Fig. 5

Effect of GPCR inhibitor treatment on the growth, development of rapeseed plants, resting spore germination rate and root hair infection rate of Plasmodiophora brassicae. a Growth and development status of rape plants treated with GPCR inhibitor (right). Mock (DMSO) treatment served as control (left). The pictures were taken at 28 days after treatment. Bar = 1.5 cm. b At 28 days after treatment, the roots of mock- and inhibitor-treated plants were harvested. The expression levels of GPA1, AGB1, and AGG1 (downstream genes of GPCRs) in Brassica napus with mock and inhibitor treatment were quantified by qPCR. The actin gene of B. napus was used as control to normalize the expression level. Data represent the means and standard deviations. The expression level of mock-treated group was set as 1.0. Statistically significant difference of data between mock and inhibitor treated groups was compared, and the same letter in the graph indicates no significant differences at the level of P < 0.05. c, d Resting spore germination rate and root hair infection rate of P. brassicae were compared between H₂O_, mock and inhibitor treated groups. After 4 days, the treated spores were stained with orcein (Sigma-Aldrich Canada). The germination rate of spore was counted under microscope. At 7 dpi, the roots of rapeseed plant were stained with Trypan Blue, and then the root hair infection rate was counted with microscopic examination. The graphic data represent the means and standard deviations from three biological replicates. At the level of P < 0.05, statistically significant differences of data between H₂O_, mock and inhibitor treated groups were compared, different letters in the graph indicate statistically significant differences according to Student’s t test