relic S-RNase is expressed in the styles of self-compatible Nicotiana sylvestris

• Published in: The Plant journal : for cell and molecular biology Vol. 16; no. 5; pp. 591 - 599
• Main Authors: Golz, J.F, Clarke, A.E, Newbigin, E, Anderson, M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-12-1998; Blackwell Science
• Subjects: Agronomy. Soil science and plant productions; Amidohydrolases - metabolism; Amino Acid Sequence; amino acid sequences; Base Sequence; Biological and medical sciences; Cloning, Molecular; complementary DNA; DNA Primers - genetics; DNA, Complementary - genetics; DNA, Plant - genetics; enzyme activity; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; genbank/aj011532; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; genebank/aj002296; Genes, Plant; Genetics and breeding of economic plants; Heterosis. Floral biology applications: apomixy, male sterility, incompatibility, varia; Hydrolysis; Molecular Sequence Data; Nicotiana; Nicotiana - enzymology; Nicotiana - genetics; Nicotiana sylvestris; Nicotiana tabacum; nucleotide sequences; Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; Plant breeding: fundamental aspects and methodology; Plant physiology and development; Plants, Toxic; ribonucleases; Ribonucleases - genetics; self compatibility; self incompatibility; Sexual reproduction; species differences; Species Specificity; styles; Vegetative and sexual reproduction, floral biology, fructification; Nicotiana sylvestris; Purification; Enzyme; Biological evolution; Homology; Esterases; Ribonuclease; Gene expression; Sexual reproduction; Gynoecium; Conserved sequence; Selfincompatibility; Enzymatic activity; Complementary DNA; Dicotyledones; Angiospermae; N terminal-Sequence; Hydrolases; Spermatophyta; Solanaceae; Experimental plant; Plant reproductive apparatus; Aminoacid sequence
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1046/j.1365-313x.1998.00331.x

We surveyed ribonuclease activity in the styles of Nicotiana spp. and found little or no activity in self-compatible species and in a self-compatible of a self-incompatible species. All self-incompatible species had high levels of ribonuclease activity in their style. Interestingly, one self-compatible species, N. sylvestris, had a level of stylar ribonuclease activity comparable to that of some self-incompatible Nicotiana species. A ribonuclease with biochemical properties similar to those of the self-incompatibility (S-)RNases of N. alata was purified from N. sylvestris styles. The N-terminal sequence of this protein was used to confirm the identity of a cDNA corresponding to the stylar RNase. The amino acid sequence deduced from the cDNA was related to those of the S-RNases and included the five conserved regions characteristic of these proteins. It appears that the N. sylvestris RNase may have evolved from the S-RNases and is an example of a 'relic S-RNase'. A number of features distinguish the N. sylvestris RNase from the S-RNases, and the role these may have played in the presumed loss of the self-incompatibility response during the evolution of this species are discussed.