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1.
Tree Physiol ; 44(1)2024 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-38214910

RESUMO

Stem respiration (RS) substantially contributes to the return of photo assimilated carbon to the atmosphere and, thus, to the tree and ecosystem carbon balance. Stem CO2 efflux (ECO2) is often used as a proxy for RS. However, this metric has often been challenged because of the uncertain origin of CO2 emitted from the stem due to post-respiratory processes. In this Insight, we (i) describe processes affecting the quantification of RS, (ii) review common methodological approaches to quantify and model RS and (iii) develop a research agenda to fill the most relevant knowledge gaps that we identified. Dissolution, transport and accumulation of respired CO2 away from its production site, reassimilation of respired CO2 via stem photosynthesis and the enzyme phosphoenolpyruvate carboxylase, axial CO2 diffusion in the gas phase, shifts in the respiratory substrate and non-respiratory oxygen (O2) consumption are the most relevant processes causing divergence between RS and measured stem gas exchange (ECO2 or O2 influx, IO2). Two common methodological approaches to estimate RS, namely the CO2 mass balance approach and the O2 consumption technique, circumvent some of these processes but have yielded inconsistent results regarding the fate of respired CO2. Stem respiration modelling has recently progressed at the organ and tree levels. However, its implementation in large-scale models, commonly operated from a source-driven perspective, is unlikely to reflect adequate mechanisms. Finally, we propose hypotheses and approaches to advance the knowledge of the stem carbon balance, the role of sap pH on RS, the reassimilation of respired CO2, RS upscaling procedures, large-scale RS modelling and shifts in respiratory metabolism during environmental stress.


Assuntos
Dióxido de Carbono , Árvores , Árvores/metabolismo , Dióxido de Carbono/metabolismo , Ecossistema , Transporte Biológico , Carbono/metabolismo , Caules de Planta/metabolismo
2.
Proc Natl Acad Sci U S A ; 120(42): e2302069120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37824524

RESUMO

Stem cells are essential for the development and organ regeneration of multicellular organisms, so their infection by pathogenic viruses must be prevented. Accordingly, mammalian stem cells are highly resistant to viral infection due to dedicated antiviral pathways including RNA interference (RNAi). In plants, a small group of stem cells harbored within the shoot apical meristem generate all postembryonic above-ground tissues, including the germline cells. Many viruses do not proliferate in these cells, yet the molecular bases of this exclusion remain only partially understood. Here, we show that a plant-encoded RNA-dependent RNA polymerase, after activation by the plant hormone salicylic acid, amplifies antiviral RNAi in infected tissues. This provides stem cells with RNA-based virus sequence information, which prevents virus proliferation. Furthermore, we find RNAi to be necessary for stem cell exclusion of several unrelated RNA viruses, despite their ability to efficiently suppress RNAi in the rest of the plant. This work elucidates a molecular pathway of great biological and economic relevance and lays the foundations for our future understanding of the unique systems underlying stem cell immunity.


Assuntos
Vírus de RNA , Ácido Salicílico , Animais , Interferência de RNA , Vírus de RNA/genética , Células-Tronco/metabolismo , Caules de Planta/genética , Caules de Planta/metabolismo , RNA Interferente Pequeno/genética , RNA Viral/genética , Mamíferos/genética
3.
Plant Physiol ; 192(4): 3069-3087, 2023 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-37086475

RESUMO

WUSCHEL (WUS) and WUSCHEL-RELATED HOMEOBOX (WOX) proteins determine stem cell maintenance for continual plant growth and development under changing environmental conditions. Nutrient availability is an environmental factor that substantially controls plant growth and development. However, how plant stem cell homeostasis is regulated under nutrient deficiency remains to be elucidated. Here, we showed that cytosolic isocitrate dehydrogenase (ICDH) plays an important role in nutrient sensing of stem cells in Arabidopsis (Arabidopsis thaliana). Nutrient deficiency induced the cytoplasmic-to-nuclear translocation of cytosolic ICDH protein. ICDH can interact with WUS/WOX protein as a complex that further promotes WUS/WOX expression by binding to its promoter. WUS/WOX expression in the icdh-2 mutant was lower than that of wild-type plants under nutrient deficiency. Consistently, loss of ICDH function caused a more serious growth repression under nutrient deficiency that was independent of ICDH's catalytic activity. Therefore, cytosolic ICDH regulates stem cell homeostasis of plants in response to nutrient deficiency.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Homeodomínio/genética , Arabidopsis/metabolismo , Meristema/metabolismo , Caules de Planta/metabolismo , Nutrientes , Regulação da Expressão Gênica de Plantas
4.
Tree Physiol ; 43(2): 248-261, 2023 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-36209429

