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Total proteins extracted from developmental mutants of Arabidopsis thaliana (L.) Heyhn. and from wild-type plants cultivated in the presence of various hormones were analyzed by two-dimensional (2-D) gel electrophoresis. Computer analysis of 2-D gels followed by a statistical treatment of data allowed us to build a phenogram that describes the biochemical distances between the different genotypes. Analysis of the 2-D electrophoresis data allowed us to discriminate mutants in agreement with phenotypical and physiological traits. This biochemical analysis helped us to develop a working hypothesis which led us to show that one developmental mutant ( cri1 ) overaccumulates cytokinins. [ABSTRACT FROM AUTHOR]

A new class of recessive Arabidopsis mutants, designated cristal ( cri ) has been isolated which display several abnormalities reminiscent of hyperhydric symptoms. These characteristics include translucent and wrinkled cotyledons and leaves, abnormal chloroplast organization, a reduced amount of chlorophyll, a reduced dry weight and a decreased number of palisade cells in the leaves accompanied by an increase of intercellular space, and therefore give a vitreous appearance to the aerial part. The phenotype is also dependent on the culture medium water potential. The cri1 gene was mapped on chromosome 4 close to the DHS1 marker. [ABSTRACT FROM AUTHOR]

Total proteins extracted from wild-type plants of Arabidopsis thaliana Heyhn, an etiolated mutant, a de-etiolated mutant and a mutant affected in cotyledon morphology, were analyzed by two-dimensional gel electrophoresis. Computer analysis of two-dimensional gels allowed the characterization of the mutants by a set of proteins showing a differential expression when compared with the wild-type plant grown under the same conditions. The overlap between comparisons of the diferent mutants with the wild-type allowed the identification of groups of polypeptides which, since their expression is altered in several mutants, might be involved in certain physiological functions. For example, this approach showed a possible involvement of actin in the elongation process. The simultaneous analysis of the two-dimensional protein patterns of different mutants seems, therefore, to be a promising approach to characterize proteins involved in various physiological functions. [ABSTRACT FROM AUTHOR]

The auxin sensitivity of the plasma-membrane H-ATPase from tobacco leaves ( Nicotiana tabacum L. cv. Xanthi) depends on the physiological state of the plant (Santoni et al., 1990, Plant Sci. 68, 33-38). Results based on the study of auxin sensitivity according to culture conditions which accelerate or delay tobacco development demonstrate that the highest auxin sensitivity is always associated with the end of the period of induction to flowering. Auxin stimulation of H-translocation activity corresponds to an increase of the apparent ATPase affinity for ATP. The plasma-membrane H-ATPase content, measured with an enzyme-linked immunosorbent assay using a specific anti-H-ATPase antibody, varies according to plant development, and was found to increase by 100% during floral induction. The specific molecular ATPase activity also changes according to plant development; more particularly, the decrease in molecular ATPase activity upto and during the floral-induction period parallels the increase of sensitivity to indole-3-acetic acid. [ABSTRACT FROM AUTHOR]