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Rapeseed (Brassica napus) is a major edible oilseed crop consumed worldwide. However, its yield is seriously affected by infection from the broad-spectrum non-obligate pathogen Sclerotinia sclerotiorum due to a lack of highly resistant germplasm. Here, we identified a Sclerotinia-resistant and light-dependent lesion mimic mutant from an ethyl methanesulfonate-mutagenized population of the rapeseed inbred Zhongshuang 11 (ZS11) named lesion mimic mutant 1 (lmm1). The phenotype of lmm1 is controlled by a single recessive gene, named LESION MIMIC MUTANT 1 (LMM1), which mapped onto chromosome C04 by bulked segregant analysis within a 2.71-Mb interval. Histochemical analysis indicated that H2O2 strongly accumulated and cell death occurred around the lesion mimic spots. Among 877 differentially expressed genes (DEGs) between ZS11 and lmm1 leaves, 188 DEGs were enriched in the defense response, including 95 DEGs involved in systemic acquired resistance, which is consistent with the higher salicylic acid levels in lmm1. Combining bulked segregant analysis and transcriptome analysis, we identified a significantly up-regulated gene, BnaC4.PR2, which encodes β-1,3-glucanase, as the candidate gene for LMM1. Overexpression of BnaC4.PR2 may induce a reactive oxygen species burst to trigger partial cell death and systemic acquired resistance. Our study provides a new genetic resource for S. sclerotiorum resistance as well as new insights into disease resistance breeding in B. napus., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Petal size determines the value of ornamental plants, and thus their economic value. However, the molecular mechanisms controlling petal size remain unclear in most non-model species. To identify quantitative trait loci and candidate genes controlling petal size in rapeseed (Brassica napus), we performed a genome-wide association study (GWAS) using data from 588 accessions over three consecutive years. We detected 16 significant single nucleotide polymorphisms (SNPs) associated with petal size, with the most significant SNPs located on chromosomes A05 and C06. A combination of GWAS and transcriptomic sequencing based on two accessions with contrasting differences in petal size identified 52 differentially expressed genes (DEGs) that may control petal size variation in rapeseed. In particular, the rapeseed gene BnaA05.RAP2.2, homologous to Arabidopsis RAP2.2, may be critical to the negative control of petal size through the ethylene signaling pathway. In addition, a comparison of petal epidermal cells indicated that petal size differences between the two contrasting accessions were determined mainly by differences in cell number. Finally, we propose a model for the control of petal size in rapeseed through ethylene and cytokinin signaling pathways. Our results provide insights into the genetic mechanisms regulating petal size in flowering plants., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Real-time quantitative polymerase chain reaction (qPCR) is one of the most important methods for analyzing the expression patterns of target genes. However, successful qPCR experiments rely heavily on the use of high-quality primers. Various qPCR primer databases have been developed to address this issue, but these databases target only a few important organisms. Here, we developed the qPrimerDB database, founded on an automatic gene-specific qPCR primer design and thermodynamics-based validation workflow. The qPrimerDB database is the most comprehensive qPCR primer database available to date, with a web front-end providing gene-specific and pre-computed primer pairs across 147 important organisms, including human, mouse, zebrafish, yeast, thale cress, rice and maize. In this database, we provide 3331426 of the best primer pairs for each gene, based on primer pair coverage, as well as 47760359 alternative gene-specific primer pairs, which can be conveniently batch downloaded. The specificity and efficiency was validated for qPCR primer pairs for 66 randomly selected genes, in six different organisms, through qPCR assays and gel electrophoresis. The qPrimerDB database represents a valuable, timesaving resource for gene expression analysis. This resource, which will be routinely updated, is publically accessible at http://biodb.swu.edu.cn/qprimerdb., (© The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.)