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1.
Plant Sci ; 289: 110251, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31623789

RESUMO

Cytokinin Response Factors (CRFs) are a family of transcription factors which make up a side branch of the classical cytokinin two-component signaling pathway. CRFs were originally identified and have been primarily studied in Arabidopsis thaliana, although orthologs have be found throughout all land plants. Research into the evolution of CRFs as sub-group members of the larger APETALA2/Ethylene Response Factor (AP2/ERF) family has yielded interesting and useful insights related to the functional roles of CRFs in plants. Recent studies of CRFs suggest that these transcription factors are a lot more than just a group of cytokinin related genes and play important roles in both plant development and environmental stress response. This review focuses on recent advances in understanding the roles of CRFs beyond cytokinin, in reproductive development and abiotic stress response, as well as to other environmental cues.


Assuntos
Fenômenos Fisiológicos Vegetais/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Citocininas/metabolismo , Proteínas de Plantas/metabolismo , Reprodução/genética , Estresse Fisiológico/genética , Fatores de Transcrição/metabolismo
2.
BMC Plant Biol ; 19(1): 421, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31610789

RESUMO

BACKGROUND: Precise regulation of gene expression is indispensable for the proper functioning of organisms in both optimal and challenging conditions. The most commonly known regulative mechanisms include the modulation of transcription, translation and adjustment of the transcript, and protein half-life. New players have recently emerged in the arena of gene expression regulators - chemical modifications of mRNAs. MAIN TEXT: The latest studies show that modified ribonucleotides affect transcript splicing, localization, secondary structures, interaction with other molecules and translation efficiency. Thus far, attention has been focused mostly on the most widespread mRNA modification - adenosine methylation at the N6 position (m6A). However, initial reports on the formation and possible functions of other modified ribonucleotides, such as cytosine methylated at the 5' position (m5C), 8-hydroxyguanosine (8-OHG) and 8-nitroguanosine (8-NO2G), have started to appear in the literature. Additionally, some reports indicate that pseudouridine (Ψ) is present in mRNAs and might perform important regulatory functions in eukaryotic cells. The present review summarizes current knowledge regarding the above-mentioned modified ribonucleotides (m6A, m5C, 8-OHG, 8-NO2G) in transcripts across various plant species, including Arabidopsis, rice, sunflower, wheat, soybean and potato. CONCLUSIONS: Chemical modifications of ribonucleotides affect mRNA stability and translation efficiency. They thus constitute a newly discovered layer of gene expression regulation and have a profound effect on the development and functioning of various organisms, including plants.


Assuntos
Regulação da Expressão Gênica de Plantas/genética , Fenômenos Fisiológicos Vegetais/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
3.
Am J Bot ; 106(6): 894-900, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31162645

RESUMO

PREMISE: Polyploidy is known to cause physiological changes in plants which, in turn, can affect species interactions. One major physiological change predicted in polyploid plants is a heightened demand for growth-limiting nutrients. Consequently, we expect polyploidy to cause an increased reliance on the belowground mutualists that supply these growth-limiting nutrients. An important first step in investigating how polyploidy affects nutritional mutualisms in plants, then, is to characterize differences in the rate at which diploids and polyploids interact with belowground mutualists. METHODS: We used Heuchera cylindrica (Saxifragaceae) to test how polyploidy influences interactions with arbuscular mycorrhizal fungi (AMF). Here we first confirmed the presence of AMF in H. cylindrica, and then we used field-collected specimens to quantify and compare the presence of AMF structures while controlling for site-specific variation. RESULTS: Tetraploids had higher colonization rates as measured by total, hyphal, and nutritional-exchange structures; however, we found that diploids and tetraploids did not differ in vesicle colonization rates. CONCLUSIONS: The results suggest that polyploidy may alter belowground nutritional mutualisms with plants. Because colonization by nutritional-exchange structures was higher in polyploids but vesicle colonization was not, polyploids might form stronger associations with their AMF partners. Controlled experiments are necessary to test whether this pattern is driven by the direct effect of polyploidy on AMF colonization.


