Jasmonic acid influences mycorrhizal colonization in tomato plants by modifying the expression of genes involved in carbohydrate partitioning.
The role of jasmonic acid (JA) on mycorrhizal colonization by Glomus fasciculatum in tomato plants was examined using mutant plants overexpressing prosystemin (PS) or affected in the synthesis of JA (suppressor of prosystemin-mediated responses 2, spr2). The degree of mycorrhizal colonization was determined by measuring frequency (F%) and intensity (M%) of colonization and arbuscule abundance (A%). Gene expression and biochemical analyses were also performed in roots to detect changes in carbon (C) partitioning. Colonization was similar in mycorrhizal PS and wild-type roots, except for a higher A% in the former. Conversely, colonization was severely reduced in roots of spr2 mutants. No association was found between levels of expression of genes coding for systemic wound responsive proteins (or SWRPs) and other defense-related proteins in roots and mycorrhization levels in these plants. On the other hand, the degree of mycorrhizal colonization correlated with changes in the transcriptional regulation of a number of genes involved in sucrose hydrolysis and transport, cell wall invertase activity and mycorrhizal-specific fatty acid content in roots. The results obtained suggest that one of the mechanisms by which JA might operate to modulate the mycorrhization process could be through its influence on the regulation of C partitioning in the plant. The significant colonization increase observed in mycorrhizal spr2 plants supplied with exogenous methyl jasmonate supports its role as a positive regulator of the symbiosis.
Tejeda-Sartorius
Miriam
M
Unidad de Biotecnología e Ingeniería Genética de Plantas (Cinvestav-Campus Guanajuato), Km 9.6 del Libramiento Norte Carretera Irapuato-León, Apartado Postal 629, C.P. 36821, Irapuato, Guanajuato, México.
Martínez de la Vega
Octavio
O
Délano-Frier
John Paul
JP
D000085:Acetates / Q000494:pharmacology*; D050260:Carbohydrate Metabolism / Q000235:genetics*; D002473:Cell Wall / Q000187:drug effects / Q000201:enzymology; D003517:Cyclopentanes / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology*; D038821:Mycorrhizae / Q000187:drug effects*; D054883:Oxylipins / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000382:microbiology; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D043324:beta-Fructofuranosidase / Q000235:genetics / Q000378:metabolism
D000085:Acetates; D003517:Cyclopentanes; D005227:Fatty Acids; D054883:Oxylipins; D010940:Plant Proteins; D013395:Sucrose; D013213:Starch; C072239:methyl jasmonate; D005964:Glucosyltransferases; C022699:sucrose synthase; D043324:beta-Fructofuranosidase