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1.
Nat Commun ; 11(1): 4577, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917881

RESUMO

Nuclear pore complexes (NPCs) are important for cellular functions beyond nucleocytoplasmic trafficking, including genome organization and gene expression. This multi-faceted nature and the slow turnover of NPC components complicates investigations of how individual nucleoporins act in these diverse processes. To address this question, we apply an Auxin-Induced Degron (AID) system to distinguish roles of basket nucleoporins NUP153, NUP50 and TPR. Acute depletion of TPR causes rapid and pronounced changes in transcriptomic profiles. These changes are dissimilar to shifts observed after loss of NUP153 or NUP50, but closely related to changes caused by depletion of mRNA export receptor NXF1 or the GANP subunit of the TRanscription-EXport-2 (TREX-2) mRNA export complex. Moreover, TPR depletion disrupts association of TREX-2 subunits (GANP, PCID2, ENY2) to NPCs and results in abnormal RNA transcription and export. Our findings demonstrate a unique and pivotal role of TPR in gene expression through TREX-2- and/or NXF1-dependent mRNA turnover.


Assuntos
Exodesoxirribonucleases/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Poro Nuclear/metabolismo , Fosfoproteínas/metabolismo , RNA Mensageiro/metabolismo , Linhagem Celular , Regulação da Expressão Gênica , Humanos , Ácidos Indolacéticos/metabolismo , Proteínas Nucleares , Proteínas de Transporte Nucleocitoplasmático , Transporte Proteico , Proteínas de Ligação a RNA , Transcriptoma , Dedos de Zinco
2.
PLoS Biol ; 18(8): e3000830, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32810128

RESUMO

Plants are attacked by herbivores, which often specialize on different tissues, and in response, have evolved sophisticated resistance strategies that involve different types of chemical defenses frequently targeted to different tissues. Most known phytohormones have been implicated in regulating these defenses, with jasmonates (JAs) playing a pivotal role in complex regulatory networks of signaling interactions, often generically referred to as "cross talk." The newly identified class of phytohormones, strigolactones (SLs), known to regulate the shoot architecture, remain unstudied with regard to plant-herbivore interactions. We explored the role of SL signaling in resistance to a specialist weevil (Trichobaris mucorea) herbivore of the native tobacco, Nicotiana attenuata, that attacks the root-shoot junction (RSJ), the part of the plant most strongly influenced by alterations in SL signaling (increased branching). As SL signaling shares molecular components, such as the core F-box protein MORE AXILLARY GROWTH 2 (MAX2), with another new class of phytohormones, the karrikins (KARs), which promote seed germination and seedling growth, we generated transformed lines, individually silenced in the expression of NaMAX2, DWARF 14 (NaD14: the receptor for SL) and CAROTENOID CLEAVAGE DIOXYGENASE 7 (NaCCD7: a key enzyme in SL biosynthesis), and KARRIKIN INSENSITIVE 2 (NaKAI2: the KAR receptor). The mature stems of all transgenic lines impaired in the SL, but not the KAR signaling pathway, overaccumulated anthocyanins, as did the stems of plants attacked by the larvae of weevil, which burrow into the RSJs to feed on the pith of N. attenuata stems. T. mucorea larvae grew larger in the plants silenced in the SL pathway, but again, not in the KAI2-silenced plants. These phenotypes were associated with elevated JA and auxin (indole-3-acetic acid [IAA]) levels and significant changes in the accumulation of defensive compounds, including phenolamides and nicotine. The overaccumulation of phenolamides and anthocyanins in the SL pathway-silenced plants likely resulted from antagonism between the SL and JA pathway in N. attenuata. We show that the repressors of SL signaling, suppressor of max2-like (NaSMXL6/7), and JA signaling, jasmonate zim-domain (NaJAZs), physically interact, promoting NaJAZb degradation and releasing JASMONATE INSENSITIVE 1 (JIN1/MYC2) (NaMYC2), a critical transcription factor promoting JA responses. However, the increased performance of T. mucorea larvae resulted from lower pith nicotine levels, which were inhibited by increased IAA levels in SL pathway-silenced plants. This inference was confirmed by decapitation and auxin transport inhibitor treatments that decreased pith IAA and increased nicotine levels. In summary, SL signaling tunes specific sectors of specialized metabolism in stems, such as phenylpropanoid and nicotine biosynthesis, by tailoring the cross talk among phytohormones, including JA and IAA, to mediate herbivore resistance of stems. The metabolic consequences of the interplay of SL, JA, and IAA signaling revealed here could provide a mechanism for the commonly observed pattern of herbivore tolerance/resistance trade-offs.


