Differential manifestation of seed mortality induced by seed-specific expression of the gene for diphtheria toxin A chain in Arabidopsis and tobacco

• Published in: Molecular & general genetics Vol. 235; no. 1; p. 33
• Main Authors: Czako, M. (South Carolina Univ., Columbia (USA). Dept. of Biological Sciences), Jang, J.C, Herr, J.M. Jr, Marton, L
• Format: Journal Article
• Language: English
• Published: Germany 01.10.1992
• Subjects: Arabidopsis; Arabidopsis - embryology; Arabidopsis - genetics; Cloning, Molecular; CRUCIFERAE; DESARROLLO EMBRIONARIO; DEVELOPPEMENT EMBRYONNAIRE; Diphtheria toxin; Diphtheria Toxin - genetics; Diphtheria Toxin - metabolism; Embryogenesis; EMBRYONIC DEVELOPMENT; EXPRESION GENICA; EXPRESSION DES GENES; Fabaceae - genetics; GENE EXPRESSION; Genetic ablation; Genetic Vectors; Nicotiana - embryology; Nicotiana - genetics; NICOTIANA TABACUM; Organ Specificity - genetics; Pea vicilin promoter; Plant Proteins; Plant Proteins, Dietary - genetics; Plants, Medicinal; Plants, Toxic; Promoter Regions, Genetic; Restriction Mapping; SEED; Seed Storage Proteins; Seeds - genetics; Seeds - growth & development; SEMENCE; SEMILLAS; TOXINAS; TOXINE; TOXINS
• ISSN: 0026-8925; 1432-1874
• DOI: 10.1007/bf00286178

A pea vicilin promoter-diphtheria toxin A (DTx-A) chain gene fusion was introduced into Arabidopsis and tobacco. The chimeric Dtx-A gene behaves as a dominant, seed-lethal, Mendelian factor, and the segregation ratios are consistent with the numbers of integrated copies as revealed by Southern blotting. Germination deficiency results from distinct developmental abnormalities, thus allowing genetic dissection of seed development. The endosperm is affected first in both species. In Arabidopsis, full cellularization of the initially syncytial endosperm does not take place, which results in shrinkage and a shriveled appearance of the mature dry seed. The embryo, which appears structurally normal and lacks visible lesions, ceases to develop at the partially recurved cotyledon stage and does not use the remaining endosperm. In tobacco, peripheral degeneration and premature termination of cellular endosperm development occurs at the cotyledon initiation stage. Lesions appear in the cotyledons at the advanced cotyledon stage, but the embryo continues to grow and attains nearly the same size and level of differentiation as mature wild-type embryos before degeneration and intracellular disintegration take place throughout. Accumulation of protein bodies and other cytoplasmic inclusions is very limited and occurs only in few cells. The timing and distribution of lesions follow a pattern typical for accumulation of protein bodies in wild-type seeds. These observations are consistent with expression of the vicilin promoter in the enlargement phase of cell differentiation. A novel tissue interaction arises, when the embryo uses up all the arrested endosperm: the embryo proves to be capable of absorbing the parenchyma layers of the integument, which are normally obliterated by, and incorporated into, the endosperm.