Co-occurrence of tannin and tannin-less vacuoles in sensitive plants.

Vacuoles of different types frequently coexist in the same plant cell, but the duality of the tannin/tannin-less vacuoles observed in Mimosa pudica L. is rare. In this plant, which is characterized by highly motile leaves, the development and original features of the double vacuolar compartment were detailed in primary pulvini from the young to the mature leaf stage.

Dissection of the transcriptional regulation of grape ASR and response to glucose and abscisic acid.

Despite the fact that the precise physiological function of ASRs [abscisic acid (ABA), stress, ripening] remains unknown, they have been suggested to play a dual role in the plant response to environmental cues, as highly hydrophilic proteins for direct protection, as well as transcription factors involved in the regulation of gene expression. To investigate further the biological positioning of grape ASR in the hormonal and metabolic signal network, three promoters corresponding to its cDNA were isolated and submited to a detailed in silico and functional analysis. The results obtained provided evidence for the allelic polymorphism of the grape ASR gene, the organ-preferential expression conferred on the GUS reporter gene, and the specific phloem tissue localization revealed by in situ hybridization.

Interaction of grape ASR proteins with a DREB transcription factor in the nucleus.

ASR proteins (abscissic acid, stress, ripening induced) are involved in plant responses to developmental and environmental signals but their biological functions remain to be elucidated. Grape ASR gene (VvMSA) encodes a new transcription factor regulating the expression of a glucose transporter. Here, we provide evidence for some polymorphism of grape ASRs and their identification as chromosomal non-histone proteins.

Overexpression of the VvLTP1 gene interferes with somatic embryo development in grapevine.

Grapevine (Vitis vinifera L.) embryos have an early developmental pattern which differs from the one observed in model angiosperms such as Arabidopsis, in that the plane of divisions show variations from one individual to another. Furthermore, the protoderm (the first tissue to differentiate) does not form in one step but rather, gradually with time during globule formation.