Expression Patterns Of SICMO In The Halophyte Suaeda Liaotungensis K. And PC-CMO Transgenic Tobacco Under Abiotic Stresses

Glycine betaine is an osmoticum playing a major role in plant resistance to osmoticstress. Because choline monooxygenase (CMO) is the key enzyme in glycine betainesynthesis, an understanding of CMO expression patterns in plants is important.Semi-quantitative reverse transcription-PCR and quantitative real-time PCR assaysrevealed that the expression of SlCMO in leaves, stems and roots of S. liaotungensis andpC-CMO transgenic tobaccos.S. liaotungensis, SlCMO was expressed strongly in stems, weakly in leaves, andmarginally in roots under normal conditions. Under salt, low temperature, and drought stressconditions in S. liaotungensis, SlCMO expression in leaves, stems, and roots increasedsignificantly. Upon removal of these stresses, expression returned to nearly original levelswithin72h. Our study indicates that SlCMO is induced under salt, low temperature, anddrought stress conditions in S. liaotungensis. Under ABA stress conditions in S. liaotungensis,SlCMO expression in leaves, stems, and roots is inducible.In pC-CMO transgenic tobacco, SlCMO was expressed strongly in leaves, weakly instems, and marginally in roots. Under salt, low temperature, and drought stress conditions inpC-CMO transgenic, SlCMO expression in leaves, stems, and roots increased. Upon removalof these stresses, expression returned to nearly original levels within72h. SlCMO was notinduced by ABA in pC-CMO transgenic tobacco. These results suggest that the pC promoter(-267~+1) can act as a stress-induced promoter, but is not as responsive as it is in S.liaotungensis.In this study, we characterized SlCMO expression patterns in S. liaotungensis andpC-CMO transgenic tobacco. We observed similar trends in both organisms in response tosalt, low temperature, and drought conditions with one main exception: SlCMO was inducedby ABA stress in S. liaotungensis but not in pC-CMO transgenic tobacco. These resultssuggest that a truncated version of the pC promoter still containing essential abioticstress-responsive elements could serve as an important tool in the study of abiotic stressresistance in transgenic plants.