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1.
Plant J ; 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34587339

RESUMO

The architecture and genetic diversity of mitogenome (mtDNA) are largely unknown in cultivated soybean (Glycine max), which is domesticated from the wild progenitor, Glycine soja, 5000 years ago. Here, we de novo assembled the mitogenome of the cultivar 'Williams 82' (Wm82_mtDNA) with Illumina PE300 deep sequencing data, and verified it with polymerase chain reaction (PCR) and Southern blot analyses. Wm82_mtDNA maps as two autonomous circular chromosomes (370 871-bp Chr-m1 and 62 661-bp Chr-m2). Its structure is extensively divergent from that of the mono-chromosomal mitogenome reported in the landrace 'Aiganhuang' (AGH_mtDNA). Synteny analysis showed that the structural variations (SVs) between two genomes are mainly attributed to ectopic and illegitimate recombination. Moreover, Wm82_mtDNA and AGH_mtDNA each possess six and four specific regions, which are absent in their counterparts and likely result from differential sequence-loss events. Mitogenome SV was further studied in 39 wild and 182 cultivated soybean accessions distributed world-widely with PCR/Southern analyses or a comparable in silico analysis. The results classified both wild and cultivated soybeans into five cytoplasmic groups, named as GSa-GSe and G1-G5; 'Williams 82' and 'Aiganhuang' belong to G1 and G5, respectively. Notably, except for members in GSe and G5, all accessions carry a bi-chromosomal mitogenome with a common Chr-m2. Phylogenetic analyses based on mtDNA structures and chloroplast gene sequences both inferred that G1-G3, representing >90% of cultigens, likely inherited cytoplasm from the ancestor of domestic soybean, while G4 and G5 likely inherited cytoplasm from wild soybeans carrying GSa- and GSe-like cytoplasm through interspecific hybridization, offering new insights into soybean cultivation history.

2.
J Plant Physiol ; 264: 153487, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34358944

RESUMO

AtCYP38, a thylakoid lumen localized immunophilin, is found to be essential for photosystem II assembly and maintenance, but how AtCYP38 functions in chloroplast remains unknown. Based on previous functional studies and its crystal structure, we hypothesize that AtCYP38 should function via binding its targets or cofactors in the thylakoid lumen. To identify potential interacting proteins of AtCYP38, we first adopted ATTED-II and STRING web-tools, and found 12 proteins functionally related to AtCYP38. We then screened a yeast two-hybrid library including an Arabidopsis genome wide cDNA with different domain of AtCYP38, and five thylakoid lumen-localized targets were identified. In order to specifically search interacting proteins of AtCYP38 in the thylakoid lumen, we generated a yeast two-hybrid mini library including the thylakoid lumenal proteins and lumenal fractions of thylakoid membrane proteins, and we obtained six thylakoid membrane proteins and nine thylakoid lumenal proteins as interacting proteins of AtCYP38. The interactions between AtCYP38 and several potential targets were further confirmed via pull-down and co-immunoprecipitation assays. Together, a couple of new potential candidate interacting proteins of AtCYP38 were identified, and the results will lay a foundation for unveiling the regulatory mechanisms in photosynthesis by AtCYP38.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Ciclofilinas/metabolismo , Proteínas de Arabidopsis/fisiologia , Ciclofilinas/fisiologia , Imunoprecipitação , Complexo de Proteína do Fotossistema II/metabolismo , Domínios e Motivos de Interação entre Proteínas , Técnicas do Sistema de Duplo-Híbrido
3.
Theor Appl Genet ; 134(11): 3661-3674, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34319425