RESUMO

Stored water in inner tissues influences the plant water economy, which might be particularly relevant for trees facing increasing dry conditions due to climate change. We studied the water storage in the inner bark and the sapwood of Araucaria araucana (Molina) K. Koch. This species has an extremely thick inner bark and thus it can be used as a model system to assess the impact of internal water storage on plant water balance. Specifically, we analyzed the water circulation pathways in and out of the elastic water storages by using simultaneously frequency domain moisture sensors and dendrometers inserted in the inner bark and in the sapwood, and sap flow determinations during the dry season. The daily patterns of water content and expansion and contraction of the stem tissues were similar to the sap flow pattern. The whole-stem water content and diameter increased in the morning and decreased in the afternoon, contrary to the typical pattern observed in most tree species. An osmotic gradient favoring the water influx from sapwood to inner bark was observed in the morning. There were no lags in the onset of sap flow between different stem heights at the time that recharge of reservoirs occurred. Sap flow at 6 m height was higher than basal sap flow in the afternoon, when the sapwood water content started to decline followed by the water content of the inner bark. Inner bark and sapwood contributed 5-11% to total daily transpiration, allowing the maintenance of high water potentials in the dry season. Our results suggest that the stored water in the stems, the atypical dynamic of recharge and discharge of water from reservoirs and the high tissue capacitance may make an important contribution to the survival of A. araucana during drought periods by maintaining the water balance.


Assuntos
Araucaria araucana , Água , Água/metabolismo , Secas , Casca de Planta/metabolismo , Transpiração Vegetal , Ritmo Circadiano , Árvores/metabolismo , Caules de Planta/metabolismo
5.
Plant Physiol ; 190(3): 1731-1746, 2022 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-35951755

RESUMO

In plant stems, secondary vascular development is established through the differentiation of cylindrical vascular cambium, producing secondary xylem (wood) and phloem (bast), which have economic importance. However, there is a dearth of knowledge on the genetic mechanism underlying this process. NAC with Transmembrane Motif 1-like transcription factor 9 (NTL9) plays a central role in abiotic and immune signaling responses. Here, we investigated the role of NTL9 in vascular cambium development in Arabidopsis (Arabidopsis thaliana) inflorescence stems by identifying and characterizing an Arabidopsis phloem circular-timing (pct) mutant. The pct mutant exhibited enhanced vascular cambium formation following secondary phloem production. In the pct mutant, although normal organization in vascular bundles was maintained, vascular cambium differentiation occurred at an early stage of stem development, which was associated with increased expression of cambium-/phloem-related genes and enhanced cambium activity. The pct mutant stem phenotype was caused by a recessive frameshift mutation that disrupts the transmembrane (TM) domain of NTL9. Our results indicate that NTL9 functions as a negative regulator of cambial activity and has a suppressive role in developmental transition to the secondary growth phase in stem vasculature, which is necessary for its precise TM domain-mediated regulation.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Câmbio/metabolismo , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Xilema/genética , Xilema/metabolismo , Caules de Planta/genética , Caules de Planta/metabolismo , Regulação da Expressão Gênica de Plantas
6.
Nature ; 608(7923): 552-557, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35948636

