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2.
Nat Commun ; 13(1): 652, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115512

RESUMO

Stomatal opening requires the provision of energy in the form of ATP for proton pumping across the guard cell (GC) plasma membrane and for associated metabolic rearrangements. The source of ATP for GCs is a matter of ongoing debate that is mainly fuelled by controversies around the ability of GC chloroplasts (GCCs) to perform photosynthesis. By imaging compartment-specific fluorescent ATP and NADPH sensor proteins in Arabidopsis, we show that GC photosynthesis is limited and mitochondria are the main source of ATP. Unlike mature mesophyll cell (MC) chloroplasts, which are impermeable to cytosolic ATP, GCCs import cytosolic ATP through NUCLEOTIDE TRANSPORTER (NTT) proteins. GCs from ntt mutants exhibit impaired abilities for starch biosynthesis and stomatal opening. Our work shows that GCs obtain ATP and carbohydrates via different routes from MCs, likely to compensate for the lower chlorophyll contents and limited photosynthesis of GCCs.


Assuntos
Trifosfato de Adenosina/metabolismo , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Estômatos de Plantas/metabolismo , Amido/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Transporte Biológico , Cloroplastos/efeitos dos fármacos , Cloroplastos/efeitos da radiação , Citosol/metabolismo , Peróxido de Hidrogênio/farmacologia , Luz , Células do Mesofilo/citologia , Células do Mesofilo/metabolismo , Células do Mesofilo/efeitos da radiação , Microscopia Confocal , NADP/metabolismo , Proteínas de Transporte de Nucleotídeos/genética , Proteínas de Transporte de Nucleotídeos/metabolismo , Oxidantes/farmacologia , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Estômatos de Plantas/citologia , Estômatos de Plantas/fisiologia , Plantas Geneticamente Modificadas
3.
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 , Tabaco/metabolismo , 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 , Tabaco/citologia , Tabaco/genética
4.
Plant Cell Rep ; 41(2): 319-335, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34837515

RESUMO

KEY MESSAGE: Elevated expression of nucleotide-binding and leucine-rich repeat proteins led to closer vein spacing and higher vein density in rice leaves. To feed the growing global population and mitigate the negative effects of climate change, there is a need to improve the photosynthetic capacity and efficiency of major crops such as rice to enhance grain yield potential. Alterations in internal leaf morphology and cellular architecture are needed to underpin some of these improvements. One of the targets is to generate a "Kranz-like" anatomy in leaves that includes decreased interveinal spacing close to that in C4 plant species. As C4 photosynthesis has evolved from C3 photosynthesis independently in multiple lineages, the genes required to facilitate C4 may already be present in the rice genome. The Taiwan Rice Insertional Mutants (TRIM) population offers the advantage of gain-of-function phenotype trapping, which accelerates the identification of rice gene function. In the present study, we screened the TRIM population to determine the extent to which genetic plasticity can alter vein density (VD) in rice. Close vein spacing mutant 1 (CVS1), identified from a VD screening of approximately 17,000 TRIM lines, conferred heritable high leaf VD. Increased vein number in CVS1 was confirmed to be associated with activated expression of two nucleotide-binding and leucine-rich repeat (NB-LRR) proteins. Overexpression of the two NB-LRR genes individually in rice recapitulates the high VD phenotype, due mainly to reduced interveinal mesophyll cell (M cell) number, length, bulliform cell size and thus interveinal distance. Our studies demonstrate that the trait of high VD in rice can be achieved by elevated expression of NB-LRR proteins limited to no yield penalty.


