Overexpression of a wheat jasmonate-regulated lectin increases pathogen resistance.
Jasmonates are known to induce the transcriptional activation of plant defense genes, which leads to the production of jasmonate-regulated proteins (JRP). We previously cloned and characterized a novel jacalin-like lectin gene (Ta-JA1) from wheat (Triticum aestivum L.), which codes a modular JRP with disease response and jacalin-related lectin (JRL) domains and is present only in the Gramineae family. The function of this protein is still unclear. Phylogenetic analysis indicated that Ta-JA1 and related proteins from cereals grouped together, which diverged from JRL with an additional N-terminal disease response domain. The recombinant Ta-JA1 proteins agglutinated rabbit erythrocytes, and this hemagglutination activity was preferentially inhibited by mannose. The Ta-JA1 protein was able to inhibit E. coli cell growth. Overexpression of Ta-JA1 in transgenic tobacco plants increased their resistance to infection by tobacco bacterial, fungal and viral pathogens. Our results suggest that Ta-JA1 belongs to a mannose-specific lectin, which may confer a basal but broad-spectrum resistance to plant pathogens. Ta-JA1 and its homologues in maize, rice, sorghum and creeping bentgrass may represent a new type of monocot lectin with a modular structure and diversity of physiological functions in biotic and abiotic stress responses.
Ma
Qing-Hu
QH
Institute of Botany, Chinese Academy of Sciences, Beijing, China. mqh@ibcas.ac.cn
Tian
Bing
B
Li
Yun-Liang
YL
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D003517:Cyclopentanes / Q000378:metabolism*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects; D015870:Gene Expression; D007113:Immunity, Innate / Q000235:genetics*; D008358:Mannose / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D010802:Phylogeny; D010935:Plant Diseases / Q000276:immunology; D037121:Plant Lectins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011817:Rabbits; D013379:Substrate Specificity; D014026:Nicotiana / Q000235:genetics / Q000276:immunology; D014908:Triticum / Q000235:genetics*
D003517:Cyclopentanes; D054883:Oxylipins; D037121:Plant Lectins; C043696:jacalin; C011006:jasmonic acid; D008358:Mannose