TABLE 2.

Experimental transmission of S. citri GII-3, GII3-9a2, GII3-9a5, and GII3-11cl to periwinkle (C. roseus) through injection to the leafhopper vector C. haematoceps

Expt	Inoculant	Plant	Living insectsa	CFU/ insectb	Symptomsc	CFU/g of midribsd
1	SP4 medium	P1	5		−
		P2	4		−	NDe
		P3	8		−	ND
	GII3 (wild type)	P1	6	1 × 106	+	5.7 × 106
		P2	4		+	ND
		P3	2		+	ND
	GII3-9a2 (Δspi)	P1	10	2.8 × 106	+ (2)	1.2 × 106
		P2	12		−
		P3	1		−
		P4	9		−
		P5	7		+ (4)	2.3 × 106
	GII3-9a5 (spi-gfp)	P1	9	4.9 × 105	+ (7)	7.3 × 105f
		P2	10		−
		P3	4		−
		P4	7		−
		P5	12		−
	GII3-11c1 (ori)	P1	5	7.5 × 105	+	4.5 × 106
		P2	7		+	5.3 × 106
		P3	10		+	ND
		P4	11		+	ND
		P5	2		+	ND
2	SP4 medium	P1	8		−
		P2	1			ND
		P3	5			ND
	GII3 (wild type)	P1	7	1.9 × 106	+	1.2 × 107
		P2	7		+
		P3	6		+
	GII3-9a2 (Δspi)	P1	7	2.9 × 106	−
		P2	4		−
		P3	11		+ (3)	1.4 × 107
		P4	5		−
		P5	9		−
	GII3-11c1 (ori)	P1	6	1.2 × 106	+	1 × 107
		P2	9		+	ND
		P3	9		+	9.5 × 106
		P4	9		+	ND
		P5	9		+	8.5 × 106

^aNumber of living insects at the end of the 2-week transmission period. All plants were initially subjected to infection by 12 injected insects.

^bAverage of four independent determinations, each from a group of five insects taken at the end of the transmission period.

^cNumbers in parentheses indicate the delay (in weeks) in symptom appearance compared to that for the control strain GII-3.

^dSpiroplasma titers were determined at 6 (experiment 1) or 7 (experiment 2) weeks posttransmission.

^eND, not done.

^fIn this plant, spiroplasma titers were 2.2×10² and 7.3×10⁵ CFU/g of midribs at 8 and 16 weeks posttransmission, respectively.