High-throughput monoclonal antibody array generation and its application in metabolomics of cultivated strawberry

Antibodies are essential for elucidating the function of genes decoded by genome sequencing. However, an effectively technology for proteome-scale antibody generation in strawberry has been developed not too much. In this study, the Proteome Epitope Tag Antibody Library (PETAL) and its array were developed to identify the key proteins during strawberry fruit ripening. Analysis of the entire proteome from strawberry fruits of the cultivars 'Zijin Jiuhong' and 'Tokun' at six key development stages (from receptacle to fully red fruit) enabled construction of a PETAL consisting of 7,000 monoclonal antibodies (mAbs) against 8,954 proteins. Screening in these mAbs using an array chip, 846 differential antibodies were chosen for western blot (WB) identification, and 123 qualified antibodies were selected. Gas chromatograph-mass spectrometry (GC-MS) analysis of different stages of strawberry fruit development showed that 18 proteins were identified and most proteins were major members in sugar or acid metabolism, plus other primary energetic metabolism. Crucially, our microarray assays indicated that some pivotal proteins including alcohol dehydrogenase class-3, fructose-bisphosphate aldolase, phosphoglucomutase, and their target proteins were related the regulation of fruit ripening. In conclusion, by generating a large-scale mAb library, we provided valuable antibodies for strawberry and identified potential key regulators controlling the fruit-ripening process.