Assuntos
/genética , Proteínas NLR/genética , Oryza/genética , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/genética , DNA Bacteriano , Resistência à Doença/genética , Expressão Ectópica do Gene , Regulação da Expressão Gênica de Plantas , Células do Mesofilo , Mutação , Proteínas NLR/metabolismo , Oryza/anatomia & histologia , Fotossíntese , Folhas de Planta/citologia , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Plântula/anatomia & histologia , Plântula/genética
5.
Int J Mol Sci ; 22(20)2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34681874

RESUMO

In recent decades, atmospheric pollution led to a progressive reduction of the ozone layer with a consequent increase in UV-B radiation. Despite the high adaptation of olive trees to the Mediterranean environment, the progressive increase of UV-B radiation is a risk factor for olive tree cultivation. It is therefore necessary to understand how high levels of UV-B radiation affect olive plants and to identify olive varieties which are better adapted. In this study we analyzed two Italian olive varieties subjected to chronic UV-B stress. We focused on the effects of UV-B radiation on RubisCO, in terms of quantity, enzymatic activity and isoform composition. In addition, we also analyzed changes in the activity of antioxidant enzymes (SOD, CAT, GPox) to get a comprehensive picture of the antioxidant system. We also evaluated the effects of UV-B on the enzyme sucrose synthase. The overall damage at biochemical level was also assessed by analyzing changes in Hsp70, a protein triggered under stress conditions. The results of this work indicate that the varieties (Giarraffa and Olivastra Seggianese) differ significantly in the use of specific antioxidant defense systems, as well as in the activity and isoform composition of RubisCO. Combined with a different use of sucrose synthase, the overall picture shows that Giarraffa optimized the use of GPox and opted for a targeted choice of RubisCO isoforms, in addition to managing the content of sucrose synthase, thereby saving energy during critical stress points.


Assuntos
Antioxidantes/metabolismo , Olea/metabolismo , Olea/efeitos da radiação , Proteínas de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Enzimas/metabolismo , Glucosiltransferases/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Itália , Peroxidação de Lipídeos/efeitos da radiação , Malondialdeído/metabolismo , Microscopia Eletrônica de Transmissão , Olea/citologia , Folhas de Planta/citologia , Folhas de Planta/efeitos da radiação , Raios Ultravioleta
6.
Plant J ; 108(6): 1597-1608, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34612535

RESUMO

Maize leaf angle (LA) is a complex quantitative trait that is controlled by developmental signals, hormones, and environmental factors. However, the connection between histone methylation and LAs in maize remains unclear. Here, we reported that SET domain protein 128 (SDG128) is involved in leaf inclination in maize. Knockdown of SDG128 using an RNA interference approach resulted in an expanded architecture, less large vascular bundles, more small vascular bundles, and larger spacing of large vascular bundles in the auricles. SDG128 interacts with ZmGID2 both in vitro and in vivo. Knockdown of ZmGID2 also showed a larger LA with less large vascular bundles and larger spacing of vascular bundles. In addition, the transcription level of cell wall expansion family genes ZmEXPA1, ZmEXPB2, and GRMZM2G005887; transcriptional factor genes Lg1, ZmTAC1, and ZmCLA4; and auxin pathway genes ZmYUCCA7, ZmYUCCA8, and ZmARF22 was reduced in SDG128 and ZmGID2 knockdown plants. SDG128 directly targets ZmEXPA1, ZmEXPB2, LG1, and ZmTAC1 and is required for H3K4me3 deposition at these genes. Together, the results of the present study suggest that SDG128 and ZmGID2 are involved in the maize leaf inclination.


Assuntos
Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Zea mays/fisiologia , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Regulação da Expressão Gênica de Plantas , Histonas , Ácidos Indolacéticos/metabolismo , Mutação , Folhas de Planta/citologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Interferência de RNA , Zea mays/citologia
7.
Plant J ; 108(6): 1690-1703, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34628678

RESUMO

The riboflavin derivatives flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are essential cofactors for enzymes in multiple cellular processes. Characterizing mutants with impaired riboflavin metabolism can help clarify the role of riboflavin in plant development. Here, we characterized a rice (Oryza sativa) white and lesion-mimic (wll1) mutant, which displays a lesion-mimic phenotype with white leaves, chlorophyll loss, chloroplast defects, excess reactive oxygen species (ROS) accumulation, decreased photosystem protein levels, changes in expression of chloroplast development and photosynthesis genes, and cell death. Map-based cloning and complementation test revealed that WLL1 encodes lumazine synthase, which participates in riboflavin biosynthesis. Indeed, the wll1 mutant showed riboflavin deficiency, and application of FAD rescued the wll1 phenotype. In addition, transcriptome analysis showed that cytokinin metabolism was significantly affected in wll1 mutant, which had increased cytokinin and δ-aminolevulinic acid contents. Furthermore, WLL1 and riboflavin synthase (RS) formed a complex, and the rs mutant had a similar phenotype to the wll1 mutant. Taken together, our findings revealed that WLL1 and RS play pivotal roles in riboflavin biosynthesis, which is necessary for ROS balance and chloroplast development in rice.


