, proteins significantly reduced in ethylene treated samples. The typical peptide intensity of the four labeling reagents in I-23 is also highlighted (b). Then, false discovery rates for the ranked proteins (c) and reported protein confidence (d) at both the local and global levels are determined. The values of cumulative reverse for the ranked spectra are shown (e). Finally, the statistics describing proteins, peptides and spectra with 99% and 95% confidence are presented as the mean ± SD (f). Abbreviations: FDR, false discovery rate; CVs, confidence values.
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f4: iTRAQ analysis of rubber latex proteins upon ethylene treatment.Peptides from D3, E3, D5 and E5 latex proteins were labeled with iTRAQ labeling reagents with molecular masses of 115, 117, 114 and 116 Da, respectively. The log10 p-value in the volcano plot for the ratios of 117:115 (E3/D3, left side) and 116:114 (E5/D5, right side) are demonstrated (a). Red spots, proteins significantly (fold change > 1.5, P < 0.05) induced in ethylene treated samples; green spots, proteins significantly reduced in ethylene treated samples. The typical peptide intensity of the four labeling reagents in I-23 is also highlighted (b). Then, false discovery rates for the ranked proteins (c) and reported protein confidence (d) at both the local and global levels are determined. The values of cumulative reverse for the ranked spectra are shown (e). Finally, the statistics describing proteins, peptides and spectra with 99% and 95% confidence are presented as the mean ± SD (f). Abbreviations: FDR, false discovery rate; CVs, confidence values.

Mentions: Furthermore, iTRAQ was performed to detect additional ERLPs. The volcano plot p-values for the changed patterns of all identified proteins with 95% peptides >2 upon ethylene stimulation (Fig. 4a), the typical peptide of the protein I-23 (Fig. 4b), the false discovery rates for the ranked proteins (Fig. 4c) and reported protein confidence (Fig. 4d) at both the local and global levels, the cumulative reverse values for the ranked spectra (Fig. 4e), and the statistical values of proteins, peptides and spectra (Fig. 4f) are presented in Fig. 4. Finally, 1,596 ± 50 unique proteins (termed as protein I1-I1621) were identified from 14,977 distinct peptide sequences with 95% confidence (score higher than 1.3; error factor <2). Among them, 1,330 ± 45 proteins were identified with 99% confidence (Fig. 4f; Fig. S4; Table S3). Similar to the results obtained by 2-DE, REF was the most abundant protein with 553 matched peptides, followed by SRPP and hevamine. Abundant proteins, including glucanase, Hev b7.02, HEV1.2, elicitor-responsive protein, Hev b5, pro-hevein, ACAT and enolase, were identified by iTRAQ. Although many abundant proteins [e.g., REF (I1), SRPP (I4), and hevamine (I6)] showed no significant changes in general, some of their family members or protein isoforms (e.g., I63, I357 and I1207 for REF; I39 for SRPP) changed substantially upon ethylene treatment (Fig. S4), consistent with our observation in DIGE gels (Fig. 3).


Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production.

Wang X, Wang D, Sun Y, Yang Q, Chang L, Wang L, Meng X, Huang Q, Jin X, Tong Z - Sci Rep (2015)

iTRAQ analysis of rubber latex proteins upon ethylene treatment.Peptides from D3, E3, D5 and E5 latex proteins were labeled with iTRAQ labeling reagents with molecular masses of 115, 117, 114 and 116 Da, respectively. The log10 p-value in the volcano plot for the ratios of 117:115 (E3/D3, left side) and 116:114 (E5/D5, right side) are demonstrated (a). Red spots, proteins significantly (fold change > 1.5, P < 0.05) induced in ethylene treated samples; green spots, proteins significantly reduced in ethylene treated samples. The typical peptide intensity of the four labeling reagents in I-23 is also highlighted (b). Then, false discovery rates for the ranked proteins (c) and reported protein confidence (d) at both the local and global levels are determined. The values of cumulative reverse for the ranked spectra are shown (e). Finally, the statistics describing proteins, peptides and spectra with 99% and 95% confidence are presented as the mean ± SD (f). Abbreviations: FDR, false discovery rate; CVs, confidence values.
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Related In: Results  -  Collection