RESUMO

KEY MESSAGE: Identification and functional analysis of the male sterile gene MS6 in Glycine max. Soybean (Glycine max (L.) Merr.) is an important crop providing vegetable oil and protein. The male sterility-based hybrid breeding is a promising method for improving soybean yield to meet the globally growing demand. In this research, we identified a soybean genic male sterile locus, MS6, by combining the bulked segregant analysis sequencing method and the map-based cloning technology. MS6, highly expressed in anther, encodes an R2R3 MYB transcription factor (GmTDF1-1) that is homologous to Tapetal Development and Function 1, a key factor for anther development in Arabidopsis and rice. In male sterile ms6 (Ames1), the mutant allele contains a missense mutation, leading to the 76th leucine substituted by histidine in the DNA binding domain of GmTDF1-1. The expression of soybean MS6 under the control of the AtTDF1 promoter could rescue the male sterility of attdf1 but ms6 could not. Additionally, ms6 overexpression in wild-type Arabidopsis did not affect anther development. These results evidence that GmTDF1-1 is a functional TDF1 homolog and L76H disrupts its function. Notably, GmTDF1-1 shows 92% sequence identity with another soybean protein termed as GmTDF1-2, whose active expression also restored the fertility of attdf1. However, GmTDF1-2 is constitutively expressed at a very low level in soybean, and therefore, not able to compensate for the MS6 deficiency. Analysis of the TDF1-involved anther development regulatory pathway showed that expressions of the genes downstream of TDF1 are significantly suppressed in ms6, unveiling that GmTDF1-1 is a core transcription factor regulating soybean anther development.

4.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281206

RESUMO

The basic helix-loop-helix (bHLH) transcription factor family is one of the largest transcription factor gene families in Arabidopsis thaliana, and contains a bHLH motif that is highly conserved throughout eukaryotic organisms. Members of this family have two conserved motifs, a basic DNA binding region and a helix-loop-helix (HLH) region. These proteins containing bHLH domain usually act as homo- or heterodimers to regulate the expression of their target genes, which are involved in many physiological processes and have a broad range of functions in biosynthesis, metabolism and transduction of plant hormones. Although there are a number of articles on different aspects to provide detailed information on this family in plants, an overall summary is not available. In this review, we summarize various aspects of related studies that provide an overview of insights into the pleiotropic regulatory roles of these transcription factors in plant growth and development, stress response, biochemical functions and the web of signaling networks. We then provide an overview of the functional profile of the bHLH family and the regulatory mechanisms of other proteins.


Assuntos
Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sequência de Aminoácidos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Expressão Gênica , Genoma de Planta , Sequências Hélice-Alça-Hélice , Família Multigênica , Filogenia , Proteínas de Plantas/genética , Análise de Sequência de DNA/métodos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
5.
Plant Commun ; 2(3): 100178, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-34027392

RESUMO

Manganese (Mn) serves as an essential cofactor for many enzymes in various compartments of a plant cell. Allocation of Mn among various organelles thus plays a central role in Mn homeostasis to support metabolic processes. We report the identification of a Golgi-localized Mn transporter (named PML3) that is essential for rapid cell elongation in young tissues such as emerging leaves and the pollen tube. In particular, the pollen tube defect in the pml3 loss-of-function mutant caused severe reduction in seed yield, a critical agronomic trait. Further analysis suggested that a loss of pectin deposition in the pollen tube might cause the pollen tube to burst and slow its elongation, leading to decreased male fertility. As the Golgi apparatus serves as the major hub for biosynthesis and modification of cell-wall components, PML3 may function in Mn homeostasis of this organelle, thereby controlling metabolic and/or trafficking processes required for pectin deposition in rapidly elongating cells.

6.
Plant Cell Environ ; 44(5): 1580-1595, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33495993

RESUMO

Nitrate (NO3 - ) is a source of plant nutrients and osmolytes, but its delivery machineries under osmotic and low-nutrient stress remain largely unknown. Here, we report that AtICln, an Arabidopsis homolog of the nucleotide-sensitive chloride-conductance regulatory protein family (ICln), is involved in response to osmotic and low-NO3 - stress. The gene AtICln, encoding plasma membrane-anchored proteins, was upregulated by various osmotic stresses, and its disruption impaired plant tolerance to osmotic stress. Compared with the wild type, the aticln mutant retained lower anions, particularly NO3 - , and its growth retardation was not rescued by NO3 - supply under osmotic stress. Interestingly, this mutant also displayed growth defects under low-NO3 stress, which were accompanied by decreases in NO3 - accumulation, suggesting that AtICln may facilitate the NO3 - accumulation under NO3 - deficiency. Moreover, the low-NO3 - hypersensitive phenotype of aticln mutant was overridden by the overexpression of NRT1.1, an important NO3 - transporter in Arabidopsis low-NO3 - responses. Further genetic analysis in the plants with altered activity of AtICln and NRT1.1 indicated that AtICln and NRT1.1 play a compensatory role in maintaining NO3 - homeostasis under low-NO3 - environments. These results suggest that AtICln is involved in cellular NO3 - accumulation and thus determines osmotic adjustment and low-NO3 - tolerance in plants.


