Open AccessTrigonelline and Stachydrine Released from Alfalfa Seeds Activate NodD2 Protein in Rhizobium meliloti
Author(s) -
Donald A. Phillips,
Cecillia M. Joseph,
Carl A. Maxwell
Publication year - 1992
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.99.4.1526
Subject(s) - trigonelline , medicago sativa , rhizobium , lotus japonicus , biology , nod , legume , fabaceae , biochemistry , lotus , lathyrus , medicago , gene , botany , mutant
Spectroscopic data (nuclear magnetic resonance, mass spectrometry, ultraviolet-visible) in this study identify trigonelline and stachydrine as major components of alfalfa (Medicago sativa L.) seed rinse. Moreover, biological assays show that these natural products induce nodulation (nod) gene transcription in Rhizobium meliloti by activating the regulatory protein NodD2, but not the homologous NodD1 protein. These findings contrast with the fact that the only previously identified NodD2 activator, 4,4' -dihydroxy-2' -methoxychalcone (MCh), also activates NodD1 protein. Trigonelline and stachydrine induce nod genes only at much higher concentrations than MCh, but they are released from seeds in correspondingly greater amounts. The existence of these amphoteric, nonflavonoid nod gene inducers broadens our understanding of the biochemical processes and ecological mechanisms that a legume host uses to regulate its microbial symbiont.