Molecular study of drought response in the Mediterranean conifer Pinus pinaster Ait.: Differential transcriptomic profiling reveals constitutive water deficit‐independent drought tolerance mechanisms

ACKNOWLEDGMENTS I. Aranda (INIA-CIFOR) is gratefully acknowledged for his valuable collaboration and support in obtaining and interpreting data on physiology. D. Sobral (Instituto Gulbenkian de Ciência, Portugal) is gratefully acknowledged for his advice in the bioinformatics analyses. Bartolomé Sabater is gratefully acknowledged for critical review of the manuscript. S. Ferrándiz (INIA-CIFOR) is gratefully acknowledged for helping with the preparation of the manuscript. This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness (AGL2015-66048-C2-1-R; RTI2018-098015-B-I00; IMP2018-005)]; European Union's Seventh Framework Programme 2007-2013 (FP7-289841); EU H2020 Programme (H2020-676559); Fundação para a Ciência e a Tecnologia, FCT (IF/01168/2013; UID/Multi/04551/2013); and People Programme, Marie Curie Actions (PIEF-GA-2013-627761).
Adaptation of long-living forest trees to respond to environmental changes is essential to secure their performance under adverse conditions. Water deficit is one of the most significant stress factors determining tree growth and survival. Maritime pine (Pinus pinaster Ait.), the main source of softwood in southwestern Europe, is subjected to recurrent drought periods which, according to climate change predictions for the years to come, will progressively increase in the Mediterranean region. The mechanisms regulating pine adaptive responses to environment are still largely unknown. The aim of this work was to go a step further in understanding the molecular mechanisms underlying maritime pine response to water stress and drought tolerance at the whole plant level. A global transcriptomic profiling of roots, stems, and needles was conducted to analyze the performance of siblings showing contrasted responses to water deficit from an ad hoc designed full-sib family. Although P. pinaster is considered a recalcitrant species for vegetative propagation in adult phase, the analysis was conducted using vegetatively propagated trees exposed to two treatments: well-watered and moderate water stress. The comparative analyses led us to identify organ-specific genes, constitutively expressed as well as differentially expressed when comparing control versus water stress conditions, in drought-sensitive and drought-tolerant genotypes. Different response strategies can point out, with tolerant individuals being pre-adapted for coping with drought by constitutively expressing stress-related genes that are detected only in latter stages on sensitive individuals subjected to drought
Ministerio de Economía y Competitividad (España)
European Commission
Portuguese Foundation for Science and Technology
Depto. de Genética, Fisiología y Microbiología
Fac. de Ciencias Biológicas
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