RESUMO

As the climate changes, warmer spring temperatures are causing earlier leaf-out1-3 and commencement of CO2 uptake1,3 in temperate deciduous forests, resulting in a tendency towards increased growing season length3 and annual CO2 uptake1,3-7. However, less is known about how spring temperatures affect tree stem growth8,9, which sequesters carbon in wood that has a long residence time in the ecosystem10,11. Here we show that warmer spring temperatures shifted stem diameter growth of deciduous trees earlier but had no consistent effect on peak growing season length, maximum growth rates, or annual growth, using dendrometer band measurements from 440 trees across two forests. The latter finding was confirmed on the centennial scale by 207 tree-ring chronologies from 108 forests across eastern North America, where annual ring width was far more sensitive to temperatures during the peak growing season than in the spring. These findings imply that any extra CO2 uptake in years with warmer spring temperatures4,5 does not significantly contribute to increased sequestration in long-lived woody stem biomass. Rather, contradicting projections from global carbon cycle models1,12, our empirical results imply that warming spring temperatures are unlikely to increase woody productivity enough to strengthen the long-term CO2 sink of temperate deciduous forests.


Assuntos
Aquecimento Global , Estações do Ano , Temperatura , Árvores , Aclimatação , Biomassa , Dióxido de Carbono/metabolismo , Sequestro de Carbono , Modelos Climáticos , Florestas , Aquecimento Global/estatística & dados numéricos , América do Norte , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/metabolismo , Fatores de Tempo , Árvores/anatomia & histologia , Árvores/classificação , Árvores/crescimento & desenvolvimento , Árvores/metabolismo , Madeira/crescimento & desenvolvimento , Madeira/metabolismo
7.
Nat Plants ; 8(4): 346-355, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35347264

RESUMO

Gene duplications are a hallmark of plant genome evolution and a foundation for genetic interactions that shape phenotypic diversity1-5. Compensation is a major form of paralogue interaction6-8 but how compensation relationships change as allelic variation accumulates is unknown. Here we leveraged genomics and genome editing across the Solanaceae family to capture the evolution of compensating paralogues. Mutations in the stem cell regulator CLV3 cause floral organs to overproliferate in many plants9-11. In tomato, this phenotype is partially suppressed by transcriptional upregulation of a closely related paralogue12. Tobacco lost this paralogue, resulting in no compensation and extreme clv3 phenotypes. Strikingly, the paralogues of petunia and groundcherry nearly completely suppress clv3, indicating a potent ancestral state of compensation. Cross-species transgenic complementation analyses show that this potent compensation partially degenerated in tomato due to a single amino acid change in the paralogue and cis-regulatory variation that limits its transcriptional upregulation. Our findings show how genetic interactions are remodelled following duplications and suggest that dynamic paralogue evolution is widespread over short time scales and impacts phenotypic variation from natural and engineered mutations.


Assuntos
Sinais Direcionadores de Proteínas , Solanum lycopersicum , Regulação da Expressão Gênica de Plantas , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Meristema/metabolismo , Peptídeos/metabolismo , Caules de Planta/genética , Caules de Planta/metabolismo
8.
J Agric Food Chem ; 70(10): 3136-3141, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35232018

RESUMO

Maize stalks support leaves and reproductive structures and functionally support water and nutrient transport; besides, their anatomical and biochemical characteristics have been described as a plant defense against stress, also impacting economically important applications. In this study, we evaluated agronomical and stem description traits in a subset of maize inbred lines that showed variability for cell wall composition in the internodes. Overall, a great proportion of lignin subunit G and a low concentration of p-coumaric acid and lignin subunit S are beneficial for greater rind puncture resistance and taller plants, with a greater biomass yield. Also, the greater the proportions of subunit H, the longer the internode. Finally, the lower the total hemicellulose content, the greater the rind puncture resistance. Our results confirmed the effect of the cell wall on agronomic and stalk traits, which would be useful in applied breeding programs focused on biomass yield improvement.