Assuntos
Cloroplastos/fisiologia , Complexos Multienzimáticos/metabolismo , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Clorofila/genética , Clorofila/metabolismo , Citocininas/genética , Citocininas/metabolismo , Dano ao DNA , Evolução Molecular , Flavina-Adenina Dinucleotídeo/genética , Flavina-Adenina Dinucleotídeo/metabolismo , Regulação da Expressão Gênica de Plantas , Complexos Multienzimáticos/genética , Mutação , Fenótipo , Filogenia , Folhas de Planta/citologia , Folhas de Planta/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Riboflavina/genética , Riboflavina/metabolismo , Técnicas do Sistema de Duplo-Híbrido
8.
Int J Mol Sci ; 22(20)2021 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-34681824

RESUMO

Chloroplasts play an essential role in plant growth and development. Any factors affecting chloroplast development will lead to abnormal plant growth. Here, we characterized a new maize mutant, albino seedling mutant 81647 (as-81647), which exhibits an entirely albino phenotype in leaves and eventually died before the three-leaf stage. Transmission electron microscopy (TEM) demonstrated that the chloroplast thylakoid membrane was impaired and the granum lamellae significantly decreased in as-81647. Map-based cloning and transgenic analysis confirmed that PPR647 encodes a new chloroplast protein consisting of 11 pentratricopeptide repeat domains. Quantitative real-time PCR (qRT-PCR) assays and transcriptome analysis (RNA-seq) showed that the PPR647 mutation significantly disrupted the expression of PEP-dependent plastid genes. In addition, RNA splicing and RNA editing of multiple chloroplast genes showed severe defects in as-81647. These results indicated that PPR647 is crucial for RNA editing, RNA splicing of chloroplast genes, and plays an essential role in chloroplast development.


Assuntos
Cloroplastos/fisiologia , Proteínas de Plantas/genética , Edição de RNA , Splicing de RNA , RNA de Cloroplastos/metabolismo , Zea mays/genética , Zea mays/metabolismo , Cloroplastos/ultraestrutura , Regulação da Expressão Gênica de Plantas , Genes de Cloroplastos , Mutação , Fenótipo , Filogenia , Folhas de Planta/citologia , Proteínas de Plantas/metabolismo , Domínios Proteicos , Plântula/genética , Plântula/metabolismo , Tilacoides/fisiologia , Tilacoides/ultraestrutura
9.
Plant J ; 108(2): 541-554, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34403543

RESUMO

The enucleated vascular elements of the xylem and the phloem offer an excellent system to test the effect of ploidy on plant function because variation in vascular geometry has a direct influence on transport efficiency. However, evaluations of conduit sizes in polyploid plants have remained elusive, most remarkably in woody species. We used a combination of molecular, physiological and microscopy techniques to model the hydraulic resistance between source and sinks in tetraploid and diploid mango trees. Tetraploids exhibited larger chloroplasts, mesophyll cells and stomatal guard cells, resulting in higher leaf elastic modulus and lower dehydration rates, despite the high water potentials of both ploidies in the field. Both the xylem and the phloem displayed a scaling of conduits with ploidy, revealing attenuated hydraulic resistance in tetraploids. Conspicuous wall hygroscopic moieties in the cells involved in transpiration and transport indicate a role in volumetric adjustments as a result of turgor change in both ploidies. In autotetraploids, the enlargement of organelles, cells and tissues, which are critical for water and photoassimilate transport at long distances, point to major physiological novelties associated with whole-genome duplication.


