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[学术文献 ] Safety evaluation of FAD2 RNAi transgenic Brassica napus L. based on microbial diversity and metabonomic analysis 进入全文
Front Plant Sci
Oleic acid desaturase (FAD2) is the key enzyme that produces polyunsaturated fatty acids in rapeseed (Brassica napus L), which is one of the main oil crops. RNA interference (RNAi) is an emerging technique that provides new opportunities for the generation of new traits in plants. To increase oleic acid content and reduce linoleic and linolenic acid content in rapeseed, we constructed an ihpRNA plant expression vector of the FAD2 gene and obtained transgenic plants for multiple generations by stable inheritance. In this study, third-generation transgenic plants (T3), seventh-generation transgenic plants (T7), and wild-type plants (WT) were used. The differences in microbial community diversity between transgenic plants and wild-type plants and the up- and downregulation of rhizosphere metabolite contents were investigated. In conclusion, the results showed that the soil microbial community structure was stable, the general microbial community structure was not changed by the transgenic rhizosphere exudates, and no significant harmful root exudate of transgenic rapeseed on the environment was found through the microbial community and metabolomics analysis. This work may provide an understanding of the impact of RNAi on plant metabolites and a safety evaluation method for transgenic plants and a reference for rapeseed breeding.
[学术文献 ] Integrating GWAS, linkage mapping and gene expression analyses reveal the genetic control of first branch height in Brassica napus L 进入全文
Front Plant Sci
Rapeseed (Brassica napus L.) is a crucial oil crop cultivated worldwide. First branch height, an essential component of rapeseed plant architecture, has an important effect on yield and mechanized harvesting; however, the underlying genetic mechanism remains unclear. In this study, based on the 60K single nucleotide polymorphism array and a recombinant inbred lines population derived from M083 and 888-5, a total of 19 QTLs were detected in five environments, distributed on linkage groups A02, A09, A10, C06, and C07, which explained phenotypic variation ranging from 4.87 to 29.87%. Furthermore, 26 significant SNPs were discovered on Chr.A02 by genome-wide association study in a diversity panel of 324 re-sequencing accessions. The major QTL of the first branch height trait was co-located on Chr.A02 by integrating linkage mapping and association mapping. Eleven candidate genes were screened via allelic variation analysis, inter-subgenomic synteny analysis, and differential expression of genes in parental shoot apical meristem tissues. Among these genes, BnaA02g13010D, which encodes a TCP transcription factor, was confirmed as the target gene according to gene function annotation, haplotype analysis, and full-length gene sequencing, which revealed that TATA insertion/deletion in the promoter region was closely linked to significantly phenotypic differences BnaA02.TCP1M083 overexpression resulted in decreased branch height and increased branch number in Arabidopsis. These results provide a genetic basis for first branch height and the ideal architecture of B. napus.
[学术文献 ] Ammonia borane positively regulates cold tolerance in Brassica napus via hydrogen sulfide signaling 进入全文
BMC Plant Biology
Cold stress adversely influences rapeseeds (Brassica napus L.) growth and yield during winter and spring seasons. Hydrogen (H2) is a potential gasotransmitter that is used to enhance tolerance against abiotic stress, including cold stress. However, convenience and stability are two crucial limiting factors upon the application of H2 in field agriculture. To explore the application of H2 in field, here we evaluated the role of ammonia borane (AB), a new candidate for a H2 donor produced by industrial chemical production, in plant cold tolerance.The application with AB could obviously alleviate the inhibition of rapeseed seedling growth and reduce the oxidative damage caused by cold stress. The above physiological process was closely related to the increased antioxidant enzyme system and reestablished redox homeostasis. Importantly, cold stress-triggered endogenous H2S biosynthesis was further stimulated by AB addition. The removal or inhibition of H2S synthesis significantly abolished plant tolerance against cold stress elicited by AB. Further field experiments demonstrated that the phenotypic and physiological performances of rapeseed plants after challenged with cold stress in the winter and early spring seasons were significantly improved by administration with AB. Particularly, the most studied cold-stress response pathway, the ICE1-CBF-COR transcriptional cascade, was significantly up-regulated either. Overall, this study clearly observed the evidence that AB-increased tolerance against cold stress could be suitable for using in field agriculture by stimulation of H2S signaling.
