漆酶基因OsLAC6在水稻应答亚砷酸盐胁迫中的作用

Role of Laccase Gene OsLAC6 in Response to Arsenite Stress in Rice

对OsLAC6基因的表达模式以及野生型日本晴和超表达OsLAC6基因水稻株系的漆酶活性、根系木质素含量、亚砷酸盐胁迫耐受性及亚砷酸盐胁迫条件下叶绿素、过氧化氢含量等进行分析,以期明确OsLAC6基因在水稻亚砷酸盐胁迫应答中的作用。结果表明,OsLAC6基因具有明显的时空表达特性,其在分蘖期和成熟期的根系、茎和叶片及分蘖期节中表达量较高。超表达OsLAC6基因极显著提高了转基因水稻株系叶片中漆酶活性,降低了水稻根系中木质素含量及对亚砷酸盐的耐受性。亚砷酸盐处理后,与野生型对照相比,超表达OsLAC6基因水稻株系的根系相对伸长量、叶绿素含量显著降低,叶片过氧化氢含量增加。综上,OsLAC6基因负调控水稻对亚砷酸盐的耐受性。

The expression pattern of laccase gene OsLAC6,as well as laccase activity,lignin content in the roots,phenotypes of arsenite tolerance,and the changes of contents of chlorophyll and H_(2)O_(2) of wild type(WT)and transgenic rice lines overexpressing OsLAC6 gene under arsenite stress were examined,so as to uncover the role of OsLAC6 gene in response to arsenic stress in rice.The results showed that the OsLAC6 gene exhibited apparently temporal and spatial expression pattern,which was mainly expressed in the roots,stems,leaves and nodes of rice plants at tillering stage and roots,stems leaves of rice plants at mature stage.Overexpression of OsLAC6 gene extensively significantly increased the laccase activity,but decreased lignin content in roots and the arsenite tolerance of transgenic rice lines.Under arsenite treatment,transgenic rice lines overexpressing OsLAC6 gene exhibited significantly shorter relative root elongation,lower chlorophyll content in leaves,and higher H_(2)O_(2) content compared with WT.Therefore,OsLAC6 negatively regulates the arsenite tolerance in rice.