Overexpression of OrbHLH001, a putative helix-loop-helix transcription factor, causes increased expression of AKT1 and maintains ionic balance under salt stress in rice.
The basic helix-loop-helix family of proteins, which function as transcription factors, have been intensively studied in plants and animals. However, the molecular mechanism of these factors contributing to stress tolerance is unknown. Here, we report on the overexpression of OrbHLH001 from Dongxiang wild rice (Oryza rufipogon) conferring salt tolerance in transgenic rice plants. The expression of OrbHLH001 was tissue specific, mainly in phloem tissues throughout the plant. Ion assay with the scanning ion-selective electrode technique showed that NaCl stress has a greater influence on Na(+) efflux and K(+) influx in OrbHLH001-overexpressed plants than the wild type. OrbHLH001 protein can induce the expression of OsAKT1 to regulate the Na(+)/K(+) ratio in OrbHLH001-overexpressed plants by specifically binding to an E-box motif in the promoter region of OsAKT1. The mechanism may have potential use in rice molecular breeding.
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Yuan
Y
Chen
Fei
F
Li
Yan
Y
Ma
Kang
K
Chong
Yunyuan
Y
Xu
D000595:Amino Acid Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D024721:E-Box Elements; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins; D017736:Ion-Selective Electrodes; D008969:Molecular Sequence Data; D012275:Oryza / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D052585:Phloem / Q000166:cytology / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011188:Potassium / Q000032:analysis / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D055049:Salt Tolerance; D016415:Sequence Alignment; D012964:Sodium / Q000032:analysis / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D020798:Two-Hybrid System Techniques
D051792:Basic Helix-Loop-Helix Proteins; D049452:Green Fluorescent Proteins; D010940:Plant Proteins; D011188:Potassium; D012964:Sodium; D012965:Sodium Chloride