Sugar levels altered by ectopic expression of a yeast-derived invertase affect cellular differentiation of developing cotyledons of Vicia narbonensis L.

Abstract

In order to change the sugar status during seed development a yeast-derived invertase gene was expressed in cotyledons of Vicia narbonensis. As a result, sucrose decreased whereas hexoses accumulated. We analysed cell structure and cellular differentiation in cotyledons expressing the yeast-invertase. Transgenic cells contained large and long-persisting vacuoles apparently serving as storage compartments for hexoses and clusters of storage-protein aggregates. In the wild-type, large vacuoles did not persist but were replaced by smaller protein bodies. During maturation and desiccation, the transgenic cells showed plasmolysis and vesiculation of the endo-membrane system. Immunogold-labelling revealed that the storage proteins vicilin and legumin were present within the cytoplasm and the extraprotoplasmic space and were attached to membranes of the endoplasmic reticulum and the nuclei. Protein storage vacuoles in mature seeds appeared heterogeneous and only partially filled. The data suggest that sugars control the subcellular organisation of the vacuolar system. Transcript levels encoding a tonoplast intrinsic protein, a marker for membranes of protein storage vacuoles, remained unchanged whereas mRNA levels of a hexose and a sucrose transporter increased. Generally, transgenic seeds appeared to be physiologically younger than wild-type seeds of the same age. The data underline the important role of sugars in legume seed development.

Glucose and ethylene signalling pathways converge to regulate trans‐differentiation of epidermal transfer cells in Vicia narbonensis cotyledons

“…Intracellular glucose blockage of trans ‐differentiation of adaxial epidermal cells to TC morphology is consistent with its known function of maintaining developing cotyledons in a de‐differentiated state (Weber et al. , 1996, 1998; Neubohn et al. , 2000).…”

Expression of a Plant Cell Wall Invertase in Roots of Arabidopsis Leads to Early Flowering and an Increase in Whole Plant Biomass

“…When we used this truncated promoter to drive CIN1 expression, transgenic ppyk10C::CIN1 plants showed apparent changes with respect to their flowering time, morphology, and biomass. Most studies addressing related questions so far have used a yeast cell wall invertase with a signal peptide for apoplastic targeting (von Schaewen et al, 1990;Sonnewald et al, 1991;Bussis et al, 1997;Sonnewald et al, 1997;Weber et al, 1998;Neubohn et al, 2000;Zuther et al, 2004;Heyer et al, 2004). However, when we expressed the same yeast cell wall invertase (kindly provided by Prof. U. Sonnewald) under control of the pyk10C promoter, we could not observe any effects comparable with those found for the ppyk10C::CIN1 plants, as described below.…”

Seed Development and Differentiation: A Role for Metabolic Regulation

“…In addition, cell differentiation is altered in the transgenic cotyledons lacking sucrose. The cells appear developmentally younger and are strongly disturbed within the subcellular organisation of the vacuolar system (Neubohn et al, 2000). In potato tubers, the expression of invertase (Trethewey et al, 1998) or sucrose phosphorylase (Trethewey et al, 2001) bypasses sucrose synthase and decreases sucrose levels.…”