tailieunhanh - Báo cáo khoa học: NtKTI1, a Kunitz trypsin inhibitor with antifungal activity from Nicotiana tabacum, plays an important role in tobacco’s defense response

A cDNA library from tobacco inoculated withRhizoctonia solaniwas con-structed, and several cDNA fragments were identified by differential hybridization screening. One cDNA clone that was dramatically repressed, NtKTI1, was confirmed as a member of the Kunitz plant proteinase inhibi-tor family. RT-PCR analysis revealed that NtKTI1was constitutively expressed throughout the whole plant and preferentially expressed in the roots and stems. | ễFEBS Journal NtKTII a Kunitz trypsin inhibitor with antifungal activity from Nicotiana tabacum plays an important role in tobacco s defense response Hao Huang Sheng-Dong Qi Fang Qi Chang-Ai Wu Guo-Dong Yang and Cheng-Chao Zheng State Key Laboratory of Crop Biology College of Life Sciences Shandong AgriculturalUniversity China Keywords antifungalactivity Kunitz trypsin inhibitor prokaryotic expression Rhizoctonia solani transgenic tobacco Correspondence . Zheng State Key Laboratory of Crop Biology College of Life Sciences Shandong AgriculturalUniversity Taian Shandong 271018 China Fax 86 538 8226399 Tel 86 538 8242894 E-mail cczheng@ These authors contributed equally to this work Database The nucleotide sequence of NtKTI1 is available in the GenBank database under accession number FJ494920 Received 20 May 2010 revised 21 July 2010 accepted 30 July 2010 doi A cDNA library from tobacco inoculated with Rhizoctonia solani was constructed and several cDNA fragments were identified by differential hybridization screening. One cDNA clone that was dramatically repressed NtKTIl was confirmed as a member of the Kunitz plant proteinase inhibitor family. RT-PCR analysis revealed that NtKTIl was constitutively expressed throughout the whole plant and preferentially expressed in the roots and stems. Furthermore RT-PCR analysis showed that NtKTIl expression was repressed after R. solani inoculation mechanical wounding and salicylic acid treatment but was unaffected by methyl jasmonate abscisic acid and NaCl treatment. In vitro assays showed that NtKTI1 exerted prominent antifungal activity towards R. solani and moderate antifungal activity against Rhizopus nigricans and Phytophthora parasitica var. nicoti-anae. Bioassays of transgenic tobacco demonstrated that overexpression of NtKTIl enhanced significantly the resistance of tobacco against R. solani and the antisense lines exhibited higher susceptibility than control lines towards