Overexpression of a soybean salicylic acid methyltransferase gene confers resistance to soybean cyst nematode

• Published in: Plant biotechnology journal Vol. 11; no. 9; pp. 1135 - 1145
• Main Authors: Lin, Jingyu, Mazarei, Mitra, Zhao, Nan, Zhu, Junwei J., Zhuang, Xiaofeng, Liu, Wusheng, Pantalone, Vincent R., Arelli, Prakash R., Stewart, Charles N., Chen, Feng
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.12.2013
• Subjects: Acid resistance; Acids; Amino Acid Sequence; Animals; Biosynthesis; Disease Resistance; DNA microarrays; DNA, Complementary - genetics; E coli; Enzymes; Escherichia coli; Flowers & plants; Gene expression; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Genomics; Genotype; Glycine max - enzymology; Glycine max - genetics; Glycine max - immunology; Hairy root; Heterodera glycines; Infections; Kinases; Kinetics; methyl salicylate; Methyltransferases - genetics; Methyltransferases - metabolism; Molecular Sequence Data; Nematoda; Pathogens; Pest resistance; Phylogeny; Plant Diseases - immunology; Plant Diseases - parasitology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant resistance; Plant Roots - enzymology; Plant Roots - genetics; Plant Roots - immunology; Plants, Genetically Modified; Roots; Salicylic acid; Salicylic Acid - metabolism; Salicylic acid methyltransferase; Sequence Alignment; Signal Transduction; soybean; Soybeans; transgenic hairy roots; Tylenchoidea - physiology; soybean; methyl salicylate; Heterodera glycines; transgenic hairy roots
• ISSN: 1467-7644; 1467-7652
• DOI: 10.1111/pbi.12108

Summary Salicylic acid plays a critical role in activating plant defence responses after pathogen attack. Salicylic acid methyltransferase (SAMT) modulates the level of salicylic acid by converting salicylic acid to methyl salicylate. Here, we report that a SAMT gene from soybean (GmSAMT1) plays a role in soybean defence against soybean cyst nematode (Heterodera glycines Ichinohe, SCN). GmSAMT1 was identified as a candidate SCN defence‐related gene in our previous analysis of soybean defence against SCN using GeneChip microarray experiments. The current study started with the isolation of the full‐length cDNAs of GmSAMT1 from a SCN‐resistant soybean line and from a SCN‐susceptible soybean line. The two cDNAs encode proteins of identical sequences. The GmSAMT1 cDNA was expressed in Escherichia coli. Using in vitro enzyme assays, E. coli‐expressed GmSAMT1 was confirmed to function as salicylic acid methyltransferase. The apparent Km value of GmSAMT1 for salicylic acid was approximately 46 μm. To determine the role of GmSAMT1 in soybean defence against SCN, transgenic hairy roots overexpressing GmSAMT1 were produced and tested for SCN resistance. Overexpression of GmSAMT1 in SCN‐susceptible backgrounds significantly reduced the development of SCN, indicating that overexpression of GmSAMT1 in the transgenic hairy root system could confer resistance to SCN. Overexpression of GmSAMT1 in transgenic hairy roots was also found to affect the expression of selected genes involved in salicylic acid biosynthesis and salicylic acid signal transduction.