Assuntos
Adaptação Fisiológica , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Nitratos/metabolismo , Osmose , Homologia de Sequência de Aminoácidos , Proteínas de Transporte de Ânions/metabolismo , Membrana Celular/metabolismo , Cloretos/metabolismo , Teste de Complementação Genética , Mutação/genética , Concentração Osmolar , Pressão Osmótica , Fenótipo , Proteínas de Plantas/metabolismo , Frações Subcelulares/metabolismo
7.
Plant Commun ; 1(5): 100094, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-33367259

RESUMO

Chlorophyll (Chl) is essential for photosynthetic reactions and chloroplast development. While the enzymatic pathway for Chl biosynthesis is well established, the regulatory mechanism underlying the homeostasis of Chl levels remains largely unknown. In this study, we identified CBD1 (Chlorophyll Biosynthetic Defect1), which functions in the regulation of chlorophyll biosynthesis. The CBD1 gene was expressed specifically in green tissues and its protein product was embedded in the thylakoid membrane. Furthermore, CBD1 was precisely co-expressed and functionally correlated with GUN5 (Genome Uncoupled 5). Analysis of chlorophyll metabolic intermediates indicated that cbd1 and cbd1gun5 mutants over-accumulated magnesium protoporphyrin IX (Mg-Proto IX). In addition, the cbd1 mutant thylakoid contained less Mg than the wild type not only as a result of lower Chl content, but also implicating CBD1 in Mg transport. This was supported by the finding that CBD1 complemented a Mg2+ uptake-deficient Salmonella strain under low Mg conditions. Taken together, these results indicate that CBD1 functions synergistically with CHLH/GUN5 in Mg-Proto IX processing, and may serve as a Mg-transport protein to maintain Mg homeostasis in the chloroplast.

8.
Int J Mol Sci ; 21(21)2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33120933

RESUMO

Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns (DAMPs) that are derived from precursor proteins PROPEPs and perceived by a pair of leucine-rich repeat receptor-like kinases (LRR-RLKs), PEPR1 and PEPR2, to enhance innate immunity and to inhibit root growth in Arabidopsis thaliana. In this study, we show that Arabidopsis Pep1 inhibits the root growth by interfering with pH signaling, as acidic condition increased, but neutral and alkaline conditions decreased the Pep1 effect on inhibiting the root growth. The perception of Pep1 to PEPRs activated the plasma membrane-localized H+-ATPases (PM H+-ATPases) -the pump proton in plant cell-to extrude the protons into apoplast, and induced an overly acidic environment in apoplastic space, which further promoted the cell swelling in root apex and inhibited root growth. Furthermore, we revealed that pump proton AUTOINHIBITED H+-ATPase 2 (AHA2) physically interacted with PEPR2 and served downstream of the Pep1-PEPRs signaling pathway to regulate Pep1-induced protons extrusion and root growth inhibition. In conclusion, this study demonstrates a previously unrecognized signaling crosstalk between Pep1 and pH signaling to regulate root growth.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Proteínas Serina-Treonina Quinases/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Transativadores/metabolismo , Alarminas/metabolismo , Arabidopsis/metabolismo , Membrana Celular/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Concentração de Íons de Hidrogênio , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Transdução de Sinais
9.
Int J Mol Sci ; 21(13)2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32605179