Assuntos
Heuchera/genética , Micorrizas/fisiologia , Poliploidia , Simbiose , Heuchera/microbiologia , Heuchera/fisiologia , Fenômenos Fisiológicos Vegetais/genética , Simbiose/genética
4.
Mol Ecol ; 28(10): 2559-2572, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30964953

RESUMO

Adaptation to changing environmental conditions represents a challenge to parthenogenetic organisms, and until now, how phenotypic variants are generated in clones in response to the selection pressure of their environment remains poorly known. The obligatory parthenogenetic root-knot nematode species Meloidogyne incognita has a worldwide distribution and is the most devastating plant-parasitic nematode. Despite its asexual reproduction, this species exhibits an unexpected capacity of adaptation to environmental constraints, for example, resistant hosts. Here, we used a genomewide comparative hybridization strategy to evaluate variations in gene copy numbers between genotypes of M. incognita resulting from two parallel experimental evolution assays on a susceptible vs. resistant host plant. We detected gene copy number variations (CNVs) associated with the ability of the nematodes to overcome resistance of the host plant, and this genetic variation may reflect an adaptive response to host resistance in this parthenogenetic species. The CNV distribution throughout the nematode genome is not random and suggests the occurrence of genomic regions more prone to undergo duplications and losses in response to the selection pressure of the host resistance. Furthermore, our analysis revealed an outstanding level of gene loss events in nematode genotypes that have overcome the resistance. Overall, our results support the view that gene loss could be a common class of adaptive genetic mechanism in response to a challenging new biotic environment in clonal animals.


Assuntos
Variações do Número de Cópias de DNA/genética , Evolução Molecular , Plantas/genética , Reprodução Assexuada/genética , Tylenchoidea/genética , Animais , Evolução Biológica , Genômica , Doenças das Plantas , Fenômenos Fisiológicos Vegetais/genética , Raízes de Plantas/genética , Plantas/parasitologia , Tylenchoidea/patogenicidade , Tylenchoidea/fisiologia
5.
Plant Sci ; 282: 49-59, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31003611

RESUMO

Plants are autotrophic organisms in which there are linear relationships between the rate at which organic biomass is accumulated and many ambient parameters such as water, nutrients, CO2 and solar radiation. These linear relationships are the result of good feedback regulation between a plants sensing of the environment and the optimization of its performance response. In this review, we suggest that continuous monitoring of the plant physiological profile in response to changing ambient conditions could be a useful new phenotyping tool, allowing the characterization and comparison of different levels of functional phenotypes and productivity. This functional physiological phenotyping (FPP) approach can be integrated into breeding programs, which are facing difficulties in selecting plants that perform well under abiotic stress. Moreover, high-throughput FPP will increase the efficiency of the selection of traits that are closely related to environmental interactions (such as plant water status, water-use efficiency, stomatal conductance, etc.) thanks to its high resolution and dynamic measurements. One of the important advantages of FPP is, its simplicity and effectiveness and compatibility with experimental methods that use load-cell lysimeters and ambient sensors. In the future, this platform could help with phenotyping of complex physiological traits, beneficial for yield gain to enhance functional breeding approaches and guide in crop modeling.


Assuntos
Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Melhoramento Vegetal , Fenótipo , Fenômenos Fisiológicos Vegetais/genética , Estresse Fisiológico
6.
Biol Res ; 52(1): 14, 2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30894225

