Molecular and physiological responses to abiotic stress in forest trees and their relevance to tree improvement.
Abiotic stresses, such as drought, salinity and cold, are the major environmental stresses that adversely affect tree growth and, thus, forest productivity, and play a major role in determining the geographic distribution of tree species. Tree responses and tolerance to abiotic stress are complex biological processes that are best analyzed at a systems level using genetic, genomic, metabolomic and phenomic approaches. This will expedite the dissection of stress-sensing and signaling networks to further support efficient genetic improvement programs. Enormous genetic diversity for stress tolerance exists within some forest-tree species, and due to advances in sequencing technologies the molecular genetic basis for this diversity has been rapidly unfolding in recent years. In addition, the use of emerging phenotyping technologies extends the suite of traits that can be measured and will provide us with a better understanding of stress tolerance. The elucidation of abiotic stress-tolerance mechanisms will allow for effective pyramiding of multiple tolerances in a single tree through genetic engineering. Here we review recent progress in the dissection of the molecular basis of abiotic stress tolerance in forest trees, with special emphasis on Populus, Pinus, Picea, Eucalyptus and Quercus spp. We also outline practices that will enable the deployment of trees engineered for abiotic stress tolerance to land owners. Finally, recommendations for future work are discussed.
Department for Innovation in Biological, Agro-food and Forest systems, University of Tuscia, Via S. Camillo de Lellis, Viterbo 01100, Italy.
Antoine
A
Harfouche
Department of Forestry and Natural Resources, Purdue University, 715 West State Street, West Lafayette, IN 47907-2061, USA.
Richard
R
Meilan
Faculty of Agricultural, Food and Environmental Quality Sciences, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel arie.altman@mail.huji.ac.il.
Arie
A
Altman
D000222:Adaptation, Physiological; D018533:Biomass; D055864:Droughts; D057890:Epigenomics; D065928:Forests; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D005818:Genetic Engineering; D014644:Genetic Variation; D023281:Genomics; D019684:Magnoliopsida / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010641:Phenotype; D015398:Signal Transduction; D013312:Stress, Physiological; D019076:Transgenes; D014197:Trees / Q000235:genetics / Q000254:growth & development / Q000502:physiology
acclimation; epigenetic control; genetic variation; natural population; regulatory networks; signaling; stress; tolerance; tree growth