RESUMO

Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns (DAMPs) that are perceived by a pair of receptor-like kinases, PEPR1 and PEPR2, to enhance innate immunity and induce the growth inhibition of root in Arabidopsis thaliana. In this study, we show that PEPR1 and PEPR2 function vitally in roots to regulate the root immune responses when treating the roots with bacterial pathogen Pst DC3000. PEPR2, rather than PEPR1, played a predominant role in the perception of Pep1 in the roots and further triggered a strong ROS accumulation-the substance acts as an antimicrobial agent or as a secondary messenger in plant cells. Consistently, seedlings mutating two major ROS-generating enzyme genes, respiratory burst oxidase homologs D and F (RBOHD and RBOHF), abolished the root ROS accumulation and impaired the growth inhibition of the roots induced by Pep1. Furthermore, we revealed that botrytis-induced kinase 1 (BIK1) physically interacted with PEPRs and RBOHD/F, respectively, and served downstream of the Pep1-PEPRs signaling pathway to regulate Pep1-induced ROS production and root growth inhibition. In conclusion, this study demonstrates a previously unrecognized signaling crosstalk between Pep1 and ROS signaling to regulate root immune response and root growth.


Assuntos
Alarminas/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Fragmentos de Peptídeos/farmacologia , Imunidade Vegetal/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Alarminas/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/imunologia , Raízes de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo
10.
Plant Commun ; 1(1): 100013, 2020 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33404541

RESUMO

Membrane transport processes are indispensable for many aspects of plant physiology including mineral nutrition, solute storage, cell metabolism, cell signaling, osmoregulation, cell growth, and stress responses. Completion of genome sequencing in diverse plant species and the development of multiple genomic tools have marked a new era in understanding plant membrane transport at the mechanistic level. Genes coding for a galaxy of pumps, channels, and carriers that facilitate various membrane transport processes have been identified while multiple approaches are developed to dissect the physiological roles as well as to define the transport capacities of these transport systems. Furthermore, signaling networks dictating the membrane transport processes are established to fully understand the regulatory mechanisms. Here, we review recent research progress in the discovery and characterization of the components in plant membrane transport that take advantage of plant genomic resources and other experimental tools. We also provide our perspectives for future studies in the field.


Assuntos
Membrana Celular/metabolismo , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Genética Reversa/métodos , Transporte Biológico , Membrana Celular/genética , Genoma de Planta , Genômica/métodos , Família Multigênica , Proteínas de Plantas/genética , Plantas/genética , Transdução de Sinais
11.
Plant Physiol ; 181(2): 743-761, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31350362

RESUMO

Plants cope with aluminum (Al) toxicity by secreting organic acids (OAs) into the apoplastic space, which is driven by proton (H+) pumps. Here, we show that mutation of vacuolar H+-translocating adenosine triphosphatase (H+-ATPase) subunit a2 (VHA-a2) and VHA-a3 of the vacuolar H+-ATPase enhances Al resistance in Arabidopsis (Arabidopsis thaliana). vha-a2 vha-a3 mutant plants displayed less Al sensitivity with less Al accumulation in roots compared to wild-type plants when grown under excessive Al3+ Interestingly, in response to Al3+ exposure, plants showed decreased vacuolar H+ pump activity and reduced expression of VHA-a2 and VHA-a3, which were accompanied by increased plasma membrane H+ pump (PM H+-ATPase) activity. Genetic analysis of plants with altered PM H+-ATPase activity established a correlation between Al-induced increase in PM H+-ATPase activity and enhanced Al resistance in vha-a2 vha-a3 plants. We determined that external OAs, such as malate and citrate whose secretion is driven by PM H+-ATPase, increased with PM H+-ATPase activity upon Al stress. On the other hand, elevated secretion of malate and citrate in vha-a2 vha-a3 root exudates appeared to be independent of OAs metabolism and tolerance of phosphate starvation but was likely related to impaired vacuolar sequestration. These results suggest that coordination of vacuolar H+-ATPase and PM H+-ATPase dictates the distribution of OAs into either the vacuolar lumen or the apoplastic space that, in turn, determines Al tolerance capacity in plants.