Assuntos
Mangifera/fisiologia , Floema/fisiologia , Folhas de Planta/química , Ploidias , Xilema/fisiologia , Parede Celular/química , Inflorescência/fisiologia , Mangifera/citologia , Mangifera/genética , Células Vegetais/química , Folhas de Planta/anatomia & histologia , Folhas de Planta/citologia , Folhas de Planta/genética , Caules de Planta/fisiologia , Estômatos de Plantas/química , Árvores/citologia , Árvores/genética , Árvores/fisiologia
10.
Nat Commun ; 12(1): 4327, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267202

RESUMO

Trivalent rare earth elements (REEs) are widely used in agriculture. Aerially applied REEs enter leaf epidermal cells by endocytosis and act systemically to improve the growth of the whole plant. The mechanistic basis of their systemic activity is unclear. Here, we show that treatment of Arabidopsis leaves with trivalent lanthanum [La(III)], a representative of REEs, triggers systemic endocytosis from leaves to roots. La(III)-induced systemic endocytosis requires AtrbohD-mediated reactive oxygen species production and jasmonic acid. Systemic endocytosis impacts the accumulation of mineral elements and the development of roots consistent with the growth promoting effects induced by aerially applied REEs. These findings provide insights into the mechanistic basis of REE activity in plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Lantânio/farmacologia , NADPH Oxidases/metabolismo , Arabidopsis/citologia , Proteínas de Arabidopsis/genética , Ciclopentanos/metabolismo , Endocitose/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde/genética , Minerais/metabolismo , NADPH Oxidases/genética , Oxilipinas/metabolismo , Células Vegetais/efeitos dos fármacos , Folhas de Planta/citologia , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Transdução de Sinais
11.
Nat Plants ; 7(6): 826-841, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34112988

RESUMO

The leaf epidermis is a dynamic biomechanical shell that integrates growth across spatial scales to influence organ morphology. Pavement cells, the fundamental unit of this tissue, morph irreversibly into highly lobed cells that drive planar leaf expansion. Here, we define how tissue-scale cell wall tensile forces and the microtubule-cellulose synthase systems dictate the patterns of interdigitated growth in real time. A morphologically potent subset of cortical microtubules span the periclinal and anticlinal cell faces to pattern cellulose fibres that generate a patch of anisotropic wall. The subsequent local polarized growth is mechanically coupled to the adjacent cell via a pectin-rich middle lamella, and this drives lobe formation. Finite element pavement cell models revealed cell wall tensile stress as an upstream patterning element that links cell- and tissue-scale biomechanical parameters to interdigitated growth. Cell lobing in leaves is evolutionarily conserved, occurs in multiple cell types and is associated with important agronomic traits. Our general mechanistic models of lobe formation provide a foundation to analyse the cellular basis of leaf morphology and function.


Assuntos
Arabidopsis/citologia , Células Vegetais , Folhas de Planta/citologia , Folhas de Planta/crescimento & desenvolvimento , Arabidopsis/crescimento & desenvolvimento , Fenômenos Biomecânicos , Forma Celular , Parede Celular/fisiologia , Celulose/metabolismo , Análise de Elementos Finitos , Microscopia Eletrônica de Transmissão , Microtúbulos/metabolismo , Modelos Biológicos , Mutação , Células Vegetais/metabolismo , Plantas Geneticamente Modificadas , Plasmodesmos
12.
Int J Mol Sci ; 22(9)2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-34064353