Assuntos
Herbivoria/fisiologia , Interações Hospedeiro-Parasita , Lactonas/metabolismo , Caules de Planta/metabolismo , Caules de Planta/parasitologia , Transdução de Sinais , Tabaco/metabolismo , Tabaco/parasitologia , Animais , Antocianinas/metabolismo , Ciclopentanos/metabolismo , Ácidos Indolacéticos/metabolismo , Larva , Metabolômica , Oxilipinas/metabolismo , Proteínas de Plantas/metabolismo , Interferência de RNA , Gorgulhos/fisiologia
3.
Nat Commun ; 11(1): 3914, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764676

RESUMO

Cell polarity is fundamental to the development of both eukaryotes and prokaryotes, yet the mechanisms behind its formation are not well understood. Here we found that, phytohormone auxin-induced, sterol-dependent nanoclustering of cell surface transmembrane receptor kinase 1 (TMK1) is critical for the formation of polarized domains at the plasma membrane (PM) during the morphogenesis of cotyledon pavement cells (PC) in Arabidopsis. Auxin-induced TMK1 nanoclustering stabilizes flotillin1-associated ordered nanodomains, which in turn promote the nanoclustering of ROP6 GTPase that acts downstream of TMK1 to regulate cortical microtubule organization. In turn, cortical microtubules further stabilize TMK1- and flotillin1-containing nanoclusters at the PM. Hence, we propose a new paradigm for polarity formation: A diffusive signal triggers cell polarization by promoting cell surface receptor-mediated nanoclustering of signaling components and cytoskeleton-mediated positive feedback that reinforces these nanodomains into polarized domains.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citologia , Arabidopsis/metabolismo , Polaridade Celular/fisiologia , Ácidos Indolacéticos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/química , Membrana Celular/metabolismo , Polaridade Celular/genética , Metabolismo dos Lipídeos , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Modelos Biológicos , Proteínas Monoméricas de Ligação ao GTP/química , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Mutação , Reguladores de Crescimento de Planta/metabolismo , Plantas Geneticamente Modificadas , Agregados Proteicos , Estabilidade Proteica , Proteínas Serina-Treonina Quinases/química , Transdução de Sinais
4.
PLoS One ; 15(7): e0235795, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645115

RESUMO

To investigate the growth, physiological changes and mechanism of drought resistance of Camellia oleifera GWu-2 under drought stress conditions, changes in the main growth and physiological indices of GWu-2 under different water gradients were studied. Factor analysis was used to study the differences between indicators under different water gradients, and correlation analysis was implemented to analyze the relationship between different factors. We observed that the growth state, enzyme secretion, stomatal morphology and leaf osmotic adjustment substances were significantly affected by drought stress. In particular, increases in leaf abscisic acid (ABA), indole acetic acid (IAA) and methyl jasmonate (MeJA) contents under drought stress were negatively correlated with the stomatal opening degree, and the ratio of ZR/GA3 was significantly correlated with the growth and physiological indicators of GWu-2, indicating that different hormones respond differently to drought stress and have different functions in the growth regulation and drought resistance of GWu-2. We concluded that the drought resistance mechanism of GWu-2 was controlled by maintaining root growth to obtain the necessary water, increasing the contents of osmotic substances of leaves to maintain water holding capacity, reducing the transpiration of water by increasing leaf ABA, IAA and MeJA content to close stomata and reducing the damage caused by drought by increasing the activity of superoxide dismutase (SOD).


