Rhizobium inoculation and physical wounding result in the rapid induction of the same chalcone synthase copy in Trifolium subterraneum

• Published in: Molecular plant-microbe interactions Vol. 7; no. 4; pp. 498 - 507
• Main Authors: Lawson, C.G.R, Djordjevic, M.A, Weinman, J.J, Rolfe, B.G
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.07.1994
• Subjects: ABIOTIC INJURIES; Acyltransferases - biosynthesis; Agronomy. Soil science and plant productions; ARN MENSAJERO; ARN MESSAGER; Base Sequence; Biological and medical sciences; chs gene; COMPLEMENTARY DNA; Economic plant physiology; Enzyme Induction - drug effects; EXPRESION GENICA; EXPRESSION DES GENES; Fabaceae - drug effects; Fabaceae - enzymology; Fabaceae - microbiology; Fabaceae - physiology; FORMATION DE NODOSITES; Fundamental and applied biological sciences. Psychology; GENE; GENE EXPRESSION; GENES; Lipopolysaccharides - pharmacology; MESSENGER RNA; Molecular Sequence Data; Multigene Family; NARINGENIN-CHALCONE SYNTHASE; NODULACION; NODULATION; NUCLEOTIDE SEQUENCE; Plants, Medicinal; RACINE; RAICES; RHIZOBIUM LEGUMINOSARUM; Rhizobium leguminosarum - growth & development; RHIZOBIUM MELILOTI; RHIZOBIUM TRIFOLII; ROOT NODULATION; ROOTS; SECUENCIA NUCLEICA; SEQUENCE NUCLEIQUE; STRUCTURAL GENES; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); TRANSFERASAS; TRANSFERASE; TRANSFERASES; TRIFOLIUM SUBTERRANEUM; Acyltransferases; Symbionte; Rhizobium meliloti; Enzyme; Induction; Transferases; Vegetal microorganism relation; Trifolium subterraneum; Rhizobium leguminosarum bv. trifolii; Infection; Inoculation; Leguminosae; Naringenin-chalcone synthase; Dicotyledones; Angiospermae; Bacteria; Spermatophyta; Rhizobiaceae; Fodder crop
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-7-0498

The gene or genes encoding chalcone synthase (CHS) in the legume Trifolium subterraneum (subterranean clover) were induced within 6 hr after inoculation with Rhizobium leguminosarum bv. trifolii strain ANU843. No induction was found in uninoculated controls or plants inoculated with either the nodulation-deficient R. l. bv. trifolii strain ANU845 (pSym-) or R. meliloti strain 1021, which is capable of nodulating alfalfa but not clover. Morphological examination of the interaction between the legume and bacteria in this system showed that root hair distortion (a marker of the early events in the interaction) was apparent within 10 hr after inoculation. This indicated that CHS induction could occur before any detectable sign of rhizobial penetration of root hairs. The addition of a crude preparation of R. l. bv. trifolii lipooligosaccharide signals (Nod metabolites) to the plant growth medium had no effect on the expression of CHS over 36 hr, although root hair distortion was apparent over this time. These treatments were then contrasted with physical wounding. Wounding the plants led to a rapid induction of CHS, occurring within 2 hr. Sequence analysis of cloned CHS cDNA from pools sampled after Rhizobium inoculation or wounding treatments showed the gene designated CHS5 was the major CHS species in both treatments. Conserved sequences were found in promoters of CHS5 and soybean Gmchs7, a gene which has overlapping expression patterns. These findings support the view that the induction of the phenylpropanoid pathway is involved in the very early events of the Rhizobium infection of legumes.