Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain ...Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain a deeper understanding of the genetic mechanism of lutein in marigold, a chromosome-scale assembly of the marigold(T. erecta V-01) genome was completed based on Illumina, PacBio, and Hi-C reads. The707.21-Mb assembled genome consisted of 35 834 annotated protein-coding genes, with 97.7% genomic integrity. We anchored 87.8% of the contigs(covering 621.20 Mb) to 12 pseudochromosomes, bringing the scaffold N50 length to 54.15 Mb. Phylogenetic analysis showed that marigold was closely related to the Asteraceae species bitter vine(Mikania micrantha) and sunflower(Helianthus annuus), all three of which originated in the Americas. Marigold diverged from the sunflower clade 23.57 million years ago(MYA) and from M. micrantha 19.59 MYA.Marigold has undergone three whole-genome duplication events, as well as a recent whole-genome duplication event(WGD-2) common to H.annuus and M. micrantha. Marigold gene families were significantly less expanded than those of M. micrantha or H. annuus, and the marigold genome contained significantly fewer interspersed repeats, which might account for its smaller genome. In addition, a range of candidate genes involved in the lutein biosynthetic pathway were identified. The high-quality reference genome obtained in this study provided a valuable genomic resource for studying the evolution of the Asteraceae family and for improving marigold breeding strategies.展开更多
Salt and drought limit the range of applications of perennial ryegrass(Lolium perenne L.), which is one of the important turf and forage grasses. Previous studies have suggested that pyrroline-5-carboxylate reductase(...Salt and drought limit the range of applications of perennial ryegrass(Lolium perenne L.), which is one of the important turf and forage grasses. Previous studies have suggested that pyrroline-5-carboxylate reductase(P5CR) might play a central role in proline accumulation in plants that are responsive to stresses. In the present study, the Lolium perenne L. pyrroline-5-carboxylate reductase(LpP 5CR) gene was cloned from leaves of the cultivar ‘Derby' using the RACE technique. The full-length LpP 5CR gene was 1 047 bp in length, which comprised an open reading frame(ORF) of 840 bp in size. Sequence alignment revealed that the putative Lp P5 CR had a 94.3% similarity to Ta P5 CR. q RT-PCR displayed that the mR NA levels of the LpP 5CR gene were almost the same as that in the roots, stems, and leaves of perennial ryegrass seedlings subjected to normal condition or NaC l treatment for 1 h. Moreover, the transcription level of LpP 5CR was up- or down- regulated with Na Cl, polyethylene glycol(PEG), cold, or abscisic acid(ABA) treatment for 3 to 48 h. In addition, confocal microscopy localized the GFP-Lp P5 CR fusion protein to the cytoplasm of onion epidermal cells. These findings suggest that LpP 5CR encodes a cytoplasmic P5 CR protein that plays an important role in the response of perennial ryegrass to various stresses.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 31572166, 31772344, 31871691 and 31972444)。
文摘Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain a deeper understanding of the genetic mechanism of lutein in marigold, a chromosome-scale assembly of the marigold(T. erecta V-01) genome was completed based on Illumina, PacBio, and Hi-C reads. The707.21-Mb assembled genome consisted of 35 834 annotated protein-coding genes, with 97.7% genomic integrity. We anchored 87.8% of the contigs(covering 621.20 Mb) to 12 pseudochromosomes, bringing the scaffold N50 length to 54.15 Mb. Phylogenetic analysis showed that marigold was closely related to the Asteraceae species bitter vine(Mikania micrantha) and sunflower(Helianthus annuus), all three of which originated in the Americas. Marigold diverged from the sunflower clade 23.57 million years ago(MYA) and from M. micrantha 19.59 MYA.Marigold has undergone three whole-genome duplication events, as well as a recent whole-genome duplication event(WGD-2) common to H.annuus and M. micrantha. Marigold gene families were significantly less expanded than those of M. micrantha or H. annuus, and the marigold genome contained significantly fewer interspersed repeats, which might account for its smaller genome. In addition, a range of candidate genes involved in the lutein biosynthetic pathway were identified. The high-quality reference genome obtained in this study provided a valuable genomic resource for studying the evolution of the Asteraceae family and for improving marigold breeding strategies.
基金The National High Technology Research and Development Program of China(Grant No.2011AA100209)Jilin Provincial Department of Education(Grant No.2013-23)supported this study
文摘Salt and drought limit the range of applications of perennial ryegrass(Lolium perenne L.), which is one of the important turf and forage grasses. Previous studies have suggested that pyrroline-5-carboxylate reductase(P5CR) might play a central role in proline accumulation in plants that are responsive to stresses. In the present study, the Lolium perenne L. pyrroline-5-carboxylate reductase(LpP 5CR) gene was cloned from leaves of the cultivar ‘Derby' using the RACE technique. The full-length LpP 5CR gene was 1 047 bp in length, which comprised an open reading frame(ORF) of 840 bp in size. Sequence alignment revealed that the putative Lp P5 CR had a 94.3% similarity to Ta P5 CR. q RT-PCR displayed that the mR NA levels of the LpP 5CR gene were almost the same as that in the roots, stems, and leaves of perennial ryegrass seedlings subjected to normal condition or NaC l treatment for 1 h. Moreover, the transcription level of LpP 5CR was up- or down- regulated with Na Cl, polyethylene glycol(PEG), cold, or abscisic acid(ABA) treatment for 3 to 48 h. In addition, confocal microscopy localized the GFP-Lp P5 CR fusion protein to the cytoplasm of onion epidermal cells. These findings suggest that LpP 5CR encodes a cytoplasmic P5 CR protein that plays an important role in the response of perennial ryegrass to various stresses.
