title: Expression of terpenoid synthase mRNA and terpenoid content in salt stressed mangrove.
abstract: The halophytic Kandelia candel and Bruguiera gymnorrhiza are ideal model for studying the molecular mechanisms of salinity tolerance in mangrove plants. The correlation between mRNA expression of four oxidosqualene cyclase (OSC) genes namely, KcMS multifunctional terpenoid synthase and KcCAS cyloartenol synthase (K. candel), BgbAS beta-amyrin synthase and BgLUS lupeol synthase (B. gymnorrhiza) and salt concentration was examined. mRNA level of KcMS was increased with salt concentration in both roots and leaves of K. candel. Similarly, salt stress increased the mRNA levels of BgLUS and BgbAS in the root of B. gymnorrhiza. This result suggests that the function of terpenoids in root is associated with the salt stress. In contrast to these observations, the mRNA level of KcCAS was not modulated by salt stress in the roots, and decreased in the leaves. These results therefore suggest that the terpenoids but not phytosterols play an important role to cope with the salt stress in mangrove root. The content and proportion of beta-amyrin and lupeol increased with salinity in the root of K. candel and B. gymnorrhiza, providing additional evidence for the protective role of terpenoids. However, beta-amyrin and lupeol in B. gymnorrhiza leaves decreased with salt concentration, suggesting that the physiological significance for the terpenoids in the leaf may differ from that for the root.
authors.affiliation: University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Basyuni
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Baba
authors.forename: Masashi
authors.initials: M
authors.lastname: Inafuku
authors.forename: Hironori
authors.initials: H
authors.lastname: Iwasaki
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Kinjo
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Oku
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D008025:Ligases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D043982:Rhizophoraceae / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D012965:Sodium Chloride; D013312:Stress, Physiological; D013729:Terpenes / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D013729:Terpenes; D012965:Sodium Chloride; D008025:Ligases