Assuntos
Alumínio/toxicidade , Arabidopsis/metabolismo , Ácidos Carboxílicos/metabolismo , Raízes de Plantas/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Alumínio/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Pirofosfatase Inorgânica/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Raízes de Plantas/efeitos dos fármacos , ATPases Vacuolares Próton-Translocadoras/genética
12.
Plant Cell ; 31(8): 1767-1787, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31123046

RESUMO

Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns that are perceived by the receptor-like kinases, PEPR1 and PEPR2, to enhance innate immunity and to inhibit root growth in Arabidopsis (Arabidopsis thaliana). Here, we show that Arabidopsis Pep1 inhibits root growth in a PEPR2-dependent manner, which is accompanied by swelling epidermal and cortex cells and root hair formation in the transition zone (TZ). These Pep1-induced changes were mimicked by exogenous auxin application and were suppressed in the auxin perception mutants transport inhibitor response1 (tir1) and tir1 afb1 afb2 Pep1-induced auxin accumulation in the TZ region preceded cell expansion in roots. Because local auxin distribution depends on PIN-type auxin transporters, we examined Pep1-PEPR-induced root growth inhibition in several pin mutants and found that pin2 was highly sensitive but pin3 was less sensitive to Pep1. The pin2 pin3 double mutant was as sensitive to Pep1 treatment as wild-type plants. Pep1 reduced the abundance of PIN2 in the plasma membrane through activating endocytosis while increasing PIN3 expression in the TZ, leading to changes in local auxin distribution and inhibiting root growth. These results suggest that Pep-PEPR signaling undergoes crosstalk with auxin accumulation to control cell expansion and differentiation in roots during immune responses.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Transporte Biológico/genética , Transporte Biológico/fisiologia , Membrana Celular/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Transativadores/genética , Transativadores/metabolismo
13.
Plant Cell Environ ; 42(2): 673-687, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30255504

RESUMO

Multiple transporters and channels mediate cation transport across the plasma membrane and tonoplast to regulate ionic homeostasis in plant cells. However, much less is known about the molecular function of transporters that facilitate cation transport in other organelles such as Golgi. We report here that Arabidopsis KEA4, KEA5, and KEA6, members of cation/proton antiporters-2 (CPA2) superfamily were colocalized with the known Golgi marker, SYP32-mCherry. Although single kea4,5,6 mutants showed similar phenotype as the wild type under various conditions, kea4/5/6 triple mutants showed hypersensitivity to low pH, high K+ , and high Na+ and displayed growth defects in darkness, suggesting that these three KEA-type transporters function redundantly in controlling etiolated seedling growth and ion homeostasis. Detailed analysis indicated that the kea4/5/6 triple mutant exhibited cell wall biosynthesis defect during the rapid etiolated seedling growth and under high K+ /Na+ condition. The cell wall-derived pectin homogalacturonan (GalA)3 partially suppressed the growth defects and ionic toxicity in the kea4/5/6 triple mutants when grown in the dark but not in the light conditions. Together, these data support the hypothesis that the Golgi-localized KEAs play key roles in the maintenance of ionic and pH homeostasis, thereby facilitating Golgi function in cell wall biosynthesis during rapid etiolated seedling growth and in coping with high K+ /Na+ stress.


Assuntos
Antiporters/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Complexo de Golgi/metabolismo , Plântula/crescimento & desenvolvimento , Arabidopsis/metabolismo , Escuridão , Homeostase , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real
14.
Plant Physiol ; 179(2): 640-655, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30552198