Assuntos
Aclimatação , Camellia/fisiologia , Ácido Abscísico/metabolismo , Acetatos/metabolismo , Camellia/crescimento & desenvolvimento , Ciclopentanos/metabolismo , Secas , Ácidos Indolacéticos/metabolismo , Oxilipinas/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Estômatos de Plantas/crescimento & desenvolvimento , Estômatos de Plantas/fisiologia , Estresse Fisiológico , Água/metabolismo
5.
PLoS One ; 15(7): e0236530, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32706831

RESUMO

Apple trees grafted on different rootstock types, including vigorous rootstock (VR), dwarfing interstock (DIR), and dwarfing self-rootstock (DSR), are widely planted in production, but the molecular determinants of tree branch architecture growth regulation induced by rootstocks are still not well known. In this study, the branch growth phenotypes of three combinations of 'Fuji' apple trees grafted on different rootstocks (VR: Malus baccata; DIR: Malus baccata/T337; DSR: T337) were investigated. The VR trees presented the biggest branch architecture. The results showed that the sugar content, sugar metabolism-related enzyme activities, and hormone content all presented obvious differences in the tender leaves and buds of apple trees grafted on these rootstocks. Transcriptomic profiles of the tender leaves adjacent to the top buds allowed us to identify genes that were potentially involved in signaling pathways that mediate the regulatory mechanisms underlying growth differences. In total, 3610 differentially expressed genes (DEGs) were identified through pairwise comparisons. The screened data suggested that sugar metabolism-related genes and complex hormone regulatory networks involved the auxin (IAA), cytokinin (CK), abscisic acid (ABA) and gibberellic acid (GA) pathways, as well as several transcription factors, participated in the complicated growth induction process. Overall, this study provides a framework for analysis of the molecular mechanisms underlying differential tree branch growth of apple trees grafted on different rootstocks.


Assuntos
Regulação da Expressão Gênica de Plantas , Malus/genética , Transdução de Sinais/genética , Açúcares/metabolismo , Ácido Abscísico/análise , Ácido Abscísico/metabolismo , Cromatografia Líquida de Alta Pressão , Citocininas/análise , Citocininas/metabolismo , Flores/genética , Flores/metabolismo , Giberelinas/análise , Giberelinas/metabolismo , Ácidos Indolacéticos/análise , Ácidos Indolacéticos/metabolismo , Malus/crescimento & desenvolvimento , Fenótipo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/fisiologia , RNA de Plantas/genética , RNA de Plantas/metabolismo , Açúcares/análise , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , alfa-Glucosidases/genética , alfa-Glucosidases/metabolismo
6.
Nat Commun ; 11(1): 3508, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665554

RESUMO

Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits; among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration.


Assuntos
Compostos Heterocíclicos com 3 Anéis/metabolismo , Ácidos Indolacéticos/metabolismo , Lactonas/metabolismo , Ervilhas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Ervilhas/genética , Reguladores de Crescimento de Planta/metabolismo
7.
Gene ; 758: 144942, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32640309

RESUMO

WUSCHEL-related homeobox4 (WOX4) plays important roles in vascular formation and adventitious root (AR) development. Here, we cloned the WOX4 from the AR of Larix kaempferi, whose cDNA is 1452 bp in length and encodes 483 amino acids. LkWOX4 is mainly expressed in the layer formation area of the stem at 10 days after cutting and its expression levels in the middles and ends of the ARs were higher than that in the AR tips. The fused protein LkWOX4-GFP localized in the nucleus. The heterologous overexpression of LkWOX4 in 84 K poplar significantly increased AR numbers and decreased AR lengths. In LkWOX4 plants, the endogenous jasmonic acid and abscisic acid contents significantly decreased in stems, while the auxin, jasmonic acid and abscisic acid contents significantly increased in ARs. RNA-Seq of those LkWOX4 overexpression poplar plants showed that the expression of plant hormone signaling genes (ARF2, ARF3, ARF7 and ARF18), rooting-related transcription factors (WOX5, LBD29 and SCR) and root development-related genes (CYCD3, GRF1 and TAA1) were affected. Moreover, we found that LkWOX4 interacts with LkPAT18, LkACBP6, and LkCIP7 using yeast two hybrid screening. Thus, we found LkWOX4 involves in the AR initiation and development, which might be regulated through the IAA, JA and ABA signaling pathways.