RESUMO

BACKGROUND: Drought is a major abiotic stress affecting global wheat (Triticum aestivum L.) production. Exploration of drought-tolerant genes is essential for the genetic improvement of drought tolerance in wheat. Previous studies have shown that some histone encoding genes are involved in plant drought tolerance. However, whether the H2B family genes are involved in drought stress response remains unclear. METHODS: Here, we identified a wheat histone H2B family gene, TaH2B-7D, which was significantly up-regulated under drought stress conditions. Virus-induced gene silencing (VIGS) technology was used to further verify the function of TaH2B-7D in wheat drought tolerance. The phenotypic and physiological changes were examined in the TaH2B-7D knock-down plants. RESULTS: In the TaH2B-7D knock-down plants, relative electrolyte leakage rate and malonaldehyde (MDA) content significantly increased, while relative water content (RWC) and proline content significantly decreased compared with those in the non-knocked-down plants under drought stress conditions. TaH2B-7D knock-down plants exhibited severe sagging, wilting and dwarf phenotypes under drought stress conditions, but not in the non-knocked-down plants, suggesting that the former were more sensitive to drought stress. CONCLUSION: These results indicate that TaH2B-7D potentially plays a vital role in conferring drought tolerance in wheat.


Assuntos
Secas , Regulação da Expressão Gênica de Plantas/genética , Inativação Gênica , Proteínas de Plantas/genética , Estresse Fisiológico/genética , Triticum/genética , Fenótipo , Fenômenos Fisiológicos Vegetais/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Reação em Cadeia da Polimerase em Tempo Real , Estresse Fisiológico/fisiologia , Triticum/metabolismo
7.
Plant Cell Environ ; 42(3): 753-761, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30779228

RESUMO

Plants need to cope with changing environmental conditions, be it variable light or temperature, different availability of water or nutrients, or attack by pathogens or insects. Some of these changing conditions can become stressful and require strong countermeasures to ensure plant survival. Plants have evolved numerous distinct sensing and signalling mechanisms to perceive and respond appropriately to a variety of stresses. Because of the unpredictable nature of numerous stresses, resource-saving stress response mechanisms are inducible and become activated only upon a stress experience. Furthermore, plants have evolved mechanisms by which they can remember past stress events and prime their responses in order to react more rapidly or more strongly to recurrent stress. Research over the last decade has revealed mechanisms of this information storage and retrieval, which include epigenetic regulation, transcriptional priming, primed conformation of proteins, or specific hormonal or metabolic signatures. There is also increasing understanding of the ecological constraints and relevance of stress priming and memory. This special issue presents research articles and reviews addressing various aspects of this exciting and growing field of research. Here, we introduce the topic by referring to the articles published in this issue, and we outline open questions and future directions of research.


Assuntos
Adaptação Fisiológica/fisiologia , Epigênese Genética/fisiologia , Fenômenos Fisiológicos Vegetais , Transdução de Sinais/fisiologia , Estresse Fisiológico/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Fenômenos Fisiológicos Vegetais/genética , Transdução de Sinais/genética
8.
Plant Physiol ; 179(3): 1040-1049, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30602492

RESUMO

Desiccation tolerance was a critical adaptation for the colonization of land by early nonvascular plants. Resurrection plants have maintained or rewired these ancestral protective mechanisms, and desiccation-tolerant species are dispersed across the land plant phylogeny. Although common physiological, biochemical, and molecular signatures are observed across resurrection plant lineages, features underlying the recurrent evolution of desiccation tolerance are unknown. Here we used a comparative approach to identify patterns of genome evolution and gene duplication associated with desiccation tolerance. We identified a single gene family with dramatic expansion in all sequenced resurrection plant genomes and no expansion in desiccation-sensitive species. This gene family of early light-induced proteins (ELIPs) expanded in resurrection plants convergent through repeated tandem gene duplication. ELIPs are universally highly expressed during desiccation in all surveyed resurrection plants and may play a role in protecting against photooxidative damage of the photosynthetic apparatus during prolonged dehydration. Photosynthesis is particularly sensitive to dehydration, and the increased abundance of ELIPs may help facilitate the rapid recovery observed for most resurrection plants. Together, these observations support convergent evolution of desiccation tolerance in land plants through tandem gene duplication.


