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1.
J Agric Food Chem ; 67(29): 8186-8190, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31272146

RESUMO

Indole-3-acetic acid (IAA) is considered the most common and important naturally occurring auxin in plants and a major regulator of plant growth and development. In this study, an aldehyde dehydrogenase AldH from Escherichia coli was found to convert indole-3-acetylaldehyde into IAA. Then we established an artificial pathway in engineered E. coli for microbial production of IAA from glucose. The overall pathway includes the upstream pathway from glucose to L-tryptophan and the downstream pathway from L-tryptophan to IAA. To our knowledge, this is the first report on the biosynthesis of IAA directly from a renewable carbon source. The study described here shows the way for the development of a beneficial microbe for biosynthesis of auxin and promoting plant growth in the future.


Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Ácidos Indolacéticos/metabolismo , Vias Biossintéticas , Engenharia Genética , Glucose/metabolismo , Triptofano/metabolismo
2.
Nat Commun ; 10(1): 2904, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31266952

RESUMO

Plant survival necessitates constant monitoring of fluctuating light and balancing growth demands with adaptive responses, tasks mediated via interconnected sensing and signaling networks. Photoreceptor phytochrome B (phyB) and plastidial retrograde signaling metabolite methylerythritol cyclodiphosphate (MEcPP) are evolutionarily conserved sensing and signaling components eliciting responses through unknown connection(s). Here, via a suppressor screen, we identify two phyB mutant alleles that revert the dwarf and high salicylic acid phenotypes of the high MEcPP containing mutant ceh1. Biochemical analyses show high phyB protein levels in MEcPP-accumulating plants resulting from reduced expression of phyB antagonists and decreased auxin levels. We show that auxin treatment negatively regulates phyB abundance. Additional studies identify CAMTA3, a MEcPP-activated calcium-dependent transcriptional regulator, as critical for maintaining phyB abundance. These studies provide insights into biological organization fundamentals whereby a signal from a single plastidial metabolite is transduced into an ensemble of regulatory networks controlling the abundance of phyB, positioning plastids at the information apex directing adaptive responses.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fitocromo B/metabolismo , Plastídeos/metabolismo , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Eritritol/análogos & derivados , Eritritol/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Ácidos Indolacéticos/metabolismo , Luz , Fitocromo B/genética , Plastídeos/genética , Transdução de Sinais/efeitos da radiação , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
3.
BMC Plant Biol ; 19(1): 329, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337346

RESUMO

BACKGROUND: Zinc finger proteins (ZFPs) containing only a single zinc finger domain play important roles in the regulation of plant growth and development, as well as in biotic and abiotic stress responses. To date, the evolutionary history and functions of the ZFP gene family have not been identified in cotton. RESULTS: In this paper, we identified 29 ZFP genes in Gossypium hirsutum. This gene family was divided into seven subfamilies, 22 of which were distributed over 17 chromosomes. Bioinformatic analysis revealed that 20 GhZFP genes originated from whole genome duplications and two originated from dispersed duplication events, indicating that whole genome duplication is the main force in the expansion of the GhZFP gene family. Most GhZFP8 subfamily genes, except for GhZFP8-3, were highly expressed during fiber cell growth, and were induced by brassinosteroids in vitro. Furthermore, we found that a large number of GhZFP genes contained gibberellic acid responsive elements, auxin responsive elements, and E-box elements in their promoter regions. Exogenous application of these hormones significantly stimulated the expression of these genes. CONCLUSIONS: Our findings reveal that GhZFP8 genes are involved in cotton fiber development and widely induced by auxin, gibberellin and BR, which provides a foundation for the identification of more downstream genes with potential roles in phytohormone stimuli, and a basis for breeding better cotton varieties in the future.


Assuntos
Gossypium/genética , Reguladores de Crescimento de Planta/fisiologia , Proteínas de Plantas/genética , Dedos de Zinco/genética , Brassinosteroides/metabolismo , Mapeamento Cromossômico , Sequência Conservada/genética , Giberelinas/fisiologia , Gossypium/fisiologia , Ácidos Indolacéticos/metabolismo , Filogenia , Proteínas de Plantas/fisiologia , Reação em Cadeia da Polimerase , Alinhamento de Sequência , Transcriptoma , Dedos de Zinco/fisiologia
4.
World J Microbiol Biotechnol ; 35(6): 90, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147784

