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1.
Gene ; 712: 143962, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31288057

RESUMO

Veratrum nigrum is protected plant of Melanthiaceae family, able to synthetize unique steroidal alkaloids important for pharmacy. Transcriptomes from leaves, stems and rhizomes of in vitro maintained V. nigrum plants were sequenced and annotated for genes and markers discovery. Sequencing of samples derived from the different organs resulted in a total of 108,511 contigs with a mean length of 596 bp. Transcripts derived from leaf and stalk were annotated at 28%, and 38% in Nr nucleotide database, respectively. The sequencing revealed 949 unigenes related with lipid metabolism, including 73 transcripts involved in steroids and genus-specific steroid alkaloids biosynthesis. Additionally, 3203 candidate SSRs markers we identified in unigenes with average density of one SSR locus every 6.2 kb sequence. Unraveling of biochemical machinery of the pathway responsible for steroidal alkaloids will open possibility to design and optimize biotechnological process. The transcriptomic data provide valuable resources for biochemical, molecular genetics, comparative transcriptomics, functional genomics, ecological and evolutionary studies of V. nigrum.


Assuntos
Alcaloides/biossíntese , Regulação da Expressão Gênica de Plantas , Esteroides/biossíntese , Transcriptoma , Veratrum/metabolismo , Mapeamento de Sequências Contíguas , DNA Complementar/metabolismo , Biblioteca Gênica , Ontologia Genética , Marcadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Repetições de Microssatélites , Anotação de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Análise de Sequência de RNA
2.
J Plant Physiol ; 231: 415-433, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30412849

RESUMO

With unfavourable climate changes and an increasing global population, there is a great need for more productive and stress-tolerant crops. As traditional methods of crop improvement have probably reached their limits, a further increase in the productivity of crops is expected to be possible using genetic engineering. The number of potential genes and metabolic pathways, which when genetically modified could result in improved photosynthesis and biomass production, is multiple. Photosynthesis, as the only source of carbon required for the growth and development of plants, attracts much attention is this respect, especially the question concerning how to improve CO2 fixation and limit photorespiration. The most promising direction for increasing CO2 assimilation is implementating carbon concentrating mechanisms found in cyanobacteria and algae into crop plants, while hitherto performed experiments on improving the CO2 fixation versus oxygenation reaction catalyzed by Rubisco are less encouraging. On the other hand, introducing the C4 pathway into C3 plants is a very difficult challenge. Among other points of interest for increased biomass production is engineering of metabolic regulation, certain proteins, nucleic acids or phytohormones. In this respect, enhanced sucrose synthesis, assimilate translocation to sink organs and starch synthesis is crucial, as is genetic engineering of the phytohormone metabolism. As abiotic stress tolerance is one of the key factors determining crop productivity, extensive studies are being undertaken to develop transgenic plants characterized by elevated stress resistance. This can be accomplished due to elevated synthesis of antioxidants, osmoprotectants and protective proteins. Among other promising targets for the genetic engineering of plants with elevated stress resistance are transcription factors that play a key role in abiotic stress responses of plants. In this review, most of the approaches to improving the productivity of plants that are potentially promising and have already been undertaken are described. In addition to this, the limitations faced, potential challenges and possibilities regarding future research are discussed.


Assuntos
Produção Agrícola/métodos , Fotossíntese , Desenvolvimento Vegetal , Engenharia Genética , Fotossíntese/genética , Desenvolvimento Vegetal/genética , Fenômenos Fisiológicos Vegetais/genética , Plantas/genética , Plantas Geneticamente Modificadas , Estresse Fisiológico/genética
3.
J Plant Physiol ; 229: 32-40, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30031159

RESUMO

In this review, we summarize the results of experiments that lead to altered levels of phytohormones in transgenic plants to improve plant productivity. The available data indicate that manipulating the level of phytohormones might also be a promising way to enhance the environmental stress tolerance of crop plants. In the regulation of the level of phytohormones, both biosynthesis and their catabolism pathways can be targeted for engineering purposes. Moreover, the signaling pathways of phytohormones should explored in this respect. In genetic modifications, conditional promoters must be developed to avoid undesired effects on growth. In order to find a practical application, the effects of genetic modifications should be further verified under field conditions and over a longer time scale.


