Quantitative phosphoproteomic profiling of fiber differentiation and initiation in a fiberless mutant of cotton

Abstract

BackgroundThe cotton (Gossypium spp.) fiber cell is an important unicellular model for studying cell differentiation. There is evidence suggesting that phosphorylation is a critical post-translational modification involved in regulation of a wide range of cell activities. Nevertheless, the sites of phosphorylation in G. hirsutum and their regulatory roles in fiber cell initiation are largely unknown. In this study, we employed a mass spectrometry-based phosphoproteomics to conduct a global and site-specific phosphoproteome profiling between ovules of a fuzzless-lintless (fl) Upland cotton (G. hirsutum) mutant and its isogenic parental wild type (WT) at -3 and 0 days post-anthesis (DPA).ResultsA total of 830 phosphopeptides and 1,592 phosphorylation sites from 619 phosphoproteins were identified by iTRAQ (isobaric tags for relative and absolute quantitation). Of these, 76 phosphoproteins and 1,100 phosphorylation sites were identified for the first time after searching the P3DB public database using the BLAST program. Among the detected phosphopeptides, 69 were differentially expressed between the fl mutant and its WT in ovules at -3 and 0 DPA. An analysis using the Motif-X program uncovered 19 phosphorylation motifs, 8 of which were unique to cotton. A further metabolic pathway analysis revealed that the differentially phosphorylated proteins were involved in signal transduction, protein modification, carbohydrate metabolic processes, and cell cycle and cell proliferation.ConclusionsOur phosphoproteomics-based research provides the first global overview of phosphorylation during cotton fiber initiation, and also offers a helpful dataset for elucidation of signaling networks in fiber development of G. hirsutum.Electronic supplementary materialThe online version of this article (doi: 10.1186/1471-2164-15-466) contains supplementary material, which is available to authorized users.

Comparative Phosphoproteomics Reveals an Important Role of MKK2 in Banana (Musa spp.) Cold Signal Network

“…This result is in good agreement with previous report in other plants: 89.3% pSer, 10.2% pThr, and 0.5% pTyr in soybean27 and 89.4% pSer, 9.5% pThr, and 1.1% pTyr in cotton28. However, the result of Dajiao showed a considerable difference.…”

“…S2B and Table S3). Most of the annotated phosphoproteins of Cavendish Banana and Dajiao are involved in binding, cellular process and catalytic activity, consistent with the findings of previous investigation2830.…”

“…The same distribution of 213 (88.4%), 27 (11.2%) and 1 (0.4%), respectively, occurred in Dajiao (Table 1, see Supplementary Table S1). These values are very different from those reported for cotton (33.4%, 48.3%, and 18.3%)28, but are quite consistent with those found in Arabidopsis (80.9%, 19.1%, and 0%)29. This difference is conceivable with the use of different methodologies or biological systems, where different tissue and organism under a particular condition may have a special phosphoproteome profile.…”

Recent advances and challenges in plant phosphoproteomics

“…Quantitation is achieved in MS/MS where the tags are released, and the differences among the tag intensities reflect the original quantities of peptides and proteins in different samples . In phosphoproteomics research, these technologies have been extensively used (Table ). However, isobaric tag labeled peptides showed reduced identification efficiency as much as 50% in multistage activation (MSA) MS/MS due to the high charge state induced by the tag in ESI.…”

Proteomic Profiles of Cotton Fiber Developmental Transition from Cell Elongation to Secondary Wall Deposition

“…Amongst the various proteomic technologies, the "isobaric tags for relative and absolute quantitation" (iTRAQ) method can identify numerous proteins and provide more reliable quantitative information than conventional analysis by two-dimensional gel electrophoresis [4]. Prior studies using iTRAQ analysis have gained insight into the differences in gene/protein expression of cotton in response to environment stress [5], and domestication [6], as well as fiber development [7][8][9].…”