Communication between the maternal testa and the embryo and/or endosperm affect testa attributes in tomato

• Published in: Plant physiology (Bethesda) 2003-09, Vol.133 (1), p.145-160
• Main Authors: Downie, A.B, Zhang, D, Dirk, L.M.A, Thacker, R.R, Pfeiffer, J.A, Drake, J.L, Levy, A.A, Butterfield, D.A, Buxton, J.W, Snyder, J.C
• Format: Article
• Language: English
• Subjects: alleles; anthocyanins; Anthocyanins - biosynthesis; Biological and medical sciences; catalase; Cell Communication - genetics; Cell Communication - physiology; Development and Hormone Action; embryo (plant); endosperm; Enzymes; Enzymes - genetics; Enzymes - metabolism; epidermis (plant); Fructification and ripening; Fruits; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; genetic complementation; Genetic Complementation Test; Genetic mutation; Genotypes; Germination; Germination - drug effects; Germination - physiology; gibberellic acid; Gibberellins - pharmacology; Lycopersicon esculentum - genetics; Lycopersicon esculentum - growth & development; Lycopersicon esculentum - metabolism; melanin; Melanins - biosynthesis; mutants; Mutation; peroxidase; pigmentation; Pigments; Pigments, Biological - biosynthesis; Pigments, Biological - chemistry; plant anatomy; Plant Epidermis - genetics; Plant Epidermis - growth & development; Plant Epidermis - metabolism; Plant physiology and development; plant proteins; Plants; Proanthocyanidins - biosynthesis; reactive oxygen species; Reactive Oxygen Species - metabolism; Seed germination; Seeds; Seeds - genetics; Seeds - growth & development; Seeds - metabolism; Solanum lycopersicum var. lycopersicum; superoxide dismutase; Testa; tomatoes; vegetable crops; Vegetative and sexual reproduction, floral biology, fructification
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.022632

Two tomato (Lycopersicon esculentum) mutants with dark testae displaying poor germination rate and percentage on both water and 100 μM $\text{gibberellin}_{4+7}$ were recovered. The mutants were allelic (black seed1-1; bks1-1 and bks1-2), inherited in Mendelian fashion as a recessive gene residing on chromosome 11. They are not allelic to bs (brown seed) -1, -2, or -4, which impair seed germination and possess dark testae. The bks/bs mutants accumulated dark pigment in the cell layers of the testa above the endothelium, which itself accumulated proanthocyanidins similar to wild type. The poor germination performance of bks mutant seeds was because of impediment of the mutant testae to radicle egress. Imbibition on $\text{gibberellin}_{4+7}$ did not ameliorate germination percentage or rate. The toughening of the bks testa and associated poor germination were partially overcome when seeds were not dried before germination or were dried under N2. The seeds of the bks mutant have elevated activity of at least one enzyme responsible for the detoxification of reactive oxygen species. The bks mutant is epistatic to 12 anthocyaninless mutants of tomato. Bio- and physicochemical analysis of the bks testa determined that it accumulated a melanic substance. Inheritance of bks/bs mutations contrasts with that of the anthocyaninless mutants, which are inherited according to the genotype of the maternally derived testa. This suggests that the testa manufactures components before its demise that can maximize testa strength, whereas the endosperm/embryo produces factors that are conveyed to the testa, mitigating this process.