Abstract:

In order to screen a strawberry gynoecium protein extraction method for mass spectrum (MS)-based proteomics studies, a new method named as phenol-chloroform extraction was established by adding a chloroform extraction step to the traditional phenol extraction method, and the application on extracting strawberry gynoecium proteins of the three methods: trichloroacetic acid/acetone precipitation (method Ⅰ), phenol extraction(method Ⅱ) and phenol-chloroform extraction (method Ⅲ) were evaluated. The analysis results of the total protein yield, sum of protein identification, subcellular location and hydrophilic-hydrophobic distribution of non-shared proteins showed that, the phenol-chloroform method was the most efficient and comprehensive for protein extraction. The protein yields of method Ⅰ, method Ⅱ and method Ⅲ were 0.20%, 0.12% and 0.27%, respectively; and the sum of protein identified were 5 170, 5 345, and 5 697, respectively. The Venn diagram analysis showed that method Ⅲ intersected most of the non-shared proteins of method Ⅰ and method Ⅱ. Subcellular location analysis showed that non-shared proteins of method Ⅰ and method Ⅲ were mainly distributed in the nucleus, whereas those of method Ⅱ were mainly distributed in the cytoplasm, indicating that the three methods had different subcellular preferences. Hydrophilic-hydrophobic analysis showed that method Ⅰ had the highest proportion of hydrophilic protein but insufficient hydrophobic protein extraction, while method Ⅱ had insufficient extraction of hydrophilic protein, and method Ⅲ took into account the extraction of both hydrophilic and hydrophobic proteins. According to the results, method Ⅲ should be the optimal protein extraction method for strawberry gynoecium.

Key words: strawberry, gynoecium, proteomics, extraction methods