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Open Access Research article

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

Qifeng Ma1, Man Wu2, Wenfeng Pei2, Haijing Li2, Xingli Li2, Jinfa Zhang3, Jiwen Yu2* and Shuxun Yu12*

Author Affiliations

1 College of Agronomy, Northwest A&F University, Yangling 712100, China

2 State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang 455000, China

3 Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces NM 88003, USA

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BMC Genomics 2014, 15:466  doi:10.1186/1471-2164-15-466

Published: 12 June 2014

Abstract

Background

The 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).

Results

A 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.

Conclusions

Our 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.

Keywords:
Gossypium hirsutum; Fuzzless-lintless mutant; Fiber initiation; Phosphoproteomics