Functional Characterization of Mi, a Root-knot Nematode Resistance Gene from Tomato （ Lycopersicon esculentum L.）  

作　　者：Ru-Gang Chen Li-Ying Zhang Jun-Hong Zhang Wei Zhang Xue Wang Bo Ouyang Han-Xia Li Zhi-Biao Ye 

机构地区：[1]National Key Laboratory of Crop Genetic Improvement, Wuhan 430070, China [2]National Center for Vegetable Improvement, Huazhong Agricultural University, Wuhan 430070, China

出　　处：《Journal of Integrative Plant Biology》2006年第12期1458-1465,共8页植物学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China （30370980）, Doctorate Program of University of Ministry of Education （20050504028）, and National Advanced Technology Research and Development Plan of China （AA212221）.

摘　　要：Root-knot nematodes （Meloidogyne spp.） cause major economic damage to numerous crop species around the world. Plant resistance is the most important attribute that is able to suppress invasion by the rootknot nematodes. In the present study, a candidate root-knot nematode resistance gene （Mi） was isolated from the resistant tomato （Lycopersicon esculentum L.） line RN-1. Expression profiling analysis revealed that this gene was expressed specifically in the roots, stems, and leaves, but not in the flowers or fruits. To verify the real function of this candidate gene, both sense and inteference RNA （RNAi） vectors were constructed. We obtained 31 transgenic plants with between one and seven copies of T-DNA inserts of sense Mi from two nematode-susceptible tomato cultivars as assayed by polymerase chain reaction （PCR） and Southern blotting analysis. Reverse transcription-PCR analysis revealed that expression levels of the Mi gene varied in different transgenic plants. Nematode assays showed that the resistance to root-knot nematodes was significantly improved in some transgenic lines compared with untransformed susceptible controls and that the resistance was heritable in selfed progeny. Loss of function via RNAi further confirmed the role of the Mi gene and the original resistant lines became susceptible to root-knot nematodes.Root-knot nematodes （Meloidogyne spp.） cause major economic damage to numerous crop species around the world. Plant resistance is the most important attribute that is able to suppress invasion by the rootknot nematodes. In the present study, a candidate root-knot nematode resistance gene （Mi） was isolated from the resistant tomato （Lycopersicon esculentum L.） line RN-1. Expression profiling analysis revealed that this gene was expressed specifically in the roots, stems, and leaves, but not in the flowers or fruits. To verify the real function of this candidate gene, both sense and inteference RNA （RNAi） vectors were constructed. We obtained 31 transgenic plants with between one and seven copies of T-DNA inserts of sense Mi from two nematode-susceptible tomato cultivars as assayed by polymerase chain reaction （PCR） and Southern blotting analysis. Reverse transcription-PCR analysis revealed that expression levels of the Mi gene varied in different transgenic plants. Nematode assays showed that the resistance to root-knot nematodes was significantly improved in some transgenic lines compared with untransformed susceptible controls and that the resistance was heritable in selfed progeny. Loss of function via RNAi further confirmed the role of the Mi gene and the original resistant lines became susceptible to root-knot nematodes.

关 键 词：Mi gene OVEREXPRESSION RNAI root-knot nematode TOMATO 

分 类 号：Q96[生物学—昆虫学]