RESUMO

Vacuolar storage of phosphate (Pi) is essential for Pi homeostasis in plants. Recent studies have identified a family of vacuolar Pi transporters, VPTs (PHT5s), responsible for vacuolar sequestration of Pi. We report here that both VPT1 and VPT3 contribute to cytosol-to-vacuole Pi partitioning. Although VPT1 plays a predominant role, VPT3 is particularly important when VPT1 is absent. Our data suggested that the vpt1 vpt3 double mutant was more defective in Pi homeostasis than the vpt1 single mutant, as indicated by Pi accumulation capacity, vacuolar Pi influx, subcellular Pi allocation, and plant adaptability to changing Pi status. The remaining member of the VPT family, VPT2 (PHT5;2), did not appear to contribute to Pi homeostasis in such assays. Particularly interesting is the finding that the vpt1 vpt3 double mutant was impaired in reproductive development with shortened siliques and impaired seed set under sufficient Pi, and this phenotype was not found in the vpt1 vpt2 and vpt2 vpt3 double mutants. Measurements of Pi contents revealed Pi over-accumulation in the floral organs of vpt1 vpt3 as compared with the wild type. Further analysis identified excess Pi in the pistil as inhibitory to pollen tube growth, and thus seed yield, in the mutant plants. Reducing the Pi levels in culture medium or mutation of PHO1, a Pi transport protein responsible for root-shoot transport, restored the seed set of vpt1 vpt3 Thus, VPTs, through their function in vacuolar Pi sequestration, control the fine-tuning of systemic Pi allocation, which is particularly important for reproductive development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Transporte de Fosfato/metabolismo , Fosfatos/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Flores/efeitos dos fármacos , Flores/metabolismo , Homeostase , Mutação , Proteínas de Transporte de Fosfato/genética , Fosfatos/toxicidade , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Vacúolos/metabolismo
15.
Front Plant Sci ; 9: 720, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29971071

RESUMO

Soybean (Glycine max) seed yields rely on the efficiency of photosynthesis, which is poorly understood in soybean. Chlorophyll, the major light harvesting pigment, is crucial for chloroplast biogenesis and photosynthesis. Magnesium chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX in the first committed and key regulatory step of chlorophyll biosynthesis. It consists of three types of subunits, ChlI, ChlD, and ChlH. To gain a better knowledge of chlorophyll biosynthesis in soybean, we analyzed soybean Mg-chelatase subunits and their encoding genes. Soybean genome harbors 4 GmChlI genes, 2 GmChlD genes, and 3 GmChlH genes, likely evolved from two rounds of gene duplication events. The qRT-PCR analysis revealed that GmChlI, GmChlD, and GmChlH genes predominantly expressed in photosynthetic tissues, but the expression levels among paralogs are different. In silicon promoter analyses revealed these genes harbor different cis-regulatory elements in their promoter regions, suggesting they could differentially respond to various environmental and developmental signals. Subcellular localization analyses illustrated that GmChlI, GmChlD, and GmChlH isoforms are all localized in chloroplast, consistent with their functions. Yeast two hybrid and bimolecular fluorescence complementation (BiFC) assays showed each isoform has a potential to be assembled into the Mg-chelatase holocomplex. We expressed each GmChlI, GmChlD, and GmChlH isoform in Arabidopsis corresponding mutants, and results showed that 4 GmChlI and 2 GmChlD isoforms and GmChlH1 could rescue the severe phenotype of Arabidopsis mutants, indicating that they maintain normal biochemical functions in vivo. However, GmChlH2 and GmChlH3 could not completely rescue the chlorotic phenotype of Arabidopsis gun5-2 mutant, suggesting that the functions of these two proteins could be different from GmChlH1. Considering the differences shown on primary sequences, biochemical functions, and gene expression profiles, we conclude that the paralogs of each soybean Mg-chelatase subunit have diverged more or less during evolution. Soybean could have developed a complex regulatory mechanism to control chlorophyll content to adapt to different developmental and environmental situations.