[学术文献 ] Induction of Male Sterility by Targeted Mutation of a Restorer-of-Fertility Gene with CRISPR/Cas9-Mediated Genome Editing in Brassica napus L. 进入全文
Plants
Brassica napus L. (canola, oil seed rape) is one of the world’s most important oil seed crops. In the last four decades, the discovery of cytoplasmic male-sterility (CMS) systems and the restoration of fertility (Rf) genes in B. napus has improved the crop traits by heterosis. The homologs of Rf genes, known as the restoration of fertility-like (RFL) genes, have also gained importance because of their similarities with Rf genes. Such as a high non-synonymous/synonymous codon replacement ratio (dN/dS), autonomous gene duplications, and a possible engrossment in fertility restoration. B. napus contains 53 RFL genes on chromosomes A9 and C8. Our research aims to study the function of BnaRFL11 in fertility restoration using the CRISPR/Cas9 genome editing technique. A total of 88/108 (81.48%) T0 lines, and for T1, 110/145 (75%) lines carried T-DNA insertions. Stable mutations were detected in the T0 and T1 generations, with an average allelic mutation transmission rate of 81%. We used CRISPR-P software to detect off-target 50 plants sequenced from the T0 generation that showed no off-target mutation, signifying that if the designed sgRNA is specific for the target, the off-target effects are negligible. We also concluded that the mutagenic competence of the designed sgRNAs mediated by U6-26 and U6-29 ranged widely from 31% to 96%. The phenotypic analysis of bnarfl11 revealed defects in the floral structure, leaf size, branch number, and seed production. We discovered a significant difference between the sterile line and fertile line flower development after using a stereomicroscope and scanning electron microscope. The pollen visibility test showed that the pollen grain had utterly degenerated. The cytological observations of homozygous mutant plants showed an anther abortion stage similar to nap-CMS, with a Orf222, Orf139, Ap3, and nad5c gene upregulation. The bnarfl11 shows vegetative defects, including fewer branches and a reduced leaf size, suggesting that PPR-encoding genes are essential for the plants’ vegetative and reproductive growth. Our results demonstrated that BnaRFL11 has a possible role in fertility restoration. The current study’s findings suggest that CRISPR/Cas9 mutations may divulge the functions of genes in polyploid species and provide agronomically desirable traits through a targeted mutation.
[学术文献 ] Evaluation of Indian Mustard Genotypes for White Rust Resistance Using BjuWRR1Gene and Their Phenotypic Performance 进入全文
Agronomy
The present investigation was carried out to identify the potential donors of resistant gene(s)/the source of white rust disease in B. juncea using 30 genotypes, including locally adapted accessions and advanced breeding lines. Out of 30 genotypes, ten lines viz. Bio-YSR, CAULC-1, CAULC-2, CAULC-3, CAULC-4, CAURM-2, CAULR-7, CAURM-4, CAURM 4-1, and CAURM 4-2 exhibited a lower PDI value (lesser than mean 10.83) with a superior agronomic performance related with the disease. The evaluation of these ten genotypes for the presence of the BjuWRR1 gene using a gene-based marker depicted the presence of the functional allele of the BjuWRR1 gene in the five genotypes viz., Bio-YSR, CAULC-1, CAULC-3, CAURM 4-1 and CAURM 4-2. When compared with the sequenced amplicon of these genotypes, it is found to be identical with that of an east European Brassica juncea line, Donskaja-IV, the completely resistant genotype against various isolates of Albugo candida. The findings from the present study suggested that besides Bio-YSR, the local lines of Manipur CAULC-1 (Local Yella of Potshangbam) and CAULC-3 (Local Yella of Kakching Lamjao) can be used as the potential white rust resistance sources/donors in disease resistance breeding programmes for the development of elite B. juncea cultivars in the future. In addition to the local lines, two improved advanced lines, viz. CAURM 4-1 and CAURM 4-2, obtained from a hybridization programme, may be further evaluated for releasing resistant varieties against white rust.
[学术文献 ] Sinapis genomes provide insights into whole-genome triplication and divergence patterns within tribe Brassiceae 进入全文
The Plant Journal
Sinapis alba and Sinapis arvensis are mustard crops within the Brassiceae tribe of the Brassicaceae family, and represent an important genetic resource for crop improvement. We performed the de novo assembly of Brassica nigra, S. alba, and S. arvensis, and conducted comparative genomics to investigate the pattern of genomic evolution since an ancient whole-genome triplication event. Both Sinapis species retained evidence of the Brassiceae whole-genome triplication approximately 20.5 million years ago (Mya), with subgenome dominance observed in gene density, gene expression, and selective constraint. While S. alba diverged from the ancestor of Brassica and Raphanus at approximately 12.5 Mya, the divergence time of S. arvensis and B. nigra was approximately 6.5 Mya. S. arvensis and B. nigra had greater collinearity compared with their relationship to either Brassica rapa or Brassica oleracea. Two chromosomes of S. alba (Sal03 and Sal08) were completely collinear with two ancestral chromosomes proposed in the Ancestral Crucifer Karyotype (ACK) genomic block model, the first time this has been observed in the Brassiceae. These results are consistent with S. alba representing a relatively ancient lineage of the species evolved from the common ancestor of tribe Brassiceae, and suggest that the phylogeny of the Brassica and Sinapis genera requires some revision. Our study provides new insights into the genome evolution and phylogenetic relationships of Brassiceae and provides genomic information for genetic improvement of these plants.