RESUMO

The ability of plant growth promoting rhizobacteria (PGPR) for imparting abiotic stress tolerance to plants has been widely explored in recent years; however, the diversity and potential of these microbes have not been maximally exploited. In this study, we characterized four bacterial strains, namely, Pseudomonas aeruginosa PM389, Pseudomonas aeruginosa ZNP1, Bacillus endophyticus J13 and Bacillus tequilensis J12, for potential plant growth promoting (PGP) traits under osmotic-stress, induced by 25% polyethylene glycol (PEG) in the growth medium. Growth curve analysis was performed in LB medium with or without PEG, in order to understand the growth patterns of these bacteria under osmotic-stress. All strains were able to grow and proliferate under osmotic-stress, although their growth rate was slower than that under non-stressed conditions (LB without PEG). Bacterial secretions were analyzed for the presence of exopolysaccharides and phytohormones and it was observed that all four strains released these compounds into the media, both, under stressed and non-stressed conditions. In the Pseudomonas strains, osmotic stress caused a decrease in the levels of auxin (IAA) and cytokinin (tZ), but an increase in the levels of gibberellic acid. The Bacillus strains on the other hand showed a stress-induced increase in the levels of all three phytohormones. P. aeruginosa ZNP1 and B. endophyticus J13 exhibited increased EPS production under osmotic-stress. While osmotic stress caused a decrease in the levels of EPS in P. aeruginosa PM389, B. tequilensis J12 showed no change in EPS quantities released into the media under osmotic stress when compared to non-stressed conditions. Upon inoculating Arabidopsis thaliana seedlings with these strains individually, it was observed that all four strains were able to ameliorate the adverse effects of osmotic-stress (induced by 25% PEG in MS-Agar medium) in the plants, as evidenced by their enhanced fresh weight, dry weight and plant water content, as opposed to osmotic-stressed, non-inoculated plants.


Assuntos
Arabidopsis/microbiologia , Fenômenos Fisiológicos Bacterianos , Secas , Pressão Osmótica , Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/metabolismo , Polissacarídeos Bacterianos/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Bacillus/crescimento & desenvolvimento , Bacillus/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Citocininas/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Rizosfera , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Estresse Fisiológico/fisiologia
5.
BMC Plant Biol ; 19(1): 264, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215396

RESUMO

BACKGROUND: Brassica napus L. has little or no primary dormancy, but exhibits great variation in secondary dormancy. Secondary dormancy potential in oilseed rape can lead to the emergence of volunteer plants that cause genetic contamination, reduced quality and biosafety issues. However, the mechanisms underlying secondary dormancy are poorly understood. In this study, cultivars Huaiyou-WSD-H2 (H) and Huaiyou-SSD-V1 (V), which exhibit low (approximately 5%) and high (approximately 95%) secondary dormancy rate, respectively, were identified. Four samples, before (Hb and Vb) and after (Ha and Va) secondary dormancy induction by polyethylene glycol (PEG), were collected to identify the candidate genes involved in secondary dormancy via comparative transcriptome profile analysis. RESULTS: A total of 998 differentially expressed genes (DEGs), which are mainly involved in secondary metabolism, transcriptional regulation, protein modification and signaling pathways, were then detected. Among these DEGs, the expression levels of those involved in the sulfur-rich indole glucosinolate (GLS)-linked auxin biosynthesis pathway were markedly upregulated in the dormant seeds (Va), which were validated by qRT-PCR and subsequently confirmed via detection of altered concentrations of indole-3-acetic acid (IAA), IAA conjugates and precursors. Furthermore, exogenous IAA applications to cultivar H enhanced secondary dormancy. CONCLUSION: This study first (to our knowledge) elucidated that indole GLS-linked auxin biosynthesis is enhanced during secondary dormancy induced by PEG, which provides valuable information concerning secondary dormancy and expands the current understanding of the role of auxin in rapeseed.


