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Gene expression profiling offers a means of understanding pathogenesis in clubroot of crucifers caused by the biotrophic pathogen Plasmodiophora brassicae. In this study, a canola (Brassica napus) cultivar 45H29 was inoculated with P. brassicae pathotypes 5I (P5I) and 5X (P5X), and the pathogen:plant DNA biomass ratio in roots was determined at 7, 14, and 21 days after inoculation (dai) by quantitative PCR (qPCR) analysis. The P5X:plant biomass ratio increased across the time course, while the P5I:plant biomass ratio decreased. To investigate genes differentially expressed during the infection process, the expression of 205 P. brassicae genes encoding putative secreted proteins was analysed from the inoculated samples at 14 dai. One of the 205 genes was expressed at a higher level in P5X than in P5I, while 15 genes were expressed at a higher level in P5I than in P5X. Of these 16, 13 genes encoded proteins with high cysteine content, while three genes encoded proteins with an RXLR motif. The expression of the 16 genes was analysed further in the 7‐ and 21‐dai samples. No transcripts of the 16 genes were detected from either pathotype at 7 dai. In contrast, 11 genes were differentially expressed between the two pathotypes at 21 dai, with nine being more highly expressed in P5X and two in P5I. One gene showed homology to PbSUNK2 found in P. brassicae‐infected Arabidopsis thaliana root tissues. These 16 genes may offer important information to improve the current understanding of canola–P. brassicae interactions.

The planting of clubroot resistant (CR) canola (Brassica napus) is the most effective method to manage clubroot. Since 2013, many Plasmodiophora brassicae isolates capable of overcoming resistance have been detected, often in mixtures with avirulent isolates. To improve understanding of the effect of low concentrations of virulent isolates on host resistance, three CR canola cultivars (45H29, L135C, and L241C) were inoculated with pairs of isolates representing virulent/avirulent pathotypes (2*/2, 3*/3, and 5*/5) collected after or before the introduction of CR canola, respectively. Seven-day-old seedlings of each cultivar were incubated for 2 days in low concentrations (1 × 103 spores/ml) of the virulent isolates, followed by a second inoculation with a high concentration (1 × 107 spores/ml) of the avirulent isolates. Positive controls comprised seedlings inoculated with low concentrations of the virulent isolates followed by high concentrations of the virulent isolates (PC1) or only with high concentrations of virulent isolates (PC2). Negative controls comprised seedlings inoculated only with high concentrations of the avirulent isolates (NC1) or only with low concentrations of the virulent isolates (NC2). Clubroot severity was significantly higher in all nine experimental treatments (low virulent plus high avirulent) than in the negative control NC1 (high avirulent) but was lower in the experimental treatments than in the positive controls (PC1 and PC2). Low concentrations of virulent isolates alone (NC2) caused moderate clubroot. Disease severity correlated well with P. brassicae biomass in canola as determined by quantitative PCR analysis 28 to 35 days after inoculation. This study revealed that low concentrations of virulent isolates compromised canola resistance for infection by avirulent isolates.

The size of the human eye opening and closing plays a certain role in the human-computer interaction platform, such as the PERCLOS parameter commonly used in driver fatigue detection. Considering that the image in the actual application scene is often accompanied by distance, blur, etc., this paper proposes an algorithm based on BiseNet and Vgg methods which can segment the pupil and iris while outputting the realtime opening ratio of the eye.

This study was conducted with the objective of finding genetic marker(s) to differentiate pathotypes of the clubroot pathogen Plasmodiophora brassicae. Ideally, such markers should be used as a diagnostic tool to identify or predict certain pathotypes. By using PCR with gene-specific primers, 117 non-housekeeping P. brassicae genes were investigated for their presence/absence in isolates representing pathotypes 2, 3, 5, 6 or 8 (Williams’ system), and in new strains of the pathogen recently identified from Alberta, Canada, which are highly virulent on clubroot resistant canola (Brassica napus) cultivars. One gene, named Cr811, was present in isolates of pathotype 5 and in a new strain of P. brassicae that also is classified as pathotype 5 on the system of Williams, but causes severe clubroot on resistant canola. Three additional newly identified virulent populations, similar to pathotype 3, also were tested and found to carry Cr811. In contrast, the Cr811 gene was absent in all isolates representing the original pathotypes 2, 3, 6 and 8. Quantitative real-time PCR analysis indicated greater copy numbers of Cr811 in the new virulent pathotype 3-like and pathotype 5-like populations versus the original pathotype 5, indicating a potential method to identify new pathotypes of P. brassicae before the breakdown of resistance could be detected in a canola crop. The association of Cr811 with infection by P. brassicae of previously resistant canola cultivars, as revealed by qPCR analysis, suggests that Cr811 plays an important role in the interaction between host resistance and P. brassicae pathogenicity.