Proteomics of isolated sieve tubes from Nicotiana tabacum : sieve element–specific proteins reveal differentiation of the endomembrane system

Abstract

Significance Sieve elements are crucially important plant cells that distribute photoassimilates and communicate developmental and defensive signals throughout the plant body. They remain the least understood cell type in plants nonetheless, defying standard research methods as they are exceedingly sensitive and possess neither nucleus (no DNA) nor protein synthesis. We developed a protocol to isolate sieve elements for proteome analysis and discovered unfamiliar sieve element–specific proteins that define an internal differation of the endoplasmic reticulum—which demonstrates the power of this approach to the elusive sieve element.