Mini Review ARTICLE
Engineering Drought Resistance in Forest Trees
- 1Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, China
- 2Georg-August-Universität Göttingen, Germany
- 3Zentrum für Biodiversität und nachhaltige Landnutzung, Georg-August-Universität Göttingen, Germany
- 4Abteilung für Forstbotanik und Baumphysiologie, Georg-August-Universität Göttingen, Germany
- 5Dipartimento per l'innovazione nei sistemi biologici, agroalimentari e forestali, Università della Tuscia, Italy
Climatic stresses limit plant growth and productivity. In the past decade, tree improvement programs were mainly focused on yield but it is obvious that enhanced stress resistance is also required. In this review we highlight important drought avoidance and tolerance mechanisms in forest trees. Genomes of economically important trees species with divergent resistance mechanisms can now be exploited to uncover the mechanistic basis of long-term drought adaptation at the whole plant level. Molecular tree physiology indicates that osmotic adjustment, antioxidative defense and increased water use efficiency are important targets for enhanced drought tolerance at the cellular and tissue level. Recent biotechnological approaches focused on overexpression of genes involved in stress sensing and signaling, such as the abscisic acid core pathway and down-stream transcription factors. By this strategy, a suite of defense systems was recruited, generally enhancing drought and salt stress tolerance under laboratory conditions. However, field studies are still scarce. Under field conditions trees are exposed to combinations of stresses that vary in duration and magnitude. Variable stresses may overrule the positive effect achieved by engineering an individual defense pathway. To assess the usability of distinct modifications, large-scale experimental field studies in different environments are necessary. To optimize the balance between growth and defense, the use of stress-inducible promoters may be useful. Future improvement programs for drought resistance will benefit from a better understanding of the intricate networks that ameliorate molecular and ecological traits of forest trees.
Keywords: Antioxidative systems, Genetic Engineering, Physiological traits, Forest tree species, isohydric and anisohydric plants, avoidance, tolerance, Water limitation, biomass, Defense
Received: 10 Aug 2018;
Accepted: 04 Dec 2018.
Edited by:Wout Boerjan, Flanders Institute for Biotechnology, Belgium
Reviewed by:Chung-Jui Tsai, University of Georgia, United States
Christine H. Foyer, University of Leeds, United Kingdom
Copyright: © 2018 Polle, Chen, Eckert and Harfouche. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Andrea Polle, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China, firstname.lastname@example.org