RESUMO

The lipid bilayer matrix of the thylakoid membrane of cyanobacteria and chloroplasts of plants and algae is mainly composed of uncharged galactolipids, but also contains anionic lipids sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) as major constituents. The necessity of PG for photosynthesis is evident in all photosynthetic organisms examined to date, whereas the requirement of SQDG varies with species. In plants, although PG and SQDG are also found in non-photosynthetic plastids, their importance for the growth and functions of non-photosynthetic organs remains unclear. In addition, plants synthesize another anionic lipid glucuronosyldiacylglycerol (GlcADG) during phosphorus starvation, but its role in plant cells is not elucidated yet. To understand the functional relationships among PG, SQDG, and GlcADG, we characterized several Arabidopsis thaliana mutants defective in biosynthesis of these lipids. The mutants completely lacking both PG and SQDG biosynthesis in plastids showed developmental defects of roots, hypocotyls, and embryos in addition to leaves, which suggests that these lipids are pleiotropically required for the development of both photosynthetic and non-photosynthetic organs. Furthermore, our analysis revealed that SQDG, but not GlcADG, is essential for complementing the role of PG, particularly in photosynthesis under PG-deficient conditions such as phosphorus starvation.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Diglicerídeos/metabolismo , Glicolipídeos/metabolismo , Fosfatidilgliceróis/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Cloroplastos/genética , Cianobactérias/genética , Cianobactérias/metabolismo , Galactolipídeos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Hipocótilo/citologia , Hipocótilo/crescimento & desenvolvimento , Hipocótilo/metabolismo , Mutação , Células Vegetais/metabolismo , Folhas de Planta/citologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Sementes/citologia , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
13.
BMC Plant Biol ; 21(1): 253, 2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34082706

RESUMO

BACKGROUND: Root hydraulic conductance is primarily determined by the conductance of living tissues to radial water flow. Plasma membrane intrinsic proteins (PIPs) in root cortical cells are important for plants to take up water and are believed to be directly involved in cell growth. RESULTS: In this study, we found that constitutive overexpression of the poplar root-specific gene PtoPIP1;1 in Arabidopsis accelerated bolting and flowering. At the early stage of the developmental process, PtoPIP1;1 OE Arabidopsis exhibited faster cell growth in both leaves and roots. The turgor pressure of plants was correspondingly increased in PtoPIP1;1 OE Arabidopsis, and the water status was changed. At the same time, the expression levels of flowering-related genes (CRY1, CRY2 and FCA) and hub genes in the regulatory networks underlying floral timing (FT and SOC1) were significantly upregulated in OE plants, while the floral repressor FLC gene was significantly downregulated. CONCLUSIONS: Taken together, the results of our study indicate that constitutive overexpression of PtoPIP1;1 in Arabidopsis accelerates bolting and flowering through faster cell growth in both the leaf and root at an early stage of the developmental process. The autonomous pathway of flowering regulation may be executed by monitoring developmental age. The increase in turgor and changes in water status with PtoPIP1;1 overexpression play a role in promoting cell growth.


Assuntos
Aquaporinas/fisiologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Proteínas de Plantas/metabolismo , Populus/metabolismo , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Regulação da Expressão Gênica de Plantas/fisiologia , Folhas de Planta/citologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Raízes de Plantas/citologia , Raízes de Plantas/crescimento & desenvolvimento , Transpiração Vegetal , Plantas Geneticamente Modificadas , Populus/genética
14.
Genome Biol ; 22(1): 151, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33975629

RESUMO

BACKGROUND: The developmental gradient in monocot leaves has been exploited to uncover leaf developmental gene expression programs and chloroplast biogenesis processes. However, the relationship between the two is barely understood, which limits the value of transcriptome data to understand the process of chloroplast development. RESULTS: Taking advantage of the developmental gradient in the bread wheat leaf, we provide a simultaneous quantitative analysis for the development of mesophyll cells and of chloroplasts as a cellular compartment. This allows us to generate the first biologically-informed gene expression map of this leaf, with the entire developmental gradient from meristematic to fully differentiated cells captured. We show that the first phase of plastid development begins with organelle proliferation, which extends well beyond cell proliferation, and continues with the establishment and then the build-up of the plastid genetic machinery. The second phase is marked by the development of photosynthetic chloroplasts which occupy the available cellular space. Using a network reconstruction algorithm, we predict that known chloroplast gene expression regulators are differentially involved across those developmental stages. CONCLUSIONS: Our analysis generates both the first wheat leaf transcriptional map and one of the most comprehensive descriptions to date of the developmental history of chloroplasts in higher plants. It reveals functionally distinct plastid and chloroplast development stages, identifies processes occurring in each of them, and highlights our very limited knowledge of the earliest drivers of plastid biogenesis, while providing a basis for their future identification.