Assuntos
Brassica napus/metabolismo , Ácidos Indolacéticos/metabolismo , Dormência de Plantas , Reguladores de Crescimento de Planta/metabolismo , Brassica napus/genética , Brassica napus/fisiologia , Perfilação da Expressão Gênica , Genes de Plantas/genética , Genes de Plantas/fisiologia , Glucosinolatos/metabolismo , Indóis/metabolismo , Redes e Vias Metabólicas , Dormência de Plantas/genética , Dormência de Plantas/fisiologia , Metabolismo Secundário/genética , Metabolismo Secundário/fisiologia
6.
BMC Plant Biol ; 19(1): 229, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31146692

RESUMO

BACKGROUND: The close planting of dwarfing self-rooted rootstocks is currently a widely used method for apple production; however, self-rooted rootstocks are weak with shallow roots and poor grounding. Therefore, understanding the molecular mechanisms that establish the gravitropic set-point angles (GSAs) of the adventitious roots of self-rooted apple stocks is important for developing self-rooted apple rootstock cultivars with deep roots. RESULTS: We report that the apple FOUR LIPS (MdFLP), an R2R3-MYB transcription factor (TF), functions in establishing the GSA of the adventitious roots of self-rooted apple stocks in response to gravity. Biochemical analyses demonstrate that MdFLP directly binds to the promoters of two auxin efflux carriers, MdPIN3 and MdPIN10, that are involved in auxin transport, activates their transcriptional expression, and thereby promotes the development of adventitious roots in self-rooted apple stocks. Additionally, the apple auxin response factor MdARF19 influences the expression of those auxin efflux carriers and the establishment of the GSA of adventitious roots of apple in response to gravity by directly activating the expression of MdFLP. CONCLUSION: Our findings provide new insights into the transcriptional regulation of MdFLP by the auxin response factor MdARF19 in the regulation of the GSA of adventitious roots of self-rooted apple stocks in response to gravity.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Gravitropismo , Malus/fisiologia , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Transporte Biológico , Ácidos Indolacéticos/metabolismo , Malus/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/fisiologia , Fatores de Transcrição/metabolismo
7.
BMC Plant Biol ; 19(1): 233, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159738

RESUMO

BACKGROUND: Auxin conjugates are hydrolyzed to release free auxin to ensure defined cellular auxin levels or gradients within tissues for proper development or response to environmental signals. The auxin concentration in the abscission zone (AZ) is thought to play an important role in mediating the abscission lag phase. RESULTS: In this study, the full cDNA sequences of seven tomato ILR1-like SlILL genes were identified and characterized, All SlILLs were found to have auxin conjugate hydrolysis activity. The effects of different auxin conjugates on abscission identified IAA-Ile as a candidate to determine the auxin conjugate and auxin conjugate hydrolysis functions in abscission. Treatment of pedicel explants with IAA-Ile for different times showed that application before 6 h could effectively delay abscission. IAA-Ile pre-incubation for 2 h was sufficient to inhibit abscission. These results showed that there is not sufficient auxin conjugates in the AZ to inhibit abscission, and the optimal time to inhibit abscission by the application of exogenous auxin conjugates is before 6 h. Treatment with cycloheximide (CHX, a protein biosynthesis inhibitor) indicated that de novo synthesis of auxin conjugate hydrolases is also required to delay abscission. During abscission, SlILL1, 5, and 6 showed abscission-related gene expression patterns, and SlILL1, 3, 5, 6, and 7 showed increasing expression trends, which collectively might contribute to delay abscission. Silencing the expression of SlILL1, 3, 5, 6, and 7 using virus-induced gene silencing showed that SlILL1, 5, and 6 are major mediators of abscission in tomato. CONCLUSIONS: In the process of abscission, auxin inhibition is concentration dependent, and the concentration of auxin in the AZ was regulated by hydrolyzed auxin conjugates. SlILR1, 5, and 6 play a key role in flower pedicel abscission.


Assuntos
Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Hidrolases/metabolismo , Ácidos Indolacéticos/metabolismo , Lycopersicon esculentum/genética , Inibidores da Síntese de Proteínas/farmacologia , Cicloeximida/farmacologia , Flores/genética , Lycopersicon esculentum/enzimologia
8.
Microbiol Res ; 223-225: 120-128, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178044

RESUMO

Plant growth-promoting bacteria have been highlighted by their potential for application in plant production, allowing the reduction of the use of fertilizers and pesticides, which is due to the ability to stimulate the growth of plants by nitrogen-fixation and production of phytohormones, such as indole-3-acetic acid (IAA). The objective of this study was to verify the potential of plant growth promotion of 25 wild isolates from the Agricultural Microbiology Culture Collection of the Federal University of Lavras (CCMA-UFLA) through the evaluation of the biological nitrogen-fixation capacity and the production of IAA. In addition, the growth of three selected strains inoculated on roots of strawberry seedlings in greenhouse conditions was evaluated. The experiment was conducted in a completely randomized design (CRD), with an 8 × 2 factorial schemes involving eight combinations of bacteria: alone, in pairs and threes, plus the control without inoculation. Two fertilizer levels were used (0% and 50% of nitrogen), totaling 16 treatments with eight replicates each. After 75 days, variables such as root length, root dry weight, aerial part length, aerial part dry weight, leaf number, total dry mass and ultrastructural analysis of the inoculated and uninoculated roots, were evaluated. The results showed that the strawberry crop responded positively to inoculation with the three bacteria combined Azospirillum brasilense (Ab-V5) + Burkholderia cepacia (CCMA 0056) + Enterobacter cloacae (CCMA 1285) compared to the uninoculated controls. More expressive responses in terms of plant growth were observed in relation to the combined inoculation of the three bacterial strains plus fertilizer application with 50% of nitrogen.


