Manipulation of monoubiquitin improves chilling tolerance in transgenic tobacco (Nicotiana tabacum).
Ubiquitin (Ub) is a multifunctional protein that mainly functions to tag proteins for selective degradation by the 26S proteasome. We cloned an Ub gene TaUb2 from wheat (Triticum aestivum L.) previously. To study the function of TaUB2 in chilling stress, sense and antisense Ub transgenic tobacco plants (Nicotiana tabacum L.), as well as wild type (WT) and vector control β-glucuronidase (T-GUS) plants, were used. Under stress, leaf wilting in sense plants was significantly less than in controls, but more severe in antisense plants. Meanwhile, the net photosynthetic rate (Pn) and the maximal photochemical efficiency of PSII (Fv/Fm) in sense plants were greater than controls, but lower in antisense plants during chilling stress and recovery. Less wilting in sense plants resulted from improved water status, which may be related to the accumulation of proline and solute sugar. Furthermore, as indicated by electrolyte leakage, membrane damage under stress was less in sense plants and more severe in antisense plants than controls. Consistent with electrolyte leakage, the malondialdehyde (MDA) content was less in sense plants, but more in antisense plants compared to controls. Meanwhile, the less accumulation of reactive oxygen species (ROS) and the greater antioxidant enzyme activity in sense plants implied the improved antioxidant competence by the overexpression of monoubiquitin gene Ta-Ub2 from wheat. We suggest that overexpressing Ub is a useful strategy to promote chilling tolerance. The improvement of ROS scavenging may be an important mechanism underlying the role of Ub in promoting plants tolerant to chilling stress.
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Yanan
Y
Feng
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Meng
M
Zhang
State Key Laboratory of Crop Biology, College of Agriculture, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Qifang
Q
Guo
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Guokun
G
Wang
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Jiangfeng
J
Gong
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Ying
Y
Xu
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong 271018, PR China. Electronic address: wangw@sdau.edu.cn.
Wei
W
Wang
D000222:Adaptation, Physiological / Q000235:genetics*; D000975:Antioxidants / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D003080:Cold Temperature; D017343:Genes, Plant; D005966:Glucuronidase / Q000235:genetics; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014908:Triticum / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D025801:Ubiquitin / Q000235:genetics* / Q000378:metabolism; D014867:Water / Q000502:physiology
D000975:Antioxidants; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D025801:Ubiquitin; D014867:Water; D008315:Malondialdehyde; D011392:Proline; D005966:Glucuronidase
APX; CAT; Chilling tolerance; E1; E2; E3; Fv/Fm; MDA; NBT; POD; Photosynthesis; Pn; ROS; Reactive oxygen species; SOD; T-GUS; Transgenic tobacco plants; UPS; Ub; Ub/26S proteasome system; Ubiquitin; WT; Wheat; actual efficiency of PSII; ascorbate peroxidase; catalase; malondialdehyde; maximal efficiency of PSII photochemistry; nitroblue tetrazolium; pBI-GUS; peroxidase; photosynthetic rate; reactive oxygen species; superoxide dismutase; the transgenic plants carrying the recombinant construct of GUS gene; ubiquitin; ubiquitin-activating enzyme; ubiquitin-conjugating enzyme; ubiquitin-protein ligase; vector control, carrying the recombinant construct of the β-glucuronidase gene alone under the control of CaMV 35S promoter and the nopaline synthase 3′ termination sequences in the sense orientation; wild-type; ФPSII