Assuntos
Cloroplastos/genética , Perfilação da Expressão Gênica , Fotossíntese/genética , Folhas de Planta/genética , Triticum/genética , Proliferação de Células/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Genomas de Plastídeos , Folhas de Planta/citologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Análise de Componente Principal , Biossíntese de Proteínas/genética , Triticum/citologia
15.
Plant Cell Rep ; 40(7): 1171-1179, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33948685

RESUMO

KEY MESSAGE: Microwounding pre-treatment facilitates agroinfiltration and transient gene expression in hard-to-agroinfiltrate citrus varieties. Agrobacterium infiltration is a widely used method for transient expression studies in plants, but this method is not used extensively in citrus because of its low efficiency. In this study, we developed an easy, cheap, and reliable agroinfiltration method for transient gene expression in citrus. A microneedle roller was used to create microscopic wounds in the leaf epidermis to facilitate agroinfiltration. Several optimization parameters were explored in this study, including the density of wounds per cm2 of abaxial leaf area, the leaf maturity grade, the effect of the Agrobacterium strain, and the length of the incubation period. Increasing the density of wounds on the leaf surface had a positive effect on transient expression. Higher transient expression levels were observed in well-expanded young leaves in comparison with older leaves. The Agrobacterium strain GV2260 was the most suitable to express a large amount of recombinant protein, and an eight- to ten-day incubation period resulted in the highest expression. Endoplasmic reticulum and cytoskeleton-targeted GFP were both successfully localized, confirming that this protocol can be used for protein subcellular localization in citrus. Finally, up to 100 ng of GFP per milligram of agroinfiltrated leaf tissue was estimated to be expressed using this method. This protocol was tested for GFP expression in five different citrus varieties with no significant statistical differences among them. This simple and easy method can speed up functional genomic studies in citrus and may be applied to other recalcitrant species with extensive epidermal cuticular wax.


Assuntos
Agrobacterium/genética , Citrus/genética , Folhas de Planta/genética , Proteínas Recombinantes/genética , DNA Bacteriano/administração & dosagem , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Microscopia Confocal , Folhas de Planta/citologia , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas/genética , Proteínas Recombinantes/metabolismo , Transfecção/métodos
16.
Nat Commun ; 12(1): 2739, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-34016974

RESUMO

In addition to conspicuous large mesophyll chloroplasts, where most photosynthesis occurs, small epidermal chloroplasts have also been observed in plant leaves. However, the functional significance of this small organelle remains unclear. Here, we present evidence that Arabidopsis epidermal chloroplasts control the entry of fungal pathogens. In entry trials, specialized fungal cells called appressoria triggered dynamic movement of epidermal chloroplasts. This movement is controlled by common regulators of mesophyll chloroplast photorelocation movement, designated as the epidermal chloroplast response (ECR). The ECR occurs when the PEN2 myrosinase-related higher-layer antifungal system becomes ineffective, and blockage of the distinct steps of the ECR commonly decreases preinvasive nonhost resistance against fungi. Furthermore, immune components were preferentially localized to epidermal chloroplasts, contributing to antifungal nonhost resistance in the pen2 background. Our findings reveal that atypical small chloroplasts act as defense-related motile organelles by specifically positioning immune components in the plant epidermis, which is the first site of contact between the plant and pathogens. Thus, this work deepens our understanding of the functions of epidermal chloroplasts.