Assuntos
Proteínas de Homeodomínio/genética , Larix/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Organogênese Vegetal/genética , Fatores de Transcrição/genética , Ácido Abscísico/metabolismo , Clonagem Molecular , Ciclopentanos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos/metabolismo , Larix/genética , Meristema/genética , Oxilipinas/metabolismo , Transdução de Sinais/genética
8.
Proc Natl Acad Sci U S A ; 117(28): 16667-16677, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601177

RESUMO

Plants are known for their outstanding capacity to recover from various wounds and injuries. However, it remains largely unknown how plants sense diverse forms of injury and canalize existing developmental processes into the execution of a correct regenerative response. Auxin, a cardinal plant hormone with morphogen-like properties, has been previously implicated in the recovery from diverse types of wounding and organ loss. Here, through a combination of cellular imaging and in silico modeling, we demonstrate that vascular stem cell death obstructs the polar auxin flux, much alike rocks in a stream, and causes it to accumulate in the endodermis. This in turn grants the endodermal cells the capacity to undergo periclinal cell division to repopulate the vascular stem cell pool. Replenishment of the vasculature by the endodermis depends on the transcription factor ERF115, a wound-inducible regulator of stem cell division. Although not the primary inducer, auxin is required to maintain ERF115 expression. Conversely, ERF115 sensitizes cells to auxin by activating ARF5/MONOPTEROS, an auxin-responsive transcription factor involved in the global auxin response, tissue patterning, and organ formation. Together, the wound-induced auxin accumulation and ERF115 expression grant the endodermal cells stem cell activity. Our work provides a mechanistic model for wound-induced stem cell regeneration in which ERF115 acts as a wound-inducible stem cell organizer that interprets wound-induced auxin maxima.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Ácidos Indolacéticos/metabolismo , Regeneração , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Divisão Celular , Autorrenovação Celular , Regulação da Expressão Gênica de Plantas , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Fatores de Transcrição/genética
9.
Ecotoxicol Environ Saf ; 202: 110854, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32585484

RESUMO

Atrazine as a kind of herbicide could cause damage to the sensitive plants. Though plant growth promoting rhizobacteria (PGPR) have been proven with the potential to enhance the resistance of plants against various abiotic stresses, whether it could alleviate phytotoxicity caused by atrazine is sill unclear. In present study, the effects of strain Pseudomonas chlororaphis PAS18, a kind of PGPR enable to produce indole-3-acetic acid (IAA), on the growth and physiological responses of Pennisetum americanum (L.) K.Schum seedlings were investigated under three different levels (0, 20 and 100 mg kg-1) of atrazine in pot experiment. The results suggest that strain PAS18 could alleviate the growth and physiological interference caused by 20 mg kg-1 of atrazine. Physiological analysis showed strain PAS18 could further decrease the damaged extent of photosystem II, superoxide radical level and malondialdehyde content of test plant via up-regulating psbA expression, enhancing superoxide dismutase activity and reducing atrazine accumulation in the test plant. Moreover, ion flux measurements suggest that IAA could alleviate the Ca2+ exflux state of the test plant which caused by atrazine stress. Hence, it is plausible that strain PAS18 could alleviate atrazine-induced stress to P. americanum by enhancing the photosystem II repair and antioxidant defense ability as well as balancing the Ca2+ flux.


