Salt-induced expression of genes related to Na(+)/K(+) and ROS homeostasis in leaves of salt-resistant and salt-sensitive poplar species.
Using the Affymetrix poplar genome array, we explored the leaf transcriptome of salt-tolerant Populus euphratica Oliv. and salt-sensitive P. popularis 35-44 (P. popularis) under control and saline conditions. Our objective was to clarify the genomic differences in regulating K(+)/Na(+) and reactive oxygen species (ROS) homeostasis between the two species. Compared to P. popularis, salt-tolerant P. euphratica responses to salinity involved induction of a relatively larger number of probesets after short-term (ST) exposure to 150 mM NaCl (24 h) and relatively fewer probesets after a long-term (LT) exposure to salinity (200 mM NaCl, 28 days). Compared to P. popularis, leaves of the control P. euphratica plants exhibited a higher transcript abundance of genes related to Na(+)/H(+) antiport (Na(+)/H(+) antiporters, H(+) pumps) and K(+) uptake and transport. Notably, the expression of these genes did not decrease (with a few exceptions) during salt treatment. Regarding ROS homeostasis, P. euphratica exhibited rapid up-regulation of a variety of antioxidant enzymes after exposure to ST salinity, indicating a rapid adaptive response to salt stress. However, the effect of NaCl on transcription in P. popularis leaves was more pronounced after exposure to prolonged salinity. LT-stressed P. popularis up-regulated some genes mediating K(+)/Na(+) homeostasis but decreased transcription of main scavengers of superoxide radicals and H(2)O(2) except for some isoforms of a few scavengers. Mineral and ROS analyses show that NaCl induced a marked increase of leaf Na(+) and H(2)O(2) in LT-stressed plants of the two species and the effects were even more pronounced in the salt-sensitive poplar. We place the transcription results in the context of our physiological measurements to infer some implications of NaCl-induced alterations in gene expression related to K(+)/Na(+) and ROS homeostasis.
College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, People's Republic of China.
Mingquan
M
Ding
Peichen
P
Hou
Xin
X
Shen
Meijuan
M
Wang
Shurong
S
Deng
Jian
J
Sun
Fei
F
Xiao
Ruigang
R
Wang
Xiaoyang
X
Zhou
Cunfu
C
Lu
Deqiang
D
Zhang
Xiaojiang
X
Zheng
Zanmin
Z
Hu
Shaoliang
S
Chen
D016000:Cluster Analysis; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000235:genetics* / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055049:Salt Tolerance; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
D010940:Plant Proteins; D017382:Reactive Oxygen Species; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride; D012964:Sodium; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D011188:Potassium