tailieunhanh - Báo cáo khoa học: A DExD⁄ H box RNA helicase is important for K+ deprivation responses and tolerance in Arabidopsis thaliana

The molecular mechanism for sensing and transducing the stress signals ini-tiated by K + deprivation in plants remains unknown. Here, we found that the expression of AtHELPS,anArabidopsisDExD⁄H box RNA helicase gene, was induced by low-K + , zeatin and cold treatments, and downregu-lated by high-K + stress. | ễFEBS Journal A DExD H box RNA helicase is important for K deprivation responses and tolerance in Arabidopsis thaliana Rui-Rui Xu Sheng-Dong Qi Long-Tao Lu Chang-Tian Chen Chang-Ai Wu and Cheng-Chao Zheng State Key Laboratory of Crop Biology College of Life Sciences Shandong AgriculturalUniversity Taian China Keywords Arabidopsis thaliana DExD H-box RNA helicase K deprivation K flux seed germination Correspondence Cheng-Chao Zheng or Chang-Ai Wu College of Life Sciences Shandong Agricultural University Taian Shandong 271018 China Fax 86 538 8226399 or 86 538 8246205 Tel 86 538 8242894 or 86 538 8241318 E-mail cczheng@ or cawu@ Received 26 January 2011 revised 22 April 2011 accepted 28 April 2011 doi The molecular mechanism for sensing and transducing the stress signals initiated by K deprivation in plants remains unknown. Here we found that the expression of AtHELPS an Arabidopsis DExD H box RNA helicase gene was induced by low-K zeatin and cold treatments and downregu-lated by high-K stress. To further investigate the expression pattern of AtHELPS pAtHELPS GUS transgenic plants were generated. Histochemical staining indicated that AtHELPS is mainly expressed in the young seedlings and vascular tissues of leaves and roots. Using both helps mutants and overexpression lines we observed that in the low-K condition AtHELPS affected Arabidopsis seed germination and plant weight. Interestingly the mRNA levels of AKT1 CBL1 9 and CIPK23 in the helps mutants were much higher than in the overexpression lines under low-K stress. Moreover under low-K stress the helps mutants displayed increased K influx whereas the overexpression line of AtHELPS had a lower flux rate in the roots by the noninvasive micro-test technique. Taken together these results provide information for the functional analysis of plant DEVH box RNA helicases and suggest that AtHELPS as an important negative regulator plays a role in K deprivation stress.