Assuntos
Atrazina/toxicidade , Ácidos Indolacéticos/metabolismo , Pennisetum/fisiologia , Pseudomonas chlororaphis/fisiologia , Antioxidantes/metabolismo , Atrazina/metabolismo , Tolerância a Medicamentos , Herbicidas/metabolismo , Malondialdeído/metabolismo , Pennisetum/efeitos dos fármacos , Fotossíntese , Pseudomonas chlororaphis/metabolismo , Plântula/efeitos dos fármacos , Estresse Fisiológico
10.
Nat Commun ; 11(1): 2965, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32528082

RESUMO

Trajectories of cellular ontogeny are tightly controlled and often involve feedback-regulated molecular antagonism. For example, sieve element differentiation along developing protophloem cell files of Arabidopsis roots requires two antagonistic regulators of auxin efflux. Paradoxically, loss-of-function in either regulator triggers similar, seemingly stochastic differentiation failures of individual sieve element precursors. Here we show that these patterning defects are distinct and non-random. They can be explained by auxin-dependent bistability that emerges from competition for auxin between neighboring cells. This bistability depends on the presence of an auxin influx facilitator, and can be triggered by either flux enhancement or repression. Our results uncover a hitherto overlooked aspect of auxin uptake, and highlight the contributions of local auxin influx, efflux and biosynthesis to protophloem formation. Moreover, the combined experimental-modeling approach suggests that without auxin efflux homeostasis, auxin influx interferes with coordinated differentiation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citologia , Arabidopsis/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Transformação Genética/genética
11.
Proc Natl Acad Sci U S A ; 117(26): 15322-15331, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541049

RESUMO

Wound healing in plant tissues, consisting of rigid cell wall-encapsulated cells, represents a considerable challenge and occurs through largely unknown mechanisms distinct from those in animals. Owing to their inability to migrate, plant cells rely on targeted cell division and expansion to regenerate wounds. Strict coordination of these wound-induced responses is essential to ensure efficient, spatially restricted wound healing. Single-cell tracking by live imaging allowed us to gain mechanistic insight into the wound perception and coordination of wound responses after laser-based wounding in Arabidopsis root. We revealed a crucial contribution of the collapse of damaged cells in wound perception and detected an auxin increase specific to cells immediately adjacent to the wound. This localized auxin increase balances wound-induced cell expansion and restorative division rates in a dose-dependent manner, leading to tumorous overproliferation when the canonical TIR1 auxin signaling is disrupted. Auxin and wound-induced turgor pressure changes together also spatially define the activation of key components of regeneration, such as the transcription regulator ERF115. Our observations suggest that the wound signaling involves the sensing of collapse of damaged cells and a local auxin signaling activation to coordinate the downstream transcriptional responses in the immediate wound vicinity.


Assuntos
Arabidopsis/fisiologia , Ácidos Indolacéticos/metabolismo , Células Vegetais/fisiologia , Raízes de Plantas/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Divisão Celular , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/antagonistas & inibidores , Cinurenina/farmacologia , Lasers , Ftalimidas/farmacologia , Células Vegetais/efeitos dos fármacos , Regeneração/efeitos dos fármacos , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Triazóis/farmacologia
12.
Proc Natl Acad Sci U S A ; 117(27): 16027-16034, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32571946

RESUMO

Puzzle-shaped pavement cells provide a powerful model system to investigate the cellular and subcellular processes underlying complex cell-shape determination in plants. To better understand pavement cell-shape acquisition and the role of auxin in this process, we focused on the spirals of young stomatal lineage ground cells of Arabidopsis leaf epidermis. The predictability of lobe formation in these cells allowed us to demonstrate that the auxin response gradient forms within the cells of the spiral and fluctuates based on the particular stage of lobe development. We revealed that specific localization of auxin transporters at the different membranes of these young cells changes during the course of lobe formation, suggesting that these fluctuating auxin response gradients are orchestrated via auxin transport to control lobe formation and determine pavement cell shape.


