Table 1.

Effect of LmStuA silencing on growth, conidia production, fertility and pathogenicity of L eptosphaeria maculans

Isolate	Relative expression level (%)a	Radial growth (mm)b	Conidia/mLc	Sexual fertility (number of perithecia)d	Pathogenicity on cotyledonse
Wild‐type
v23.1.3	100	51.6 ± 0.7	1.97 × 108	Yes (>5)	3.54 ± 0.72
Transformants
s.LmStuA‐21	21	43 ± 1.8f	2.17 × 107	No (0)	1 ± 0.00f
s.LmStuA‐49	49	31 ± 0.75f	4.33 × 107	No (<5)	1 ± 0.00f
s.LmStuA‐64	64	51.3 ± 0.6	2.83 × 107	Yes (>5)	1 ± 0.00f

^a LmStuA expression was assessed by quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR) with RNA isolated from mycelial culture. Expression is relative to the elongation factor 1α (EF1α) expression level and to the expression of LmStuA in the wild‐type isolate v23.1.3 (2^{−ΔΔ C t} method).

^bRadial growth (mm) at 8 days post‐inoculation on V8 agar plates.

^cConidiation (number of conidia/mL). Conidia were collected from five plates per transformant.

^dFertility was measured by crossing v23.1.3 and the selected silenced LmStuA (s.LmStuA) transformants with the compatible isolate v23.1.2. Crosses were considered as fertile if more than five perithecia ejecting ascospores were produced per plate.

^ePathogenicity was assayed 14 days after inoculation on the susceptible cultivar Westar of Brassica napus. Results are expressed as the mean score using the IMASCORE rating scale, comprising six infection classes (ICs), where IC1–IC3 correspond to resistance and IC4–IC6 to susceptibility (Balesdent et al., 2006).

^f P < 0.05. Disease scores and radial growth of each isolate were analysed using analysis of variance (ANOVA). Transformants were compared with v23.1.3 by a Dunnett multiple comparison test (α = 0.05). All statistical analyses were performed using XLStat 7.5 software.