title: In vitro function of S rnases in Lycopersicon peruvianum.
abstract: S RNases are products of the S locus that are expressed in the stylar tissue of Lycopersicon peruvianum with the gametophytic self-incompatibility (SI) system. Two S RNases (S12 and Sa) with RNase activity from the S12Sa genotype of L. peruvianum were purified using gel filtration and cation-exchange chromatography. The molecular masses of the two RNases, S12 and Sa, were 21 and 23.1 kDa, respectively. The specific activities of S12 and Sa for torula yeast rRNA as a substrate were 8,500 and 6,000 units/ml, respectively. Of various reagents tested for RNase activities, ZnSO4 and CuSO4 were found to remarkably reduce its activity. The growth of S12Sa pollen was inhibited when it was cultured in a pollen germination medium that contained the purified S12 RNase. The result suggested that the S RNase was either a probable inhibitor of pollen growth or controlled pollen growth. Additionally, 512Sa pollens germinated well in vitro in a germination medium that contained S12 RNase in the presence of ZnSO4 and CuSO4. Our finding suggests that the treatment of S RNase with its inhibitor destroys the SI ability on an in vitro self-pollen growth test.
authors.affiliation: Faculty of Life Resources, Catholic University of Taegu, Kyungsan, Korea.
authors.forename: M H
authors.initials: MH
authors.lastname: Kim
authors.forename: D I
authors.initials: DI
authors.lastname: Shin
authors.forename: H S
authors.initials: HS
authors.lastname: Park
authors.forename: I K
authors.initials: IK
authors.lastname: Chung
mesh_terms: D007527:Isoenzymes / Q000378:metabolism*; D011058:Pollen / Q000378:metabolism; D012098:Reproduction; D012260:Ribonucleases / Q000378:metabolism*; D019657:Solanaceae / Q000201:enzymology* / Q000235:genetics
chemical_list: D007527:Isoenzymes; D012260:Ribonucleases; C077002:ribonuclease Sa3; C424719:S12 RNase