Assuntos
Arabidopsis/metabolismo , Forma Celular/efeitos dos fármacos , Forma Celular/fisiologia , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacologia , Proteínas de Arabidopsis , Transporte Biológico , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Estômatos de Plantas/metabolismo
13.
Nat Commun ; 11(1): 2170, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358503

RESUMO

Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Citocininas/metabolismo , Resistência à Doença/genética , Ácidos Indolacéticos/metabolismo , Proteínas de Membrana/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/metabolismo , Transcriptoma/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Parede Celular/química , Parede Celular/metabolismo , Endossomos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Complexo de Golgi/metabolismo , Proteínas de Membrana/genética , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas/metabolismo , Plasmodioforídeos/patogenicidade , Via Secretória/genética , Solo , Proteínas de Transporte Vesicular/metabolismo
14.
Nat Commun ; 11(1): 2143, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358569

RESUMO

Allosteric regulation is protein activation by effector binding at a site other than the active site. Here, we show via X-ray structural analysis of gibberellin 2-oxidase 3 (GA2ox3), and auxin dioxygenase (DAO), that such a mechanism maintains hormonal homeostasis in plants. Both enzymes form multimers by interacting via GA4 and indole-3-acetic acid (IAA) at their binding interface. Via further functional analyses we reveal that multimerization of these enzymes gradually proceeds with increasing GA4 and IAA concentrations; multimerized enzymes have higher specific activities than monomer forms, a system that should favour the maintenance of homeostasis for these phytohormones. Molecular dynamic analysis suggests a possible mechanism underlying increased GA2ox3 activity by multimerization-GA4 in the interface of oligomerized GA2ox3s may be able to enter the active site with a low energy barrier. In summary, homeostatic systems for maintaining GA and IAA levels, based on a common allosteric mechanism, appear to have developed independently.


Assuntos
Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Cristalografia por Raios X , Regulação da Expressão Gênica de Plantas , Simulação de Dinâmica Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
15.
Chemosphere ; 256: 127157, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470740

RESUMO

Microcystins released by cyanobacteria affect crop growth and productivity, and even food safety. Plant hormones play a vital role in regulating growth, development and stress response in plants. Therefore, we studied the response of hormones including abscisic acid (ABA), indole-3-acetic acid (IAA), Zeatin (ZT) and gibberellin (GA3) as well as hormone balances (IAA/ABA, ZT/ABA and GA/ABA) to cyanobacterial extract containing microcystins (1, 10, 100 and 1000 µg/L) during stress and recovery periods. Low concentration microcystins (1 µg/L) promoted growth of rice seedlings by increasing levels of IAA, ZT and GA3 and maintaining hormone balances. In addition, the up-regulation of OsYUCCA1 increased IAA level in rice roots by promoting IAA biosynthesis. High concentrations microcystins (10, 100 or1000 µg/L) inhibited growth of rice seedlings by reducing levels of IAA, ZT and GA3 and ratios of IAA/ABA, ZT/ABA and GA/ABA due to increased ABA level. The increase in ABA in rice seedlings induced by high concentrations MCs was resulted from up-regulation of OsNCED1, OsNCED3, OsNCED4 and OsZEP to enhance ABA biosynthesis, and was controlled by up-regulating expression levels of OsABAox1-3 for enhancing ABA catabolism as negative feedback. The highest concentration of MCs (1000 µg/L) caused irreversible damage to metabolisms of IAA and ABA, partly resulting in unrecoverable inhibition on rice growth. All results demonstrate that "low-concentration promotion and high-concentration inhibition" of microcystins was associated with changes in hormone levels and balances by affecting their metabolisms, and could be helpful for guiding agricultural irrigation with microcystin contaminated water.