Assuntos
Parede Celular , Melhoramento Vegetal , Biomassa , Parede Celular/química , Lignina/metabolismo , Caules de Planta/metabolismo , Zea mays/química
10.
Gene ; 823: 146384, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35248661

RESUMO

UV-B radiation is a typical environmental stressor that can promote phytochemical accumulation in plants. Taxus species are highly appreciated due to the existence of bioactive taxoids (especially paclitaxel) and flavonoids. However, the effect of UV-B radiation on taxoid and flavonoid biosynthesis in Taxus cuspidata Sieb. et Zucc. is largely unknown. In the present work, the accumulation of taxoids and flavonoids in T. cuspidata plantlets was significantly induced by 12 and 24 h of UV-B radiation (3 W/m2), and a large number of significantly differentially expressed genes were obtained via transcriptomic analysis. The significant up-regulation of antioxidant enzyme- and flavonoid biosynthesis-related genes (phenylalanine ammonia lyase 1, chalcone synthase 2, flavonol synthase 1, and flavonoid 3', 5'-hydroxylase 2), suggested that UV-B might cause the oxidative stress thus promoting flavonoid accumulation in T. cuspidata. Moreover, the expression of some genes related to jasmonate metabolism and taxoid biosynthesis (taxadiene synthase, baccatin III-3-amino 3-phenylpropanoyltransferase 1, taxadiene-5α-hydroxylase, and ethylene response factors 15) was significantly activated, which indicated that UV-B might initiate jasmonate signaling pathway that contributed to taxoid enhancement in T. cuspidata. Additionally, the identification of some up-regulated genes involved in lignin biosynthesis pathway indicated that the lignification process in T. cuspidata might be stimulated for defense against UV-B radiation. Overall, our findings provided a better understanding of some potential key genes associated with flavonoid and taxoid biosynthesis in T. cuspidata exposed to UV-B radiation.


Assuntos
Vias Biossintéticas , Flavonoides/biossíntese , Perfilação da Expressão Gênica/métodos , Caules de Planta/crescimento & desenvolvimento , Taxoides/metabolismo , Taxus/genética , Cromatografia Líquida de Alta Pressão , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Estresse Oxidativo , Proteínas de Plantas/genética , Caules de Planta/metabolismo , Caules de Planta/efeitos da radiação , RNA-Seq , Espectrometria de Massas em Tandem , Taxus/crescimento & desenvolvimento , Taxus/metabolismo , Taxus/efeitos da radiação , Raios Ultravioleta/efeitos adversos
11.
Proc Natl Acad Sci U S A ; 119(1)2022 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-34983847

RESUMO

Symplasmicly connected cells called sieve elements form a network of tubes in the phloem of vascular plants. Sieve elements have essential functions as they provide routes for photoassimilate distribution, the exchange of developmental signals, and the coordination of defense responses. Nonetheless, they are the least understood main type of plant cells. They are extremely sensitive, possess a reduced endomembrane system without Golgi apparatus, and lack nuclei and translation machineries, so that transcriptomics and similar techniques cannot be applied. Moreover, the analysis of phloem exudates as a proxy for sieve element composition is marred by methodological problems. We developed a simple protocol for the isolation of sieve elements from leaves and stems of Nicotiana tabacum at sufficient amounts for large-scale proteome analysis. By quantifying the enrichment of individual proteins in purified sieve element relative to bulk phloem preparations, proteins of increased likelyhood to function specifically in sieve elements were identified. To evaluate the validity of this approach, yellow fluorescent protein constructs of genes encoding three of the candidate proteins were expressed in plants. Tagged proteins occurred exclusively in sieve elements. Two of them, a putative cytochrome b561/ferric reductase and a reticulon-like protein, appeared restricted to segments of the endoplasmic reticulum (ER) that were inaccessible to green fluorescent protein dissolved in the ER lumen, suggesting a previously unknown differentiation of the endomembrane system in sieve elements. Evidently, our list of promising candidate proteins ( SI Appendix, Table S1) provides a valuable exploratory tool for sieve element biology.