Assuntos
Arabidopsis/imunologia , Cloroplastos/imunologia , Resistência à Doença/imunologia , Doenças das Plantas/imunologia , Epiderme Vegetal/imunologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Auxilinas/genética , Auxilinas/metabolismo , Proteínas de Cloroplastos/genética , Proteínas de Cloroplastos/metabolismo , Cloroplastos/metabolismo , Colletotrichum/imunologia , Colletotrichum/patogenicidade , Interações Hospedeiro-Patógeno/imunologia , Magnaporthe/imunologia , Magnaporthe/patogenicidade , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Mutação , N-Glicosil Hidrolases/genética , N-Glicosil Hidrolases/metabolismo , Doenças das Plantas/microbiologia , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Epiderme Vegetal/microbiologia , Folhas de Planta/citologia , Folhas de Planta/imunologia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Pseudomonas syringae/imunologia , Pseudomonas syringae/patogenicidade
17.
Plant Cell Environ ; 44(8): 2455-2465, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33974719

RESUMO

The leaf intercellular airspace is a tortuous environment consisting of cells of different shapes, packing densities, and orientation, all of which have an effect on the travelling distance of molecules from the stomata to the mesophyll cell surfaces. Tortuosity, the increase in displacement over the actual distance between two points, is typically defined as encompassing the whole leaf airspace, but heterogeneity in pore dimensions and orientation between the spongy and palisade mesophyll likely result in heterogeneity in tortuosity along different axes and would predict longer traveling distance along the path of least tortuosity, such as vertically within the columnar cell matrix of the palisade layer. Here, we compare a previously established geometric method to a random walk approach, novel for this analysis in plant leaves, in four different Eucalyptus species. The random walk method allowed us to quantify directional tortuosity across the whole leaf profile, and separately for the spongy and palisade mesophyll. For all species tortuosity was higher in the palisade mesophyll than the spongy mesophyll and horizontal (parallel to the epidermis) tortuosity was consistently higher than vertical (from epidermis to epidermis) tortuosity. We demonstrate that a random walk approach improves on previous geometric approaches and is valuable for investigating CO2 and H2 O transport within leaves.


Assuntos
Eucalyptus/anatomia & histologia , Folhas de Planta/anatomia & histologia , Folhas de Planta/citologia , Ar , Isótopos de Carbono/análise , Parede Celular/ultraestrutura , Eucalyptus/ultraestrutura , Imageamento Tridimensional , Células do Mesofilo/química , Microscopia Eletrônica de Varredura , Células Vegetais , Folhas de Planta/ultraestrutura , Estômatos de Plantas/anatomia & histologia
18.
PLoS Genet ; 17(5): e1009292, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33970916

RESUMO

The plastochron, the time interval between the formation of two successive leaves, is an important determinant of plant architecture. We genetically and phenotypically investigated many-noded dwarf (mnd) mutants in barley. The mnd mutants exhibited a shortened plastochron and a decreased leaf blade length, and resembled previously reported plastochron1 (pla1), pla2, and pla3 mutants in rice. In addition, the maturation of mnd leaves was accelerated, similar to pla mutants in rice. Several barley mnd alleles were derived from three genes-MND1, MND4, and MND8. Although MND4 coincided with a cytochrome P450 family gene that is a homolog of rice PLA1, we clarified that MND1 and MND8 encode an N-acetyltransferase-like protein and a MATE transporter-family protein, which are respectively orthologs of rice GW6a and maize BIGE1 and unrelated to PLA2 or PLA3. Expression analyses of the three MND genes revealed that MND1 and MND4 were expressed in limited regions of the shoot apical meristem and leaf primordia, but MND8 did not exhibit a specific expression pattern around the shoot apex. In addition, the expression levels of the three genes were interdependent among the various mutant backgrounds. Genetic analyses using the double mutants mnd4mnd8 and mnd1mnd8 indicated that MND1 and MND4 regulate the plastochron independently of MND8, suggesting that the plastochron in barley is controlled by multiple genetic pathways involving MND1, MND4, and MND8. Correlation analysis between leaf number and leaf blade length indicated that both traits exhibited a strong negative association among different genetic backgrounds but not in the same genetic background. We propose that MND genes function in the regulation of the plastochron and leaf growth and revealed conserved and diverse aspects of plastochron regulation via comparative analysis of barley and rice.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Hordeum/crescimento & desenvolvimento , Hordeum/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/genética , Alelos , Sistemas CRISPR-Cas/genética , Divisão Celular , Hordeum/citologia , Mutação , Oryza/genética , Fenótipo , Células Vegetais , Folhas de Planta/citologia , Fatores de Tempo
19.
PLoS One ; 16(5): e0251625, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34010344

