

López-Baena FJ et al.Regulation and symbiotic sign...[PMID: 18524937]
PMID -18524937
OWN -NLM
STAT -In-Process
DA -20080605
PUBM -print
IS -1350-0872 (Print)
VI -154
IP -Pt 6
DP -2008 Jun
TI -Regulation and symbiotic significance of nodulation outer proteins secretion in Sinorhizobium fredii HH103.
PG -1825-36
AB -In this work we show that the Sinorhizobium fredii HH103 ttsI gene is essential for the expression of the tts genes and secretion of nodulation outer proteins (Nops). Moreover, we demonstrate for the first time, to our knowledge, that the nod box preceding ttsI is necessary for Nops secretion. TtsI is responsible for the transcriptional activation of nopX, nopA, rhcJ and rhcQ. We confirm that the S. fredii HH103 ttsI gene is activated by NodD1 and repressed by NolR. In contrast, NodD2 is not involved in the regulation of ttsI expression. Despite the dependence of expression of both ttsI and nodA on NodD1 and flavonoids, clear differences in the capacity of some flavonoids to activate these genes were found. The expression of the ttsI and nodA genes was also sensitive to differences in the pH of the media. Secretion of Nops in the ttsI mutant could not be complemented with a DNA fragment containing the ttsI gene and its nod box, but it was restored when a plasmid harbouring the ttsI, rhcC2 and y4xK genes was transferred to the mutant strain. The symbiotic effect of Nops secretion was host-dependent but independent of the type of nodule formed by the host legume. Nops are beneficial in the symbiosis with Glycine max and Glycyrrhiza uralensis, and detrimental in the case of the tropical legume Erythrina variegata.
AD -Departamento de Microbiologia, Facultad de Biologia, Universidad de Sevilla, Sevilla, Spain.
FAU -Lopez-Baena, Francisco Javier
AU -Lopez-Baena FJ
FAU -Vinardell, Jose Maria
AU -Vinardell JM
FAU -Perez-Montano, Francisco
AU -Perez-Montano F
FAU -Crespo-Rivas, Juan Carlos
AU -Crespo-Rivas JC
FAU -Bellogin, Ramon A
AU -Bellogin RA
FAU -Espuny, Maria Del Rosario
AU -Espuny Mdel R
FAU -Ollero, Francisco Javier
AU -Ollero FJ
LA -eng
SI -GENBANK/AY184383
PT -Journal Article
PT -Research Support, Non-U.S. Gov't
PL -England
TA -Microbiology
JT -Microbiology (Reading, England)
JID -9430468
SB -IM
EDAT -2008/06/06 09:00
MHDA -2008/06/06 09:00
AID -154/6/1825 [pii]
AID -10.1099/mic.0.2007/016337-0 [doi]
PST -ppublish
SO -Microbiology. 2008 Jun;154(Pt 6):1825-36.