Assuntos
Reguladores de Crescimento de Planta/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia
4.
Plant J ; 2018 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-29901834

RESUMO

Prenylquinols (tocochromanols and plastoquinols) serve as efficient physical and chemical quenchers of singlet oxygen (1 O2 ) formed during high light stress in higher plants. Although quenching of 1 O2 by prenylquinols has been previously studied, direct evidence for chemical quenching of 1 O2 by plastoquinols and their oxidation products is limited in vivo. In the present study, the role of plastoquinol-9 (PQH2 -9) in chemical quenching of 1 O2 was studied in Arabidopsis thaliana lines overexpressing the SOLANESYL DIPHOSPHATE SYNTHASE 1 gene (SPS1oex) involved in PQH2 -9 and plastochromanol-8 biosynthesis. In this work, direct evidence for chemical quenching of 1 O2 by plastoquinols and their oxidation products is presented, which is obtained by microscopic techniques in vivo. Chemical quenching of 1 O2 was associated with consumption of PQH2 -9 and formation of its various oxidized forms. Oxidation of PQH2 -9 by 1 O2 leads to plastoquinone-9 (PQ-9), which is subsequently oxidized to hydroxyplastoquinone-9 [PQ(OH)-9]. We provide here evidence that oxidation of PQ(OH)-9 by 1 O2 results in the formation of trihydroxyplastoquinone-9 [PQ(OH)3 -9]. It is concluded here that PQH2 -9 serves as an efficient 1 O2 chemical quencher in Arabidopsis, and PQ(OH)3 -9 can be considered as a natural product of 1 O2 reaction with PQ(OH)-9. The understanding of the mechanisms underlying 1 O2 chemical quenching provides information on the role of plastoquinols and their oxidation products in the response of plants to photooxidative stress.

5.
Genomics ; 2017 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-29107013

RESUMO

Changes in fenugreek transcriptome related to enhanced production of steroids were induced by methyl jasmonate, cholesterol and squalene, and recorded using RNA-seq. A total of 112,850 unigenes were obtained after de novo assembling of next generation sequencing data, and used for functional annotations. In steroidal saponins pathway, transcripts involved in mevalonate, terpenoid backbone and plant sterol synthesis were annotated. Overexpression of several transcripts from phytosterol biosynthesis pathway was confirmed by quantitative RT-PCR. In diosgenin biosynthesis pathway, fatty acid ω-hydroxylase (CYP86A2) and steroid 22-alpha-hydroxylase (CYP90B1) genes were annotated in all induced transcriptomes. Moreover, direct sequencing confirmed increased levels of CYP90B1, unspecific monooxygenase and 26-hydroxylase genes in plants with elevated level of diosgenin. New unigenes corresponding to enzymes involved in biosynthesis of diosgenin from cycloartenol via cholesterol were obtained and the role of CYP72A family in steroidal saponin biosynthesis was proposed. Additional support for biosynthetic pathway from cycloartenol to diosgenin was provided.

6.
Planta ; 245(5): 977-991, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28161815

RESUMO

MAIN CONCLUSION: Representational difference analysis of cDNA was performed and differential products were sequenced and annotated. Candidate genes involved in biosynthesis of diosgenin in fenugreek were identified. Detailed mechanism of diosgenin synthesis was proposed. Fenugreek (Trigonella foenum-graecum L.) is a valuable medicinal and crop plant. It belongs to Fabaceae family and has a unique potential to synthesize valuable steroidal saponins, e.g., diosgenin. Elicitation (methyl jasmonate) and precursor feeding (cholesterol and squalene) were used to enhance the content of sterols and steroidal sapogenins in in vitro grown plants for representational difference analysis of cDNA (cDNA-RDA). To identify candidate genes involved in diosgenin biosynthesis, differential, factor-specific libraries were subject to the next-generation sequencing. Approximately 9.9 million reads were obtained, trimmed, and assembled into 31,491 unigenes with an average length of 291 bp. Then, functional annotation and gene ontogeny enrichment analysis was performed by aligning all-unigenes with public databases. Within the transcripts related to sterol and steroidal saponin biosynthesis, we discovered novel candidate genes of diosgenin biosynthesis and validated their expression using quantitative RT-PCR analysis. Based on these findings, we supported the idea that diosgenin is biosynthesized from cycloartenol via cholesterol. This is the first report on the next-generation sequencing of cDNA-RDA products. Analysis of the transcriptomes enriched in low copy sequences contributed substantially to our understanding of the biochemical pathways of steroid synthesis in fenugreek.


Assuntos
Acetatos/metabolismo , Ciclopentanos/metabolismo , Diosgenina/metabolismo , Oxilipinas/metabolismo , Fitosteróis/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Transcriptoma , Trigonella/genética , DNA Complementar/genética , Sequenciamento de Nucleotídeos em Larga Escala , Análise de Sequência de DNA , Trigonella/metabolismo
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