Assuntos
Genoma de Planta , Proteínas de Plantas/fisiologia , Plantas/genética , Estresse Fisiológico , Dessecação , Evolução Molecular , Duplicação Gênica , Filogenia , Fenômenos Fisiológicos Vegetais/genética , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas/metabolismo
9.
J Exp Bot ; 70(4): 1153-1165, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30590670

RESUMO

Leaves are beautifully specialized organs designed to maximize the use of light and CO2 for photosynthesis. Engineering leaf anatomy therefore holds great potential to enhance photosynthetic capacity. Here we review the effect of the dominant leaf anatomical traits on leaf photosynthesis and confirm that a high chloroplast surface area exposed to intercellular airspace per unit leaf area (Sc) is critical for efficient photosynthesis. The possibility of improving Sc through appropriately increasing mesophyll cell density is further analyzed. The potential influences of modifying mesophyll cell morphology on CO2 diffusion, light distribution within the leaf, and other physiological processes are also discussed. Some potential target genes regulating leaf mesophyll cell proliferation and expansion are explored. Indeed, more comprehensive research is needed to understand how manipulating mesophyll cell morphology through editing the potential target genes impacts leaf photosynthetic capacity and related physiological processes. This will pinpoint the targets for engineering leaf anatomy to maximize photosynthetic capacity.


Assuntos
Cloroplastos/fisiologia , Células do Mesofilo/metabolismo , Fotossíntese/fisiologia , Folhas de Planta/genética , Fenômenos Fisiológicos Vegetais/genética , Folhas de Planta/metabolismo
10.
Plant Cell Environ ; 42(3): 762-770, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29920687

RESUMO

For successful growth and development, plants constantly have to gauge their environment. Plants are capable to monitor their current environmental conditions, and they are also able to integrate environmental conditions over time and store the information induced by the cues. In a developmental context, such an environmental memory is used to align developmental transitions with favourable environmental conditions. One temperature-related example of this is the transition to flowering after experiencing winter conditions, that is, vernalization. In the context of adaptation to stress, such an environmental memory is used to improve stress adaptation even when the stress cues are intermittent. A somatic stress memory has now been described for various stresses, including extreme temperatures, drought, and pathogen infection. At the molecular level, such a memory of the environment is often mediated by epigenetic and chromatin modifications. Histone modifications in particular play an important role. In this review, we will discuss and compare different types of temperature memory and the histone modifications, as well as the reader, writer, and eraser proteins involved.


Assuntos
Adaptação Fisiológica , Cromatina/fisiologia , Fenômenos Fisiológicos Vegetais , Adaptação Fisiológica/genética , Adaptação Fisiológica/fisiologia , Epigênese Genética/genética , Epigênese Genética/fisiologia , Fenômenos Fisiológicos Vegetais/genética , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Temperatura
11.
J Exp Bot ; 70(3): 739-745, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30445526

RESUMO

The ability of an organism to change its phenotype in response to different environments, termed plasticity, is a particularly important characteristic to enable sessile plants to adapt to rapid changes in their surroundings. Plasticity is a quantitative trait that can provide a fitness advantage and mitigate negative effects due to environmental perturbations. Yet, its genetic basis is not fully understood. Alongside technological limitations, the main challenge in studying plasticity has been the selection of suitable approaches for quantification of phenotypic plasticity. Here, we propose a categorization of the existing quantitative measures of phenotypic plasticity into nominal and relative approaches. Moreover, we highlight the recent advances in the understanding of the genetic architecture underlying phenotypic plasticity in plants. We identify four pillars for future research to uncover the genetic basis of phenotypic plasticity, with emphasis on development of computational approaches and theories. These developments will allow us to perform specific experiments to validate the causal genes for plasticity and to discover their role in plant fitness and evolution.


