摘要:
Brassica juncea, a worldwide cultivated crop plant, produces seeds of different colors. Seed pigmentation is due to the deposition in endothelial cells of proanthocyanidins (PAs), end products from a branch of flavonoid biosynthetic pathway. To elucidate the gene regulatory network of seed pigmentation in B. juncea, transcriptomes in seed coat of a yellow-seeded inbred line and its brown-seeded near- isogenic line were sequenced using the next-generation sequencing platform Illumina/Solexa and de novo assembled. Over 116 million high-quality reads were assembled into 69,605 unigenes, of which about 71.5% (49,758 unigenes) were aligned to Nr protein database with a cut-off E-value of 10(-5). RPKM analysis showed that the brown-seeded testa up-regulated 802 unigenes and down-regulated 502 unigenes as compared to the yellow-seeded one. Biological pathway analysis revealed the involvement of forty six unigenes in flavonoid biosynthesis. The unigenes encoding dihydroflavonol reductase (DFR), leucoantho-cyanidin dioxygenase (LDOX) and anthocyanidin reductase (ANR) for late flavonoid biosynthesis were not expressed at all or at a very low level in the yellow-seeded testa, which implied that these genes for PAs biosynthesis be associated with seed color of B. juncea, as confirmed by qRT-PCR analysis of these genes. To our knowledge, it is the first time to sequence the transcriptome of seed coat in Brassica juncea. The unigene sequences obtained in this study will not only lay the foundations for insight into the molecular mechanisms underlying seed pigmentation in B. juncea, but also provide the basis for further genomics research on this species or its allies.
摘要:
An increase in oleic acid (C18:1) content is a desirable trait. Despite the critical roles of the two desaturases, FAD2 and FAD3, in the control of fatty acid desaturation, a dispute remains over whether inactivation of their genes alone is sufficient enough to generate the high-oleic trait. To address this question, we employed microarray technology to investigate the difference in gene expression profile between two different Brassica napus strains with high-C18:1 (71.71%) and low-C18:1 (55.6%) contents, respectively. Our study revealed 562 differentially expressed genes, of which 194 genes were up-regulated and 368 down-regulated. Based on the Gene Ontology classification, these genes were classified into 23 functional categories. Three of the up-regulated genes represent B. napus homologs of Arabidopsis genes encoding a cytosolic isoform of pyruvate kinase (AT3G55810), Δ9 acyl-lipid desaturase (AT1G06080, ADS1) and fatty acyl-ACP thioesterase B (AT1G08510), respectively. Conversely, the homologs of two Arabidopsis sequences encoding Δ9 acyl-lipid desaturase (AT2G31360, ADS2) and FAD3 desaturase (AT2G29980) were down-regulated in the high-oleic acid strain. Furthermore, 60 differentially expressed genes were classified as associated with relevant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Collectively, our results suggest that expressing the high-oleic acid trait may require a coordinated regulation of diverse regulatory and metabolic gene networks in addition to inactivation of the FAD2 and FAD3 genes in the oilseed. A set of the differentially expressed genes identified in this study will facilitate our efforts to tap the germplasms with the potential to express the high-oleic acid trait.
摘要:
With 4 figures and 2 tables Abstract The yellow seed is a desirable trait in oilseed Brassica species. However, seed coat colour cannot be observed until the maturation of the seed. Identification of seed coat colour at early seed development will allow for the early detection of yellow‐seeded individual plants in the segregating populations at the same generation and thus speed up yellow‐seeded rapeseed breeding programme. Colour of seed coats from Brassica juncea and Brassica napus can precisely be determined as early as 15 days after pollination by staining with 0.5% vanillin–HCl solution for 5 min, which is shown to be simple, rapid and reliable. Flowering duration of an individual plant usually lasts for approximately 25–35 days in Brassica species and so the seed coat colour of an individual plant can be determined 10–20 days before the end of its flowering. Through this technique, breeding for the yellow‐seeded trait can now be advanced one generation earlier by vanillin staining than by conventional visual observation of testa colour of mature Brassica seeds.
作者:
Li Wen;Ying Chen;Jiabin Shu;Tailong Tan;Qiuping Zhang;...
期刊:
植物科学学报,2012年30(z1):15-16 ISSN:2095-0837
作者机构:
Institute of Oilseed Crops, Hunan Agricultural University, Changsha 410128, China;Chemical and Biological Engineering College, Changsha University of Science and Technology, Changsha 410114, China