The genetic basis of seed germination and seedling vigor is largely unknown in Brassica species. We performed a study to evaluate the genetic basis of these important traits in a B. rapa doubled haploid population from a cross of a yellow-seeded oil-type yellow sarson and a black-seeded vegetable-type pak choi. We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits. QTLs for multiple traits co-localized and we identified eight hotspots for quantitative trait loci (QTL) of seed weight, seed germination, and root and shoot lengths. A QTL hotspot for seed germination on A02 mapped at the B. rapa Flowering Locus C (BrFLC2). Another hotspot on A05 with salt stress specific QTLs co-located with the B. rapa Fatty acid desaturase 2 (BrFAD2) locus. Epistatic interactions were observed between QTL hotspots for seed germination on A02 and A10 and with a salt tolerance QTL on A05. These results contribute to the understanding of the genetics of seed quality and seeding vigor in B. rapa and can offer tools for Brassica breeding.

Clubroot disease, which is caused by Plasmodiophora brassicae Wor., a soil-borne microorganism, is one of the most severe diseases of Brassicacrops. Combining of two and more dominant resistance...

Black rot disease, caused by Xanthomonas campestris pv. campestris (Xcc), results in significant yield losses in Brassica oleracea crops worldwide. To find black rot disease-resistant cabbage lines, we carried out pathogenicity assays using the scissor-clipping method in 94 different B. oleracea lines. By comparing the lesion areas, we selected a relatively resistant line, Black rot Resistance 155 (BR155), and a highly susceptible line, SC31. We compared the two cabbage lines for the Xcc-induced expression pattern of 13 defense-related genes. Among them, the Xcc-induced expression level of PR1 and antioxidant-related genes (SOD, POD, APX, Trx H, and CHI) were more than two times higher in BR155 than SC31. Nitroblue tetrazolium (NBT) and diaminobenzidine tetrahydrochloride (DAB) staining analysis showed that BR155 accumulated less Xcc-induced reactive oxygen species (ROS) than did SC31. In addition, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays showed that BR155 had higher antioxidant activity than SC31. This study, focused on the defense responses of cabbage during the early biotrophic stage of infection, indicated that Xcc-induced ROS might play a role in black rot disease development. We suggest that non-enzymatic antioxidants are important, particularly in the early defense mechanisms of cabbage against Xcc.

Morphogenetic factors (MTFs) are specialized plant genes and transcription factors that play pivotal roles in embryogenesis and organogenesis. This review focuses on their functions in plant development regulation and their applications in plant biotechnology and modern breeding. Common challenges in transformation and regeneration were discussed, along with successful case studies demonstrating improved regeneration capacity and transgene stability in rice (Oryza sativa), soybean (Glycine max), rapeseed (Brassica napus), tomato (Solanum lycopersicum) and other less common crops and plant model organisms. These improvements were achieved through the utilization of key developmental MTFs such as WUCHEL, BABY BOOM, GRF-GIF, etc. The principles of designing genetic constructs with MTFs are explored, including promoter selection and regulatory elements, as well as their synergistic effects with phytohormones like auxins and cytokinins for optimizing in vitro morphogenesis. Current limitations in MTF expression and strategies to overcome them are analyzed. The article highlights recent advances, including MTFs potential for developing stress-resistant, high-yielding cultivars. Key discussion points include the discovery of novel morphogens, their application to recalcitrant species, and prospects for expanding the range of easily transformable and regenerable crops. Future directions involve developing universal transformation protocols and integrating morphogens with precision genome editing technologies, offering new opportunities for agriculture and global food security.