Assuntos
Retículo Endoplasmático/metabolismo , Células Vegetais/metabolismo , Folhas de Planta/metabolismo , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Proteômica , Retículo Endoplasmático/genética , Folhas de Planta/citologia , Folhas de Planta/genética , Caules de Planta/citologia , Caules de Planta/genética , Plantas Geneticamente Modificadas/citologia , Plantas Geneticamente Modificadas/genética , /genética
12.
Microbiol Spectr ; 10(1): e0223021, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35019779

RESUMO

The Loess Plateau is located in the arid and semi-arid regions in northern China. The ecosystem is particularly sensitive to natural and anthropogenic disturbances. Fungi can produce extracellular enzymes, decompose a variety of organic matter, and regulate carbon and nutrient balance. We studied the changes of soil fungal community compositions in response to straw, inorganic fertilizer, and compost in a typical farmland in the Loess Plateau. Our results demonstrated that the addition of straw significantly reduces the Shannon index of the fungal community, in addition, the participation of straw significantly affects the composition of the fungal community. Functional prediction based on FUNGuild showed that straw significantly reduced the relative abundance of saprotrophs, pathotrophs, symbiotrophs, lichenized, ectomycorrhizal, and plant pathogens. Although fertilization practices destroyed the co-occurrence pattern among the fungal species, the addition of straw alleviated this affect. No significant effect of straw, compost, and inorganic fertilizers on the co-occurrence pattern among species in the soil fungal community was observed. Compared with compost and inorganic fertilizer, the addition of straw shaped the community composition by changing the relative abundance of fungal functional taxa. Thus, in the fragile Loess Plateau environment, over-fertilizing or non-order-fertilizing may destroy the co-occurrence pattern of the fungal communities and Loess Plateau ecosystem. IMPORTANCE Determining the response of soil fungi in sensitive ecosystems to external environmental disturbances is an important, yet little-known, topic in microbial ecology. In this study, we evaluated the impact of traditional fertilization management practices on the composition, co-occurrence pattern, and functional groups of fungal communities in loessial soil. Our results show that in the fragile Loess Plateau environment, fertilizer management changed the composition of the fungal community and disrupted the co-occurrence pattern between fungi. The application of straw alleviates the destroying of the co-occurrence pattern. The current research emphasizes the necessity of rational fertilization of farmland in loessial soil.


Assuntos
Fertilizantes/análise , Fungos/isolamento & purificação , Micobioma , China , Compostagem , Ecossistema , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Caules de Planta/metabolismo , Caules de Planta/microbiologia , Solo/química , Microbiologia do Solo
13.
BMC Plant Biol ; 22(1): 53, 2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35081916

RESUMO

BACKGROUND: Salinization of soil is an urgent problem that restricts agroforestry production and environmental protection. Substantial accumulation of metal ions or highly alkaline soil alters plant metabolites and may even cause plant death. To explore the differences in the response strategies between Suaeda salsa (S. salsa) and Puccinellia tenuiflora (P. tenuiflora), two main constructive species that survive in saline-alkali soil, their metabolic differences were characterized. RESULT: Metabolomics was conducted to study the role of metabolic differences between S. salsa and P. tenuiflora under saline-alkali stress. A total of 68 significantly different metabolites were identified by GC-MS, including 9 sugars, 13 amino acids, 8 alcohols, and 34 acids. A more detailed analysis indicated that P. tenuiflora utilizes sugars more effectively and may be saline-alkali tolerant via sugar consumption, while S. salsa utilizes mainly amino acids, alcohols, and acids to resist saline-alkali stress. Measurement of phenolic compounds showed that more C6C3C6-compounds accumulated in P. tenuiflora, while more C6C1-compounds, phenolic compounds that can be used as signalling molecules to defend against stress, accumulated in S. salsa. CONCLUSIONS: Our observations suggest that S. salsa resists the toxicity of saline-alkali stress using aboveground organs and that P. tenuiflora eliminates this toxicity via roots. S. salsa has a stronger habitat transformation ability and can provide better habitat for other plants.