Assuntos
Cianobactérias/metabolismo , Microcistinas/toxicidade , Oryza/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Plântula/metabolismo , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Extratos Vegetais , Raízes de Plantas/metabolismo , Zeatina/metabolismo
16.
Proc Natl Acad Sci U S A ; 117(23): 12784-12790, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32461365

RESUMO

Fruit development normally occurs after pollination and fertilization; however, in parthenocarpic plants, the ovary grows into the fruit without pollination and/or fertilization. Parthenocarpy has been recognized as a highly attractive agronomic trait because it could stabilize fruit yield under unfavorable environmental conditions. Although natural parthenocarpic varieties are useful for breeding Solanaceae plants, their use has been limited, and little is known about their molecular and biochemical mechanisms. Here, we report a parthenocarpic eggplant mutant, pad-1, which accumulates high levels of auxin in the ovaries. Map-based cloning showed that the wild-type (WT) Pad-1 gene encoded an aminotransferase with similarity to Arabidopsis VAS1 gene, which is involved in auxin homeostasis. Recombinant Pad-1 protein catalyzed the conversion of indole-3-pyruvic acid (IPyA) to tryptophan (Trp), which is a reverse reaction of auxin biosynthetic enzymes, tryptophan aminotransferases (TAA1/TARs). The RNA level of Pad-1 gene increased during ovary development and reached its highest level at anthesis stage in WT. This suggests that the role of Pad-1 in WT unpollinated ovary is to prevent overaccumulation of IAA resulting in precocious fruit-set. Furthermore, suppression of the orthologous genes of Pad-1 induced parthenocarpic fruit development in tomato and pepper plants. Our results demonstrated that the use of pad-1 genes would be powerful tools to improve fruit production of Solanaceae plants.


Assuntos
Ácidos Indolacéticos/metabolismo , Mutação com Perda de Função , Partenogênese , Proteínas de Plantas/genética , Solanum melongena/genética , Transaminases/genética , Flores/genética , Flores/metabolismo , Flores/fisiologia , Homeostase , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Solanum melongena/fisiologia , Transaminases/metabolismo
17.
Nat Commun ; 11(1): 2277, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385295

RESUMO

Cullin RING-type E3 ubiquitin ligases SCFTIR1/AFB1-5 and their AUX/IAA targets perceive the phytohormone auxin. The F-box protein TIR1 binds a surface-exposed degron in AUX/IAAs promoting their ubiquitylation and rapid auxin-regulated proteasomal degradation. Here, by adopting biochemical, structural proteomics and in vivo approaches we unveil how flexibility in AUX/IAAs and regions in TIR1 affect their conformational ensemble allowing surface accessibility of degrons. We resolve TIR1·auxin·IAA7 and TIR1·auxin·IAA12 complex topology, and show that flexible intrinsically disordered regions (IDRs) in the degron's vicinity, cooperatively position AUX/IAAs on TIR1. We identify essential residues at the TIR1 N- and C-termini, which provide non-native interaction interfaces with IDRs and the folded PB1 domain of AUX/IAAs. We thereby establish a role for IDRs in modulating auxin receptor assemblies. By securing AUX/IAAs on two opposite surfaces of TIR1, IDR diversity supports locally tailored positioning for targeted ubiquitylation, and might provide conformational flexibility for a multiplicity of functional states.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Proteólise , Receptores de Superfície Celular/metabolismo , Proteínas de Arabidopsis/química , Sítios de Ligação , Proteínas Intrinsicamente Desordenadas/química , Simulação de Dinâmica Molecular , Mutação/genética , Filogenia , Domínios Proteicos , Ubiquitinação
18.
Gene ; 750: 144725, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32360839

RESUMO

The small auxin-up RNA (SAUR) family plays a vital role in the regulation of plant growth and development. We identified 80 MdSAUR genes in this study. Phylogenetic analysis indicated that the SAUR proteins from Arabidopsis, rice, and apple were divided into six groups. Of the 80 MdSAURs, 71 were randomly distributed along the 17 chromosomes, while the remaining genes were located along unassigned scafoolds. Among them, a comprehensive overview of SAUR gene family is presented, including gene structures, chromosome locations, duplication and selection pressure analyses, synteny and promoter analyses, and protein interaction. The expression profiles based on microarray data found that 80 genes showed increased expression levels in at least one tissue including seed, seedling, root, stem, leaf, flower, fruit 100daa, and harvested fruit. MdSAUR7 possibly regulate the development of flower organs, and MdSAUR15, MdSAUR24, and MdSAUR80 promote the growth of fruits by regulating cell division. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated the expression levels of 79 MdSAUR genes in leaves under exogenous IAA treatment. MdSAUR4, MdSAUR22, MdSAUR37, MdSAUR38, MdSAUR49, and MdSAUR54 were up-regulated after IAA treatment compared with the control, indicating that they may play specific roles in the IAA signaling transduction pathway. This work provided a foundation for further investigations for the functional analyses of SAURs in apple.