Assuntos
Adaptação Fisiológica/genética , Fenômenos Fisiológicos Vegetais/genética , Adaptação Biológica , Evolução Biológica
12.
J Exp Bot ; 70(3): 757-770, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30452695

RESUMO

Virus-induced gene silencing (VIGS) is an RNA interference-based technology used to transiently knock down target gene expression by utilizing modified plant viral genomes. VIGS can be adapted to many angiosperm species that cover large phylogenetic distances, allowing the analysis of gene functions in species that are not amenable to stable genetic transformation. With a vast amount of sequence information already available and even more likely to become available in the future, VIGS provides a means to analyze the functions of candidate genes identified in large genomic or transcriptomic screens. Here, we provide a comprehensive overview of target species and VIGS vector systems, assess recent key publications in the field, and explain how plant viruses are modified to serve as VIGS vectors. As many reports on the VIGS technique are being published, we also propose minimal reporting guidelines for carrying out these experiments, with the aim of increasing comparability between experiments. Finally, we propose methods for the statistical evaluation of phenotypic results obtained with VIGS-treated plants, as analysis is challenging due to the predominantly transient nature of the silencing effect.


Assuntos
Botânica/métodos , Inativação Gênica , Genes de Plantas/fisiologia , Técnicas Genéticas , Fenômenos Fisiológicos Vegetais/genética , Vírus de Plantas/fisiologia , Regulação da Expressão Gênica de Plantas
13.
Trends Plant Sci ; 24(1): 49-57, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30409687

RESUMO

Root nodule endosymbiosis with nitrogen-fixing bacteria provides plants with unlimited access to fixed nitrogen, but at a significant energetic cost. Nodulation is generally considered to have originated in parallel in different lineages, but this hypothesis downplays the genetic complexity of nodulation and requires independent recruitment of many common features across lineages. Recent phylogenomic studies revealed that genes that function in establishing or maintaining nitrogen-fixing nodules are independently lost in non-nodulating relatives of nitrogen-fixing plants. In our opinion, these data are best explained by a scenario of a single gain followed by massively parallel loss of nitrogen-fixing root nodules triggered by events at geological scale.


Assuntos
Fixação de Nitrogênio , Nodulação , Evolução Biológica , Genes de Plantas/fisiologia , Fixação de Nitrogênio/genética , Filogenia , Fenômenos Fisiológicos Vegetais/genética , Nodulação/genética , Plantas/genética , Simbiose/genética
14.
Mol Ecol ; 28(2): 281-292, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30106192

RESUMO

Resource variation along abiotic gradients influences subsequent trophic interactions and these effects can be transmitted through entire food webs. Interactions along abiotic gradients can provide clues as to how organisms will face changing environmental conditions, such as future range shifts. However, it is challenging to find replicated systems to study these effects. Phytotelmata, such as those found in carnivorous plants, are isolated aquatic communities and thus form a good model for the study of replicated food webs. Due to the degraded nature of the prey, molecular techniques provide a useful tool to study these communities. We studied the pitcher plant Sarracenia purpurea L. in allochthonous populations along an elevational gradient in the Alps and Jura. We predicted that invertebrate richness in the contents of the pitcher plants would decrease with increasing elevation, reflecting harsher environmental conditions. Using metabarcoding of the COI gene, we sequenced the invertebrate contents of these pitcher plants. We assigned Molecular Operational Taxonomic Units at ordinal level as well as recovering species-level data. We found small but significant changes in community composition with elevation. These recovered sequences could belong to invertebrate prey, rotifer inquilines, pollinators and other animals possibly living inside the pitchers. However, we found no directional trend or site-based differences in MOTU richness with elevational gradient. Use of molecular techniques for dietary or contents analysis is a powerful way to examine numerous degraded samples, although factors such as DNA persistence and the relationship with species presence still have to be completely determined.