Assuntos
Chenopodiaceae/metabolismo , Pradaria , Poaceae/metabolismo , Solo/química , Ácidos/metabolismo , Álcoois/metabolismo , Álcalis , China , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Caules de Planta/química , Caules de Planta/metabolismo , Salinidade , Tolerância ao Sal , Plantas Tolerantes a Sal/fisiologia , Especificidade da Espécie , Estresse Fisiológico
14.
Plant Sci ; 314: 111099, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34895537

RESUMO

Abiotic and biotic stresses are the major factors limiting plant growth. Arabidopsis E3 SUMO ligase SIZ1 plays an essential role in plant stress tolerance. Herein, we identified a SIZ/PAIS-type protein in pepper (Capsicum annuum), namely CaSIZ1, which shares 60 % sequence identity with AtSIZ1. The stems and flowers of pepper had a relatively higher expression of CaSIZ1 than the fruits, leaves, and roots. ABA and NaCl treatments induced CaSIZ1. CaSIZ1 protein was localized in the nucleus and partially rescued the dwarf and ABA-sensitive phenotypes of Atsiz1-2, suggesting the functional replacement of CaSIZ1 with AtSIZ1. We found that CaSIZ1 interacted with CaABI5, and ABA promoted the accumulation of SUMO conjugates in pepper. CaSIZ1 knockdown did not only reduce ABA-induced SUMOylation, but also attenuated the salt tolerance of pepper. Overall, the results of this study suggest that CaSIZ1 has a significant role in ABA-induced SUMOylation and stress response.


Assuntos
Ácido Abscísico/metabolismo , Capsicum/genética , Capsicum/metabolismo , Estresse Salino/efeitos dos fármacos , Tolerância ao Sal/genética , Sumoilação/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas/genética , Sumoilação/genética , /metabolismo , Verduras/genética , Verduras/metabolismo
15.
Plant Cell Environ ; 45(4): 1270-1285, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34914118

RESUMO

Stem respiration (RS ) plays a crucial role in plant carbon budgets. However, its poor understanding limits our ability to model woody tissue and whole-tree respiration. A biophysical model of stem water and carbon fluxes (TReSpire) was calibrated on cedar, maple and oak trees during spring and late summer. For this, stem sap flow, water potential, diameter variation, temperature, CO2 efflux, allometry and biochemistry were monitored. Shoot photosynthesis (PN ) and nonstructural carbohydrates (NSC) were additionally measured to evaluate source-sink relations. The highest RS and stem growth was found in maple and oak during spring, both being seasonally decoupled from PN and [NSC]. Temperature largely affected maintenance respiration (RM ) in the short term, but temperature-normalized RM was highly variable on a seasonal timescale. Overall, most of the respired CO2 radially diffused to the atmosphere (>87%) while the remainder was transported upward with the transpiration stream. The modelling exercise highlights the sink-driven behaviour of RS and the significance of overall metabolic activity on nitrogen (N) allocation patterns and N-normalized respiratory costs to capture RS variability over the long term. These insights should be considered when modelling plant respiration, whose representation is currently biased towards a better understanding of leaf metabolism.


Assuntos
Acer , Xilema , Carbono/metabolismo , Dióxido de Carbono/metabolismo , Caules de Planta/metabolismo , Respiração , Estações do Ano , Árvores/metabolismo , Água/metabolismo , Xilema/metabolismo
16.
Plant J ; 109(1): 64-76, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34695260

RESUMO

Maize (Zea mays L.) silk contains high levels of flavonoids and is widely used to promote human health. Isoorientin, a natural C-glycoside flavone abundant in maize silk, has attracted considerable attention due to its potential value. Although different classes of flavonoid have been well characterized in plants, the genes involved in the biosynthesis of isoorientin in maize are largely unknown. Here, we used targeted metabolic profiling of isoorientin on the silks in an association panel consisting of 294 maize inbred lines. We identified the gene ZmCGT1 by genome-wide association analysis. The ZmCGT1 protein was characterized as a 2-hydroxyflavanone C-glycosyltransferase that can C-glycosylate 2-hydroxyflavanone to form flavone-C-glycoside after dehydration. Moreover, ZmCGT1 overexpression increased isoorientin levels and RNA interference-mediated ZmCGT1 knockdown decreased accumulation of isoorientin in maize silk. Further, two nucleotide polymorphisms, A502C and A1022G, which led to amino acid changes I168L and E341G, respectively, were identified to be functional polymorphisms responsible for the natural variation in isoorientin levels. In summary, we identified the gene ZmCGT1, which plays an important role in isoorientin biosynthesis, providing insights into the genetic basis of the natural variation in isoorientin levels in maize silk. The identified favorable CG allele of ZmCGT1 may be further used for genetic improvement of nutritional quality in maize.


