Identification of a retroelement from the resurrection plant Boea hygrometrica that confers osmotic and alkaline tolerance in Arabidopsis thaliana.
Functional genomic elements, including transposable elements, small RNAs and non-coding RNAs, are involved in regulation of gene expression in response to plant stress. To identify genomic elements that regulate dehydration and alkaline tolerance in Boea hygrometrica, a resurrection plant that inhabits drought and alkaline Karst areas, a genomic DNA library from B. hygrometrica was constructed and subsequently transformed into Arabidopsis using binary bacterial artificial chromosome (BIBAC) vectors. Transgenic lines were screened under osmotic and alkaline conditions, leading to the identification of Clone L1-4 that conferred osmotic and alkaline tolerance. Sequence analyses revealed that L1-4 contained a 49-kb retroelement fragment from B. hygrometrica, of which only a truncated sequence was present in L1-4 transgenic Arabidopsis plants. Additional subcloning revealed that activity resided in a 2-kb sequence, designated Osmotic and Alkaline Resistance 1 (OAR1). In addition, transgenic Arabidopsis lines carrying an OAR1-homologue also showed similar stress tolerance phenotypes. Physiological and molecular analyses demonstrated that OAR1-transgenic plants exhibited improved photochemical efficiency and membrane integrity and biomarker gene expression under both osmotic and alkaline stresses. Short transcripts that originated from OAR1 were increased under stress conditions in both B. hygrometrica and Arabidopsis carrying OAR1. The relative copy number of OAR1 was stable in transgenic Arabidopsis under stress but increased in B. hygrometrica. Taken together, our results indicated a potential role of OAR1 element in plant tolerance to osmotic and alkaline stresses, and verified the feasibility of the BIBAC transformation technique to identify functional genomic elements from physiological model species.
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Yan
Y
Zhao
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Tao
T
Xu
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Chun-Ying
CY
Shen
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Guang-Hui
GH
Xu
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Shi-Xuan
SX
Chen
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Li-Zhen
LZ
Song
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Mei-Jing
MJ
Li
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Li-Li
LL
Wang
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Yan
Y
Zhu
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Wei-Tao
WT
Lv
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China.
Zhi-Zhong
ZZ
Gong
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Chun-Ming
CM
Liu
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Xin
X
Deng
D000222:Adaptation, Physiological / Q000235:genetics*; D060054:Agrobacterium / Q000235:genetics; D000468:Alkalies / Q000633:toxicity*; D017360:Arabidopsis / Q000502:physiology*; D022202:Chromosomes, Artificial, Bacterial; D019686:Lamiaceae / Q000235:genetics*; D009997:Osmotic Pressure; D030821:Plants, Genetically Modified; D060888:Real-Time Polymerase Chain Reaction; D018626:Retroelements; D013312:Stress, Physiological; D014170:Transformation, Genetic
D000468:Alkalies; D018626:Retroelements