Expression of Soluble and Wall-bound Acid Invertases in Different Tissue of Lilium longiflorum Flower Buds

Abstract

In mature Lilium longiflorum flower buds, anther and stigma had the highest soluble acid invertase activity [3.29 and 2.31 μmol of reducing sugars (RS)/min per gram of fresh weight (FW), respectively] compared to style, ovary, petal, and filament with activities of 1.52, 1.08, 0.99 and 0.98 μmol RS/min per gram of FW, respectively. DEAE-sephacel chromatography revealed that invertase activity in petal, ovary, style, and stigma was composed exclusively of invertase II and III isoforms. Anther invertase was mainly invertase I with small amounts of invertase II and III. Filament tissue mainly had invertase II and III isoforms with a small amount of invertase I. Wall-bound invertases were extracted with 1.0 m NaCl. Anthers had the highest wall-bound invertase activity (4.42 μmol RS/min per gram of FW) followed by stigma (0.42 μmol RS/min per gram of FW). Other tissues had low wall-bound invertase activity (<0.1 μmol RS/min per gram FW). For further purification, the binding of soluble invertases to nine different reactive dyes was investigated. Invertase I was bound to Reactive Green 5, Reactive Green 19, and Reactive Red 120 columns and was eluted with 0.5 m NaCl, resulting in increase in specific activity ≈10-fold with ≈70% recovery. Invertase II and III bound only to Reactive Red 120. Elution with 0.5 m NaCl resulted in an ≈6-fold increase in specific activity.