Assuntos
Carnívoros/genética , Código de Barras de DNA Taxonômico , Fenômenos Fisiológicos Vegetais/genética , Sarraceniaceae/fisiologia , Altitude , Animais , Biodiversidade , Carnívoros/fisiologia , DNA/genética , DNA/isolamento & purificação , Ecossistema , Cadeia Alimentar , Plantas/genética , Sarraceniaceae/genética
15.
Pest Manag Sci ; 75(1): 14-17, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30066358

RESUMO

Because of the role of the meristem in plant growth and reproduction, somatic mutations in plants have long been suspected of conferring herbivore and pathogen resistance on individual plants and, in the case of trees, individual branches within single plants. A few instances of resistance to phytophagous insects owing to somatic mutations have been reported in the literature. More recently, a striking example has demonstrated how somatic mutations confer resistance to an herbicide on an invasive plant, Hydrilla verticillata. The array of new methods for manipulating genomes (e.g., gene-editing) plus existing examples of somatic mutation-associated resistance suggest that such mutations might be useful in silviculture, agriculture, and horticulture. Answering several general questions about somatic mutations in plants would facilitate such applications: Why are so few examples reported? Do other cases exist but go undetected for want of adequate attention or methods? Under what circumstances do somatic mutations enter gametophytes? © 2018 Society of Chemical Industry.


Assuntos
Antibiose/genética , Resistência a Herbicidas/genética , Mutação , Fenômenos Fisiológicos Vegetais/genética , Plantas/genética , Animais , Insetos
16.
Plant J ; 97(1): 112-133, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30548574

RESUMO

In recent years developments in plant phenomic approaches and facilities have gradually caught up with genomic approaches. An opportunity lies ahead to dissect complex, quantitative traits when both genotype and phenotype can be assessed at a high level of detail. This is especially true for the study of natural variation in photosynthetic efficiency, for which forward genetics studies have yielded only a little progress in our understanding of the genetic layout of the trait. High-throughput phenotyping, primarily from chlorophyll fluorescence imaging, should help to dissect the genetics of photosynthesis at the different levels of both plant physiology and development. Specific emphasis should be directed towards understanding the acclimation of the photosynthetic machinery in fluctuating environments, which may be crucial for the identification of genetic variation for relevant traits in food crops. Facilities should preferably be designed to accommodate phenotyping of photosynthesis-related traits in such environments. The use of forward genetics to study the genetic architecture of photosynthesis is likely to lead to the discovery of novel traits and/or genes that may be targeted in breeding or bio-engineering approaches to improve crop photosynthetic efficiency. In the near future, big data approaches will play a pivotal role in data processing and streamlining the phenotype-to-gene identification pipeline.


Assuntos
Variação Genética , Genoma de Planta/genética , Genômica , Fenômica , Fotossíntese/genética , Plantas/genética , Aclimatação , Produtos Agrícolas , Genótipo , Fenótipo , Melhoramento Vegetal , Desenvolvimento Vegetal/genética , Fenômenos Fisiológicos Vegetais/genética
17.
Elife ; 72018 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-30484426

RESUMO

Biodiversity increases ecosystem functions underpinning a suite of services valued by society, including services provided by soils. To test whether, and how, future environments alter the relationship between biodiversity and multiple ecosystem functions, we measured grassland plant diversity effects on single soil functions and ecosystem multifunctionality, and compared relationships in four environments: ambient conditions, elevated atmospheric CO2, enriched N supply, and elevated CO2 and N in combination. Our results showed that plant diversity increased three out of four soil functions and, consequently, ecosystem multifunctionality. Remarkably, biodiversity-ecosystem function relationships were similarly significant under current and future environmental conditions, yet weaker with enriched N supply. Structural equation models revealed that plant diversity enhanced ecosystem multifunctionality by increasing plant community functional diversity, and the even provision of multiple functions. Conserving local plant diversity is therefore a robust strategy to maintain multiple valuable ecosystem services in both present and future environmental conditions.


Assuntos
Biodiversidade , Ecossistema , Fenômenos Fisiológicos Vegetais/genética , Solo , Atmosfera/química , Biomassa , Dióxido de Carbono/química , Meio Ambiente , Nitrogênio/química
18.
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
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