RESUMO

Numerous long-term, free-air plant growth facilities currently explore vegetation responses to the ongoing climate change in northern latitudes. Open top chamber (OTC) experiments as well as the experimental set-ups with active warming focus on many facets of plant growth and performance, but information on morphological alterations of plant cells is still scarce. Here we compare the effects of in-situ warming on leaf epidermal cell expansion in dwarf birch, Betula nana in Finland, Greenland, and Poland. The localities of the three in-situ warming experiments represent contrasting regions of B. nana distribution, with the sites in Finland and Greenland representing the current main distribution in low and high Arctic, respectively, and the continental site in Poland as a B. nana relict Holocene microrefugium. We quantified the epidermal cell lateral expansion by microscopic analysis of B. nana leaf cuticles. The leaves were produced in paired experimental treatment plots with either artificial warming or ambient temperature. At all localities, the leaves were collected in two years at the end of the growing season to facilitate between-site and within-site comparison. The measured parameters included the epidermal cell area and circumference, and using these, the degree of cell wall undulation was calculated as an Undulation Index (UI). We found enhanced leaf epidermal cell expansion under experimental warming, except for the extremely low temperature Greenland site where no significant difference occurred between the treatments. These results demonstrate a strong response of leaf growth at individual cell level to growing season temperature, but also suggest that in harsh conditions other environmental factors may limit this response. Our results provide evidence of the relevance of climate warming for plant leaf maturation and underpin the importance of studies covering large geographical scales.


Assuntos
Betula/crescimento & desenvolvimento , Folhas de Planta/crescimento & desenvolvimento , Betula/citologia , Mudança Climática , Células Epidérmicas/citologia , Finlândia , Groenlândia , Temperatura Alta , Meteorologia , Folhas de Planta/citologia , Polônia , Estações do Ano
20.
Plant J ; 107(1): 237-255, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33884686

RESUMO

Stromules are dynamic membrane-bound tubular structures that emanate from plastids. Stromule formation is triggered in response to various stresses and during plant development, suggesting that stromules may have physiological and developmental roles in these processes. Despite the possible biological importance of stromules and their prevalence in green plants, their exact roles and formation mechanisms remain unclear. To explore these issues, we obtained Arabidopsis thaliana mutants with excess stromule formation in the leaf epidermis by microscopy-based screening. Here, we characterized one of these mutants, stromule biogenesis altered 1 (suba1). suba1 forms plastids with severely altered morphology in a variety of non-mesophyll tissues, such as leaf epidermis, hypocotyl epidermis, floral tissues, and pollen grains, but apparently normal leaf mesophyll chloroplasts. The suba1 mutation causes impaired chloroplast pigmentation and altered chloroplast ultrastructure in stomatal guard cells, as well as the aberrant accumulation of lipid droplets and their autophagic engulfment by the vacuole. The causal defective gene in suba1 is TRIGALACTOSYLDIACYLGLYCEROL5 (TGD5), which encodes a protein putatively involved in the endoplasmic reticulum (ER)-to-plastid lipid trafficking required for the ER pathway of thylakoid lipid assembly. These findings suggest that a non-mesophyll-specific mechanism maintains plastid morphology. The distinct mechanisms maintaining plastid morphology in mesophyll versus non-mesophyll plastids might be attributable, at least in part, to the differential contributions of the plastidial and ER pathways of lipid metabolism between mesophyll and non-mesophyll plastids.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/citologia , Proteínas de Transporte/fisiologia , Células do Mesofilo/fisiologia , Plastídeos/fisiologia , Arabidopsis/crescimento & desenvolvimento , Cloroplastos/ultraestrutura , Flores/citologia , Células do Mesofilo/ultraestrutura , Mutação , Epiderme Vegetal/citologia , Epiderme Vegetal/genética , Folhas de Planta/citologia , Folhas de Planta/genética , Raízes de Plantas/citologia , Estômatos de Plantas , Plantas Geneticamente Modificadas , Plastídeos/ultraestrutura
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