Total Soluble Protein Extraction for Improved Proteomic Analysis of Transgenic Rice Plant Roots

With the advent of high-throughput platforms, proteomics has become a powerful tool to search for plant gene products of agronomic relevance. Protein extractions using multistep protocols have been shown to be effective to achieve better proteome profiles than simple, single-step extractions. These protocols are generally efficient for above ground tissues such as leaves. However, each step leads to loss of some amount of proteins. Additionally, compounds such as proteases in the plant tissues lead to protein degradation. While protease inhibitor cocktails are available, these alone do not seem to suffice when roots are included in the plant sample. This is obvious given the lack of high molecular weight (HMW) proteins obtained from samples that include root tissue. For protein/proteome analysis of transgenic plant roots or of seedlings, which include root tissue, such pronounced protein degradation is especially undesirable. A facile protein extraction protocol is presented, which ensures that despite the inclusion of root tissues there is minimal loss in total protein components.