Assuntos
Genes de Plantas/genética , Ácidos Indolacéticos/metabolismo , Malus/genética , Arabidopsis/genética , Frutas/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Família Multigênica/genética , Filogenia , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , RNA/genética , Plântula/genética
19.
Proc Natl Acad Sci U S A ; 117(16): 9112-9121, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32253321

RESUMO

Plant auxin response factor (ARF) transcription factors are an important class of key transcriptional modulators in auxin signaling. Despite the well-studied roles of ARF transcription factors in plant growth and development, it is largely unknown whether, and how, ARF transcription factors may be involved in plant resistance to pathogens. We show here that two fijiviruses (double-stranded RNA viruses) utilize their proteins to disturb the dimerization of OsARF17 and repress its transcriptional activation ability, while a tenuivirus (negative-sense single-stranded RNA virus) directly interferes with the DNA binding activity of OsARF17. These interactions impair OsARF17-mediated antiviral defense. OsARF17 also confers resistance to a cytorhabdovirus and was directly targeted by one of the viral proteins. Thus, OsARF17 is the common target of several very different viruses. This suggests that OsARF17 plays a crucial role in plant defense against different types of plant viruses, and that these viruses use independently evolved viral proteins to target this key component of auxin signaling and facilitate infection.


Assuntos
Regulação da Expressão Gênica de Plantas/imunologia , Oryza/imunologia , Proteínas de Plantas/metabolismo , Vírus de Plantas/imunologia , Vírus de RNA/imunologia , Fatores de Transcrição/metabolismo , Resistência à Doença/genética , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Ácidos Indolacéticos/metabolismo , Mutação , Oryza/genética , Oryza/virologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/virologia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Vírus de Plantas/metabolismo , Plantas Geneticamente Modificadas , Multimerização Proteica/imunologia , Vírus de RNA/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais/imunologia , Tabaco/genética , Tabaco/metabolismo , Tabaco/virologia , Fatores de Transcrição/genética , Proteínas Virais/imunologia , Proteínas Virais/metabolismo
20.
Int J Mol Sci ; 21(2)2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32284503

RESUMO

Allotriploid poplar has a prominent vegetative growth advantage that impacts dramatically on lumber yield. The growth regulation is complex which involves abundant genes, metabolic and signaling pathways, while the information about the functional control process is very little. We used high-throughput sequencing and physiological index measurement to obtain a global overview of differences between allotriploid and diploid Populus. The genes related to plant growth advantage show a higher expression compared to diploid, and most of them are revolved around hormones, photosynthesis and product accumulation. Thus, allotriploid Populus showed more efficient photosynthesis, carbon fixation, sucrose and starch synthesis, and metabolism as well as augmented biosynthesis of auxin, cytokinin, and gibberellin. These data enable the connection of metabolic processes, signaling pathways, and specific gene activity, which will underpin the development of network models to elucidate the process of triploid Populus advantage growth.


Assuntos
Fotossíntese/genética , Reguladores de Crescimento de Planta/metabolismo , Populus/genética , Transdução de Sinais , Ciclo do Carbono/genética , Citocininas/metabolismo , Perfilação da Expressão Gênica , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Ácidos Indolacéticos/metabolismo , Folhas de Planta , Populus/crescimento & desenvolvimento , Populus/fisiologia , Populus/ultraestrutura , Amido/metabolismo , Sacarose/metabolismo , Triploidia
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