TABLE 2.

Expression of phlA-gfp or prnA-gfp reporter fusions in P. fluorescens CHA0 in the rhizosphere of different plant species^a

Reporter fusion	Trial	No. of gated events (108 per g of root)b	No. of CFUc		Relative fluorescence
			% of gfp-expressing cells	Per g of root (107)	Per gated eventd	Per g of root (1010)e
phlA-gfp	Wheat	7.9 ABe	14 AB	7.9 A	33.1 A	2.7 AB
	Triticale	22.3 AB	7 A	11.6 AB	32.2 A	7.2 A
	Barley	23.8 AB	6 A	14.8 AB	26.0 B	6.1 AB
	Maize	4.7 AB	4 A	2.3 A	41.0 C	2.0 AB
	Turnip	16.0 AB	18 AB	31.9 B	22.3 B	3.7 AB
	Cress	26.9 A	10 A	16.3 AB	21.2 B	5.8 AB
	Tomato	2.1 AB	28 B	6.2 A	28.9 AB	0.6 B
	Cucumber	1.0 B	87 C	9.1 AB	28.0 AB	0.7 B
prnA-gfp	Wheat	4.1 A	8 A	2.3 B	34.1 A	1.4 B
	Triticale	2.7 A	15 A	3.7 AB	34.2 A	0.9 B
	Barley	4.5 A	22 A	9.7 AB	30.6 AB	1.4 B
	Maize	1.1 A	7 A	4.2 AB	48.3 C	0.7 B
	Turnip	10.8 AB	22 A	12.1 A	36.6 A	3.8 AB
	Cress	21.2 B	6 A	11.7 A	31.8 AB	6.4 A
	Tomato	0.6 A	34 AB	2.6 B	17.8 D	0.1 B
	Cucumber	0.8 A	63 B	4.4 AB	23.8 BD	2.7 AB

^aPlant seedlings were inoculated with CHA0/pME7100 carrying a phlA-gfp fusion or with CHA0/pME7116 carrying a prnA-gfp fusion and grown in growth pouches as described in Materials and Methods. Gene expression in root washes was measured after 10 days by FACS-based flow cytometry. Means of three replicates per treatment are given. The experiment has been repeated once with similar results (data not shown). Values in the same column for the same reporter fusion followed by different letters are significantly different according to Fisher's protected LSD (P ≤ 0.05).

^bCells expressing reporter fusions.

^cThe number of CFU corresponding to culturable cells was determined by serial plating on KMB agar containing tetracycline.

^dRelative fluorescence per gated event (cell) reflects the average phlA-gfp or prnA-gfp expression per active CHA0 cell.

^eRelative fluorescence per root weight reflects the total phlA-gfp or prnA-gfp expression per root weight.