Dynamic changes in alpha- and beta-amylase activities and gene expression in bulbs of the Oriental hybrid lily 'Siberia' during dormancy release

摘要

The commercial production of cut lilies depends on a synchronous release of dormancy in bulbs kept under cold storage. We investigated the effects of storage at 4 degrees C, 0 degrees C, or -1.5 degrees C, on dormancy release in bulbs of the Oriental hybrid Lilium 'Siberia' used for cut lily production. Cold storage at 4 degrees C for 8 weeks resulted in full elongation of the central bud in bulbs and 100% shoot emergence within 3 weeks of planting, indicating complete release of dormancy. Starch breakdown, increased soluble sugar concentrations, and the induction of alpha-amylase activity occurred with significant changes in bulbs in week-8 of cold storage. Two cDNAs, one for the alpha-amylase gene, LiAMY, and the other for the beta-amylase gene, LiBAM, were isolated and identified from 'Siberia' lily bulbs. Real-time reverse transcriptase quantitative PCR (RT-qPCR) analysis showed that expression of both LiAMY and LiBAM increased significantly in week-8 of cold storage. These changes were correlated with release from dormancy in commercial flowering bulbs of 'Siberia' lily.