16.
Plant Cell ; 30(5): 1132-1146, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29716993

RESUMO

The plant elicitor peptides (Peps), a family of damage/danger-associated molecular patterns (DAMPs), are perceived by two receptors, PEPR1 and PEPR2, and contribute to plant defense against pathogen attack and abiotic stress. Here, we show that the Peps-PEPR signaling pathway functions in stomatal immunity by activating guard cell anion channels in Arabidopsis thaliana The mutant plants lacking both PEPR1 and PEPR2 (pepr1 pepr2) displayed enhanced bacterial growth after being sprayed with Pseudomonas syringae pv tomato (Pst) DC3000, but not after pathogen infiltration into leaves, implicating PEPR function in stomatal immunity. Indeed, synthetic Arabidopsis Peps (AtPeps) effectively induced stomatal closure in wild-type but not pepr1 pepr2 mutant leaves, suggesting that the AtPeps-PEPR signaling pathway triggers stomatal closure. Consistent with this finding, patch-clamp recording revealed AtPep1-induced activation of anion channels in the guard cells of wild-type but not pepr1 pepr2 mutant plants. We further identified two guard cell-expressed anion channels, SLOW ANION CHANNEL1 (SLAC1) and its homolog SLAH3, as functionally overlapping components responsible for AtPep1-induced stomatal closure. The slac1 slah3 double mutant, but not slac1 or slah3 single mutants, failed to respond to AtPep1 in stomatal closure assays. Interestingly, disruption of OPEN STOMATA1 (OST1), an essential gene for abscisic acid-triggered stomatal closure, did not affect the AtPep1-induced anion channel activity and stomatal response. Together, these results illustrate a DAMP-triggered signaling pathway that, unlike the flagellin22-FLAGELLIN-SENSITIVE2 pathway, triggers stomata immunity through an OST1-independent mechanism.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Peptídeos/metabolismo , Estômatos de Plantas/metabolismo , Proteínas Quinases/metabolismo
17.
Mol Plant ; 11(7): 943-954, 2018 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-29734003

RESUMO

Manganese (Mn) is an essential catalytic metal in the Mn-cluster that oxidizes water to produce oxygen during photosynthesis. However, the transport protein(s) responsible for Mn2+ import into the chloroplast remains unknown. Here, we report the characterization of Arabidopsis CMT1 (Chloroplast Manganese Transporter 1), an evolutionarily conserved protein in the Uncharacterized Protein Family 0016 (UPF0016), that is required for manganese accumulation into the chloroplast. CMT1 is expressed primarily in green tissues, and its encoded product is localized in the inner envelope membrane of the chloroplast. Disruption of CMT1 in the T-DNA insertional mutant cmt1-1 resulted in stunted plant growth, defective thylakoid stacking, and severe reduction of photosystem II complexes and photosynthetic activity. Consistent with reduced oxygen evolution capacity, the mutant chloroplasts contained less manganese than the wild-type ones. In support of its function as a Mn transporter, CMT1 protein supported the growth and enabled Mn2+ accumulation in the yeast cells of Mn2+-uptake deficient mutant (Δsmf1). Taken together, our results indicate that CMT1 functions as an inner envelope Mn transporter responsible for chloroplast Mn2+ uptake.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , Manganês/metabolismo , Tilacoides/metabolismo , Proteínas de Arabidopsis/genética , Transporte Biológico , DNA (Citosina-5-)-Metiltransferases/genética , Regulação da Expressão Gênica de Plantas , Homeostase , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/crescimento & desenvolvimento
18.
PLoS One ; 11(10): e0165018, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27764209

RESUMO

The effect of cropping system on the distribution of organic carbon (OC) and nitrogen (N) in soil aggregates has not been well addressed, which is important for understanding the sequestration of OC and N in agricultural soils. We analyzed the distribution of OC and N associated with soil aggregates in three unfertilized cropping systems in a 27-year field experiment: continuously cropped alfalfa, continuously cropped wheat and a legume-grain rotation. The objectives were to understand the effect of cropping system on the distribution of OC and N in aggregates and to examine the relationships between the changes in OC and N stocks in total soils and in aggregates. The cropping systems increased the stocks of OC and N in total soils (0-40 cm) at mean rates of 15.6 g OC m-2 yr-1 and 1.2 g N m-2 yr-1 relative to a fallow control. The continuous cropping of alfalfa produced the largest increases at the 0-20 cm depth. The OC and N stocks in total soils were significantly correlated with the changes in the >0.053 mm aggregates. 27-year of cropping increased OC stocks in the >0.053 mm size class of aggregates and N stocks in the >0.25 mm size class but decreased OC stocks in the <0.053 mm size class and N stocks in the <0.25 mm size class. The increases in OC and N stocks in these aggregates accounted for 99.5 and 98.7% of the total increases, respectively, in the continuous alfalfa system. The increases in the OC and N stocks associated with the >0.25 mm aggregate size class accounted for more than 97% of the total increases in the continuous wheat and the legume-grain rotation systems. These results suggested that long-term cropping has the potential to sequester OC and N in soils and that the increases in soil OC and N stocks were mainly due to increases associated with aggregates >0.053 mm.


