Physiological and transcriptional regulation in poplar roots and leaves during acclimation to high temperature and drought.
To elucidate the physiological and transcriptional regulatory mechanisms that underlie the responses of poplars to high temperature (HT) and/or drought in woody plants, we exposed Populus alba × Populus tremula var. glandulosa saplings to ambient temperature (AT) or HT under 80 or 40% field capacities (FC), or no watering. HT increased the foliar total carbon (C) concentrations, and foliar δ(13) C and δ(18) O. HT triggered heat stress signaling via increasing levels of abscisic acid (ABA) and indole-3-acetic acid (IAA) in poplar roots and leaves. After perception of HT, poplars initiated osmotic adjustment by increasing foliar sucrose and root galactose levels. In agreement with the HT-induced heat stress and the changes in the levels of ABA and carbohydrates, we detected increased transcript levels of HSP18 and HSP21, as well as NCED3 in the roots and leaves, and the sugar transporter gene STP14 in the roots. Compared with AT, drought induced greater enhancement of foliar δ(13) C and δ(18) O in poplars at HT. Similarly, drought caused greater stimulation of the ABA and foliar glucose levels in poplars at HT than at AT. Correspondingly, desiccation led to greater increases in the mRNA levels of HSP18, HSP21, NCED3, STP14 and INT1 in poplar roots at HT than at AT. These results suggest that HT has detrimental effects on physiological processes and it induces the transcriptional regulation of key genes involved in heat stress responses, ABA biosynthesis and sugar transport and HT can cause greater changes in drought-induced physiological and transcriptional responses in poplar roots and leaves.
College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, P. R. China.
Jingbo
J
Jia
College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, P. R. China.
Shaojun
S
Li
College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, P. R. China.
Xu
X
Cao
College of Plant Protection, Northwest A&F University, Yangling, 712100, P. R. China.
Hong
H
Li
College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, P. R. China.
Wenguang
W
Shi
Büsgen-Institute, Department of Forest Botany and Tree Physiology, Georg-August University, Göttingen, 37077, Germany.
Andrea
A
Polle
College of Plant Protection, Northwest A&F University, Yangling, 712100, P. R. China.
Tong-Xian
TX
Liu
Key Laboratory of Environment and Ecology in Western China of Ministry of Education, College of Forestry, Northwest A&F University, Yangling, 712100, P. R. China.
Changhui
C
Peng
College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, P. R. China.|Key Laboratory of Environment and Ecology in Western China of Ministry of Education, College of Forestry, Northwest A&F University, Yangling, 712100, P. R. China.
Zhi-Bin
ZB
Luo
D000040:Abscisic Acid / Q000378:metabolism; D000064:Acclimatization; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D032107:Populus / Q000235:genetics / Q000502:physiology*; D013696:Temperature
D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid; D000040:Abscisic Acid