Assuntos
Variação Genética , Glicosiltransferases/metabolismo , Luteolina/biossíntese , Zea mays/genética , Flavonas/biossíntese , Flavonas/química , Estudo de Associação Genômica Ampla , Glicosiltransferases/genética , Luteolina/química , Metaboloma , Folhas de Planta/química , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/química , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Caules de Planta/química , Caules de Planta/genética , Caules de Planta/metabolismo , Zea mays/química , Zea mays/metabolismo
17.
Rapid Commun Mass Spectrom ; 36(5): e9232, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34862674

RESUMO

RATIONALE: New methods to measure stable isotopes of soil and tree water directly in the field enable us to increase the temporal resolution of obtained data and advance our knowledge on the dynamics of soil and plant water fluxes. Only few field applications exist. However, these are needed to further improve novel methods and hence exploit their full potential. METHODS: We tested the borehole equilibration method in the field and collected in situ and destructive samples of stable isotopes of soil, trunk and root xylem water over a 2.5-month experiment in a tropical dry forest under natural abundance conditions and following labelled irrigation. Water from destructive samples was extracted using cryogenic vacuum extraction. Isotope ratios were determined with IRIS instruments using cavity ring-down spectroscopy both in the field and in the laboratory. RESULTS: In general, timelines of both methods agreed well for both soil and xylem samples. Irrigation labelled with heavy hydrogen isotopes clearly impacted the isotope composition of soil water and one of the two studied tree species. Inter-method deviations increased in consequence of labelling, which revealed their different capabilities to cover spatial and temporal heterogeneities. CONCLUSIONS: We applied the novel borehole equilibration method in a remote field location. Our experiment reinforced the potential of this in situ method for measuring xylem water isotopes in both tree trunks and roots and confirmed the reliability of gas permeable soil probes. However, in situ xylem measurements should be further developed to reduce the uncertainty within the range of natural abundance and hence enable their full potential.


Assuntos
Deutério/análise , Caules de Planta/química , Solo/química , Árvores/química , Água/química , Xilema/química , Irrigação Agrícola , Transporte Biológico , Deutério/metabolismo , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Estações do Ano , Árvores/metabolismo , Água/metabolismo , Xilema/metabolismo
18.
Carbohydr Polym ; 276: 118781, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34823794

RESUMO

Plant cell walls provide essential functions in cell recognition, differentiation, adhesion and wound responses. Therefore, it is tempting to hypothesize that cell walls play a key role in grafting, but to date there are no quantitative studies targeting on cell wall changes during grafting. The aim of this work was to investigate the dynamics of pectic and hemicellulosic polysaccharides at the graft junctions in tomato homografts throughout the first 12 days after grafting. Cell wall fractionation, combined with ATR-FTIR spectroscopy and gas-chromatography, evidenced a marked increase in pectin content and a decrease in the degree of methyl-esterification of homogalacturonan in scion and rootstock throughout grafting. Also, recovery of tightly-bound hemicelluloses decreased at late times after grafting suggesting an increase of cross-linked hemicelluloses along grafting. In addition, immuno-dot assays revealed an increase in xyloglucan and arabinogalactan proteins in the first days after grafting, pointing to a presumed role in tissue adhesion-cohesion.