Assuntos
Agricultura/métodos , Carbono/análise , Produtos Agrícolas/crescimento & desenvolvimento , Nitrogênio/análise , Monitoramento Ambiental , Fabaceae/crescimento & desenvolvimento , Medicago sativa/crescimento & desenvolvimento , Solo/química , Triticum/crescimento & desenvolvimento
19.
Proc Natl Acad Sci U S A ; 112(5): 1613-8, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25605904

RESUMO

In earlier studies we have identified FKBP20-2 and CYP38 as soluble proteins of the chloroplast thylakoid lumen that are required for the formation of photosystem II supercomplexes (PSII SCs). Subsequent work has identified another potential candidate functional in SC formation (PSB27). We have followed up on this possibility and isolated mutants defective in the PSB27 gene. In addition to lack of PSII SCs, mutant plants were severely stunted when cultivated with light of variable intensity. The stunted growth was associated with lower PSII efficiency and defective starch accumulation. In response to high light exposure, the mutant plants also displayed enhanced ROS production, leading to decreased biosynthesis of anthocyanin. Unexpectedly, we detected a second defect in the mutant, namely in CP26, an antenna protein known to be required for the formation of PSII SCs that has been linked to state transitions. Lack of PSII SCs was found to be independent of PSB27, but was due to a mutation in the previously described cp26 gene that we found had no effect on light adaptation. The present results suggest that PSII SCs, despite being required for state transitions, are not associated with acclimation to changing light intensity. Our results are consistent with the conclusion that PSB27 plays an essential role in enabling plants to adapt to fluctuating light intensity through a mechanism distinct from photosystem II supercomplexes and state transitions.


Assuntos
Adaptação Fisiológica , Proteínas de Arabidopsis/fisiologia , Luz , Complexo de Proteína do Fotossistema II/fisiologia , Antocianinas/metabolismo , Proteínas de Arabidopsis/genética , Eletroforese em Gel de Poliacrilamida , Mutação , Complexo de Proteína do Fotossistema II/genética , Espécies Reativas de Oxigênio/metabolismo , Amido/biossíntese
20.
Proc Natl Acad Sci U S A ; 110(40): 16247-52, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-24043802

RESUMO

Photosystem II (PSII) reaction center protein D1 is synthesized as a precursor (pD1) with a short C-terminal extension. The pD1 is processed to mature D1 by carboxyl-terminal peptidase A to remove the C-terminal extension and form active protein. Here we report functional characterization of the Arabidopsis gene encoding D1 C-terminal processing enzyme (AtCtpA) in the chloroplast thylakoid lumen. Recombinant AtCtpA converted pD1 to mature D1 and a mutant lacking AtCtpA retained all D1 in precursor form, confirming that AtCtpA is solely responsible for processing. As with cyanobacterial ctpa, a knockout Arabidopsis atctpa mutant was lethal under normal growth conditions but was viable with sucrose under low-light conditions. Viable plants, however, showed deficiencies in PSII and thylakoid stacking. Surprisingly, unlike its cyanobacterial counterpart, the Arabidopsis mutant retained both monomer and dimer forms of the PSII complexes that, although nonfunctional, contained both the core and extrinsic subunits. This mutant was also essentially devoid of PSII supercomplexes, providing an unexpected link between D1 maturation and supercomplex assembly. A knock-down mutant expressing about 2% wild-type level of AtCtpA showed normal growth under low light but was stunted and accumulated pD1 under high light, indicative of delayed C-terminal processing. Although demonstrating the functional significance of C-terminal D1 processing in PSII biogenesis, our study reveals an unsuspected link between D1 maturation and PSII supercomplex assembly in land plants, opening an avenue for exploring the mechanism for the association of light-harvesting complexes with the PSII core complexes.


Assuntos
Arabidopsis/metabolismo , Endopeptidases/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Complexo de Proteína do Fotossistema II/biossíntese , Complexo de Proteína do Fotossistema II/fisiologia , Eletroforese em Gel de Poliacrilamida , Endopeptidases/genética , Fluorescência , Técnicas de Silenciamento de Genes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tilacoides/metabolismo
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