Events Associated with Early Age-Related Decline in Adventitious Rooting Competence of Eucalyptus globulus Labill
Open Access
- 10 October 2017
- journal article
- research article
- Published by Frontiers Media SA in Frontiers in Plant Science
- Vol. 8, 1734
- https://doi.org/10.3389/fpls.2017.01734
Abstract
The development of adventitious roots is affected by several factors, including the age of the cutting donor plant, which negatively affects rooting capacity. Eucalyptus globulus quickly loses rooting capacity of cuttings as the donor plant ages, although the molecular and biochemical mechanisms behind this process are still unclear. To better understand the bases of rooting competence loss in E. globulus, the time required for a significant decline in rhizogenic ability without exogenous auxin was determined in microcuttings derived from donor plants of different ages after sowing. Tip cuttings of donor plants were severed before and after loss of rooting competence of microcuttings to test the hypothesis that auxin and carbohydrate homeostasis regulate rooting competence decline. There were no significant changes in concentration of carbohydrates, flavonoids, or proteins before and after the loss of rooting capacity. Peroxidase (EC 1.11.1.7) total activity increased with loss of rooting competence. Auxin concentration showed the opposite pattern. In good agreement, TAA1, a key gene in auxin biosynthesis, had lower expression after loss of rooting capacity. The same applied to the auxin receptor gene TIR1, suggesting reduced auxin sensitivity. On the other hand, genes associated with auxin response repression (TPL, IAA12) or with the action of cytokinins, the rhizogenesis inhibitor-related ARR1, showed higher expression in plants with lower rooting competence. Taken together, data suggest that age negatively affects E. globulus rooting by a combination of factors. Decreased endogenous auxin concentration, possibly caused by less biosynthesis, lower auxin sensitivity, higher expression of genes inhibiting auxin action, as well as of genes related to the action of cytokinins, appear to play roles in this process.Keywords
Funding Information
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (306079/2013-5)
This publication has 50 references indexed in Scilit:
- Auxin and cytokinin control formation of the quiescent centre in the adventitious root apex of arabidopsisAnnals of Botany, 2013
- When stress and development go hand in hand: main hormonal controls of adventitious rooting in cuttingsFrontiers in Plant Science, 2013
- Primer3—new capabilities and interfacesNucleic Acids Research, 2012
- Conversion of tryptophan to indole-3-acetic acid by TRYPTOPHAN AMINOTRANSFERASES OF ARABIDOPSIS and YUCCAs in ArabidopsisProceedings of the National Academy of Sciences of the United States of America, 2011
- Reference gene selection for quantitative reverse transcription-polymerase chain reaction normalization during in vitro adventitious rooting in Eucalyptus globulus LabillBMC Molecular Biology, 2010
- The Cytokinin Type-B Response Regulator PtRR13 Is a Negative Regulator of Adventitious Root Development inPopulusPlant Physiology, 2009
- Type B Response Regulators of Arabidopsis Play Key Roles in Cytokinin Signaling and Plant DevelopmentTHE PLANT CELL ONLINE, 2008
- A new mathematical model for relative quantification in real-time RT-PCRNucleic Acids Research, 2001
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976
- A Revised Medium for Rapid Growth and Bio Assays with Tobacco Tissue CulturesPhysiologia Plantarum, 1962