Assuntos
Parede Celular/metabolismo , Polissacarídeos/metabolismo , Solanum lycopersicum/metabolismo , Parede Celular/química , Cromatografia Gasosa/métodos , Glucanos/metabolismo , Solanum lycopersicum/química , Mucoproteínas/metabolismo , Pectinas/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Polissacarídeos/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Xilanos/metabolismo
19.
J Sci Food Agric ; 102(3): 1146-1154, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34329483

RESUMO

BACKGROUND: To date, fungus-assisted pretreatment of agricultural residue has not become the preferred method to produce protein-enriched and ruminally digestible animal feed because of low time efficiency of fungal delignification and protein production, i.e. the long solid-state fermentation period, and because of laccase as a potential inhibitor of cellulose activity. In this study, response surface methodology was employed to optimize the parameters in the process of producing nutritious animal feed from wheat straw with Inonotus obliquus pretreatment. RESULTS: The mineral salt solution containing (w/v) (NH4 )2 SO4 1%, MgSO4 ·7H2 O 0.03%, KH2 PO4 0.011%, Tween-80 0.4%, and corn starch 10% with pH of 7.4 was optimized. Inonotus obliquus rapidly and completely colonized on wheat straw with an ergosterol content of 280 µg g-1 dry matter, consuming 45% of lignin after 15 days of fermentation, producing maximums of lignin peroxidase (1729 IU g-1 ), manganese peroxidase (610 IU g-1 ) and laccase (98 IU g-1 ) on days 5, 15, and 25, respectively. The crude protein (102.4 g kg-1 ) of 15-day fermented wheat straw increased by ~132%. After hydrolysis, the essential protein-bound amino acids (15.3 g kg-1 ) increased by ~47%, within which Met and Lys measured ~1070% and ~60% higher. The treatment with I. obliquus also improved the in vitro gas production after 72 h (IVGP72 ) of wheat straw to 178.8 mL g-1 organic matter (~43% increase). CONCLUSION: For the first time, we found that I. obliquus is an effective white rot fungus turning wheat straw into ruminally digestible animal feed without laccase inhibitor.


Assuntos
Ração Animal/análise , Digestão/efeitos da radiação , Manipulação de Alimentos/métodos , Inonotus/metabolismo , Lignina/metabolismo , Metionina/análise , Proteínas de Plantas/metabolismo , Triticum/metabolismo , Fermentação , Hidrólise , Lignina/análise , Metionina/metabolismo , Proteínas de Plantas/análise , Caules de Planta/química , Caules de Planta/metabolismo , Triticum/química
20.
J Sci Food Agric ; 102(1): 19-40, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34453323

RESUMO

Eleocharis dulcis, an aquatic plant belonging to Cyperaceae family, is indigenous to Asia, and also occurs in tropical Africa and Australia. The edible corm part of E. dulcis is a commonly consumed aquatic vegetable with a planting area of 44.46 × 103 hm2 in China. This work aims to explore the potential of E. dulcis corm for use as a new food source for sufficient nutrients and health benefits by reviewing its nutrients, phytochemicals, functions, processing and food products. Eleocharis dulcis corm contains starches, dietary fibers, non-starch polysaccharides, proteins, amino acids, phenolics, sterols, puchiin, saponins, minerals and vitamins. Among them, phenolics including flavonoids and quinones could be the major bioconstituents that largely contribute to antioxidant, anti-inflammatory, antibacterial, antitumor, hepatoprotective, neuroprotective and hypolipidemic functions. Peel wastes of E. dulcis corm tend to be enriched in phenolics to a much higher extent than the edible pulp. Fresh-cut E. dulcis corm can be consumed as a ready-to-eat food or processed into juice for beverage production, and anti-browning processing is a key to prolonging shelf life. Present food products of E. dulcis corm are centered on various fruit and vegetable beverages, and suffer from single categories and inadequate development. In brief, underutilized E. dulcis corm possesses great potential for use as a new food source for sufficient nutrients and health benefits. © 2021 Society of Chemical Industry.


Assuntos
Eleocharis/química , Compostos Fitoquímicos/química , Animais , Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Anti-Inflamatórios/química , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacologia , Antioxidantes/química , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Eleocharis/metabolismo , Manipulação de Alimentos , Humanos , Compostos Fitoquímicos/metabolismo , Compostos Fitoquímicos/farmacologia , Caules de Planta/química , Caules de Planta/metabolismo
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