Transgenic soybean overexpressing GmSAMT1 exhibits resistance to multiple-HG types of soybean cyst nematode Heterodera glycines.
Jingyu Lin, Mitra Mazarei, Nan Zhao, Catherine N Hatcher, Wegi A Wuddineh, Mary Rudis, Timothy J Tschaplinski, Vincent R Pantalone, Prakash R Arelli, Tarek Hewezi, Feng Chen, Charles Neal Stewart
Author Information
Jingyu Lin: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Mitra Mazarei: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Nan Zhao: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
Catherine N Hatcher: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Wegi A Wuddineh: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Mary Rudis: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Timothy J Tschaplinski: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
Vincent R Pantalone: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Prakash R Arelli: Crop Genetics Research Unit, USDA-ARS, Jackson, TN, USA.
Tarek Hewezi: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Feng Chen: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Charles Neal Stewart: Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA. nealstewart@utk.edu.
soybean (Glycine max (L.) Merr.) salicylic acid methyl transferase (GmSAMT1) catalyses the conversion of salicylic acid to methyl salicylate. Prior results showed that when GmSAMT1 was overexpressed in transgenic soybean hairy roots, resistance is conferred against soybean cyst nematode (SCN), Heterodera glycines Ichinohe. In this study, we produced transgenic soybean overexpressing GmSAMT1 and characterized their response to various SCN races. Transgenic plants conferred a significant reduction in the development of SCN HG type 1.2.5.7 (race 2), HG type 0 (race 3) and HG type 2.5.7 (race 5). Among transgenic lines, GmSAMT1 expression in roots was positively associated with SCN resistance. In some transgenic lines, there was a significant decrease in salicylic acid titer relative to control plants. No significant seed yield differences were observed between transgenics and control soybean plants grown in one greenhouse with 22 °C day/night temperature, whereas transgenic soybean had higher yield than controls grown a warmer greenhouse (27 °C day/23 °C night) temperature. In a 1-year field experiment in Knoxville, TN, there was no significant difference in seed yield between the transgenic and nontransgenic soybean under conditions with negligible SCN infection. We hypothesize that GmSAMT1 expression affects salicylic acid biosynthesis, which, in turn, attenuates SCN development, without negative consequences to soybean yield or other morphological traits. Thus, we conclude that GmSAMT1 overexpression confers broad resistance to multiple SCN races, which would be potentially applicable to commercial production.