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Show All Figures
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f4: iTRAQ analysis of rubber latex proteins upon ethylene treatment.Peptides from D3, E3, D5 and E5 latex proteins were labeled with iTRAQ labeling reagents with molecular masses of 115, 117, 114 and 116 Da, respectively. The log10 p-value in the volcano plot for the ratios of 117:115 (E3/D3, left side) and 116:114 (E5/D5, right side) are demonstrated (a). Red spots, proteins significantly (fold change > 1.5, P < 0.05) induced in ethylene treated samples; green spots, proteins significantly reduced in ethylene treated samples. The typical peptide intensity of the four labeling reagents in I-23 is also highlighted (b). Then, false discovery rates for the ranked proteins (c) and reported protein confidence (d) at both the local and global levels are determined. The values of cumulative reverse for the ranked spectra are shown (e). Finally, the statistics describing proteins, peptides and spectra with 99% and 95% confidence are presented as the mean ± SD (f). Abbreviations: FDR, false discovery rate; CVs, confidence values.
Mentions: Furthermore, iTRAQ was performed to detect additional ERLPs. The volcano plot p-values for the changed patterns of all identified proteins with 95% peptides >2 upon ethylene stimulation (Fig. 4a), the typical peptide of the protein I-23 (Fig. 4b), the false discovery rates for the ranked proteins (Fig. 4c) and reported protein confidence (Fig. 4d) at both the local and global levels, the cumulative reverse values for the ranked spectra (Fig. 4e), and the statistical values of proteins, peptides and spectra (Fig. 4f) are presented in Fig. 4. Finally, 1,596 ± 50 unique proteins (termed as protein I1-I1621) were identified from 14,977 distinct peptide sequences with 95% confidence (score higher than 1.3; error factor <2). Among them, 1,330 ± 45 proteins were identified with 99% confidence (Fig. 4f; Fig. S4; Table S3). Similar to the results obtained by 2-DE, REF was the most abundant protein with 553 matched peptides, followed by SRPP and hevamine. Abundant proteins, including glucanase, Hev b7.02, HEV1.2, elicitor-responsive protein, Hev b5, pro-hevein, ACAT and enolase, were identified by iTRAQ. Although many abundant proteins [e.g., REF (I1), SRPP (I4), and hevamine (I6)] showed no significant changes in general, some of their family members or protein isoforms (e.g., I63, I357 and I1207 for REF; I39 for SRPP) changed substantially upon ethylene treatment (Fig. S4), consistent with our observation in DIGE gels (Fig. 3).

Bottom Line: Moreover, we found that ethylene improves the generation of small rubber particles.Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented.Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Biology and Genetic Resources for Tropical Crops, Institute of Tropical Biosciences and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou Hainan 571101, China.

ABSTRACT
Ethylene is a stimulant to increase natural rubber latex. After ethylene application, both fresh yield and dry matter of latex are substantially improved. Moreover, we found that ethylene improves the generation of small rubber particles. However, most genes involved in rubber biosynthesis are inhibited by exogenous ethylene. Therefore, we conducted a proteomics analysis of ethylene-stimulated rubber latex, and identified 287 abundant proteins as well as 143 ethylene responsive latex proteins (ERLPs) with mass spectrometry from the 2-DE and DIGE gels, respectively. In addition, more than 1,600 proteins, including 404 ERLPs, were identified by iTRAQ. Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented. Some enzymes for rubber particle aggregation were inhibited to prolong latex flow, and thus finally improved latex production. Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues. This post-translational modification and isoform-specific phosphorylation might be important for ethylene-stimulated latex production. These results not only deepen our understanding of the rubber latex proteome but also provide new insights into the use of ethylene to stimulate rubber latex production.

No MeSH data available.


Related in: MedlinePlus