Propagation of Ornamental Plants
8(3): 117-124, 2008
RNASE AND DNASE ACTIVITY AND ISOFORM PATTERNS DURING ADVENTITIOUS ROOT FORMATION IN CUTTINGS OF EBENUS CRETICA l.
Thomas Syros1,2, Traianos Yupsanis2*, Ioannis Karsisiotis2, Antoanela Patras2,3, and Athanasios Economou1,4
1 School of Agriculture, Aristotle University, 54124 Thessaloniki, Greece, *E-mail: yupsanis@chem.auth.gr 2 School of Chemistry, Aristotle University, 54124 Thessaloniki, Greece 3 School of Horticulture, Ion Ionescu de la Brad University, 700490 Iasi, Romania 4 Institute of Agrobiotechnology, CERTH, 570 01 Thermi-Thessaloniki, Greece
Abstract
The present study was conducted to study the quantitative and qualitative changes of RNases and DNases during rooting of Ebenus cretica cuttings, in order to associate them with root formation and relate them with the interdependent phases of rooting. Plants from RG (rooting genotype, 100% rooting) and NRG (non-rooting genotype, 0% rooting) were grown in the greenhouse under controlled environmental conditions. Terminal semi-hardwood cuttings were taken from the two genotypes with different rooting response and after the application of 0 or 0.5 g l-1 IBA were planted in perlite and placed for rooting in the fog. On day 0, 1, 4, 7, 11, 14, 18 and 21 after placement for rooting, a basal portion from the cuttings (about 2 cm) was cut and used for the determination of RNase and DNase specific activity at pH 5.5 and 7.5. Additionally, RNase and DNase patterns during the rooting process were analyzed (native-PAGE) on active RNA and DNA gels, respectively. RNase activity was higher at pH 5.5 (three orders of magnitude as compared to pH 7.5) for both RG and NRG. RNase activity (pH 5.5) in the cuttings of the RG increased from day 4 to day 14 during the rooting process with a peak on day 11 and day 7 (initiation phase) for the control and the IBA-treated cuttings respectively, and was higher in the control than in the IBA-treated cuttings. On the other hand, in the cuttings of the NRG, the respective RNase activity slightly increased from day 0 to day 11 during the rooting process, with a peak on day 4 and day 1 (induction phase) for the control and the IBA-treated cuttings, respectively. The control (day 0) cuttings from RG and NRG revealed different RNase electrophoretic patterns. A new fast migrating RNase isoform (R4) mainly appeared in the RG genotype in the course of adventitious rooting which could be related with the rooting process. DNase activity was higher at pH 7.5 for both RG and NRG. This activity increased from day 1 to day 21 and was higher in NRG (four orders of magnitude) for both the control and the IBA-treated cuttings. DNase isoform patterns were similar for RG and NRG in the control cuttings on day 0 of rooting. An additional D3 DNase isoform revealed only in RG. R2 and R3 RNase isoforms and D3 DNase isoform (on day 0) could be used as biochemical markers for selection of Ebenus cretica genotypes for successful adventitious rooting.
Key words: electrophoresis, IBA, native PAGE; nucleases, vegetative propagation
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