TABLE 1.

Plasmids and bacterial strains used in this study

Plasmid or strain	Relevant characteristic(s)	Reference or source
pFAJ1171	pUC18 derivative containing the promoterless gusA gene from pBI101.3 on a 2-kb BamHI-EcoRI fragment	25
pFAJ870	pFAJ1171 derivative containing a 517-bp fragment from the cytN gene of A. brasilense Sp7	This study
pFAJ873	pLAFR3 derivative containing a 2.6-kb PstI-EcoRI fragment from pFAJ870	This study
pLAFR3	Broad-host-range vector, Tcr	21
Azospirillum brasilense Sp7	Wild type (= ATCC 29145)	22
Escherichia coli DH5α	hsdR17 endA1 thi-1 gyrA96 relA1 recA1 supE44 ΔlacU169 (Φ80lacZ ΔM15)	Gibco-BRL