Table 3. Plasmids used in this study.

Plasmid	Description	Reference
pFAJ1700	Broad-host-range IncP plasmid, TcR	[69]
pFAJ1708	pFAJ1700 containing nptII promoter	[69]
pFUS2	oriC ColE1 oriT RK2 lacZ transcriptional reporter; suicide vector, GmR	[62]
pIJ3200	Broad-host-range IncP plasmid, TcR	[70]
pPH1JI	IncP plasmid, GmR	[71]
pJQ200SK	Suicide vector containing sacB gene, GmR	[65]
pJS100	pFAJ1700 containing nifA2 and preceding 626 bp	This study
pJS101	pFAJ1700 containing the 626 bp that precedes nifA2 fused at the start codon to the complete nifA1 gene	This study
pJS102	pFAJ1700 containing rpoN1 and preceding 118 bp	This study
pJS103	pFAJ1700 containing the 570 bp that precedes prxS fused at the start codon to the complete rpoN2 gene	This study
pJS104	pFAJ1700 containing fixV and preceding 295 bp	This study
pJS105	pFAJ1700 containing msi158 and preceding 392 bp	This study
pJS106	pFAJ1700 containing msi262 and preceding 739 bp	This study
pJS107	pFAJ1700 containing 279 bp upstream of nifB, with in-frame deletion of nifB and complete fdxN, nifZ and fixU genes	This study
pJS108	pFAJ1700 containing the nifB promoter region, with the 5′ end of nifB fused in-frame to the 3′ end of fdxN, and complete nifZ and fixU genes.	This study
pJS109	pFAJ1700 containing the nifB promoter region, with the 5′ end of nifB fused in-frame to the 3′ end of nifZ, and complete fixU gene.	This study
pJS110	pFAJ1700 containing nifQ cloned behind nptII promoter	This study