Assuntos
Fenômenos Fisiológicos Bacterianos , Fragaria/crescimento & desenvolvimento , Fragaria/microbiologia , Fixação de Nitrogênio , Desenvolvimento Vegetal , Azospirillum brasilense/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biomassa , Burkholderia cepacia/fisiologia , Enterobacter cloacae , Ácidos Indolacéticos/metabolismo , Nitrogênio , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Plântula
9.
Chemosphere ; 232: 439-452, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31158639

RESUMO

This study investigated the role of an allochthonous Gram-positive wastewater bacterium (Bacillus sp. KUJM2) selected through rigorous screening, for the removal of potentially toxic elements (PTEs; As, Cd, Cu, Ni) and promotion of plant growth under PTE-stress conditions. The dried biomass of the bacterial strain removed PTEs (5 mg L-1) from water by 90.17-94.75 and 60.4-81.41%, whereas live cells removed 87.15-91.69 and 57.5-78.8%, respectively, under single-PTE and co-contaminated conditions. When subjected to a single PTE, the bacterial production of indole-3-acetic acid (IAA) reached the maxima with Cu (67.66%) and Ni (64.33%), but Cd showed an inhibitory effect beyond 5 mg L-1 level. The multiple-PTE treatment induced IAA production only up to 5 mg L-1 beyond which inhibition ensued. Enhanced germination rate, germination index and seed production of lentil plant (Lens culinaris) under the bacterial inoculation indicated the plant growth promotion potential of the microbial strain. Lentil plants, as a result of bacterial inoculation, responded with higher shoot length (7.1-27.61%), shoot dry weight (18.22-36.3%) and seed production (19.23-29.17%) under PTE-stress conditions. The PTE uptake in lentil shoots decreased by 67.02-79.85% and 65.94-78.08%, respectively, under single- and multiple-PTE contaminated conditions. Similarly, PTE uptake was reduced in seeds up to 72.82-86.62% and 68.68-85.94%, respectively. The bacteria-mediated inhibition of PTE translocation in lentil plant was confirmed from the translocation factor of the respective PTEs. Thus, the selected bacterium (Bacillus sp. KUJM2) offered considerable potential as a PTE remediating agent, plant growth promoter and regulator of PTE translocation curtailing environmental and human health risks.


Assuntos
Bacillus/crescimento & desenvolvimento , Lens (Planta)/crescimento & desenvolvimento , Poluentes do Solo/análise , Águas Residuárias/microbiologia , Bacillus/metabolismo , Biodegradação Ambiental , Germinação/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Lens (Planta)/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poluentes do Solo/toxicidade
10.
BMC Plant Biol ; 19(1): 197, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088353

RESUMO

BACKGROUND: During maize early kernel development, the dramatic transcriptional reprogramming determines the rate of developmental progression, and phytohormone plays critical role in these important processes. To investigate the phytohormone levels and transcriptome reprogramming profiles during maize early kernel development, two maize inbreds with similar genetic background but different mature kernel sizes (ILa and ILb) were used. RESULTS: The levels of indole-3-acetic acid (IAA) were increased continuously in maize kernels from 5 days after pollination (DAP) to 10 DAP. ILa had smaller mature kernels than ILb, and ILa kernels had significantly lower IAA levels and significantly higher SA levels than ILb at 10 DAP. The different phytohormone profiles correlated with different transcriptional reprogramming in the two kernels. The global transcriptomes in ILa and ILb kernels were strikingly different at 5 DAP, and their differences peaked at 8 DAP. Functional analysis showed that the biggest transcriptome difference between the two kernels is those response to biotic and abiotic stresses. Further analyses indicated that the start of dramatic transcriptional reprogramming and the onset of significantly enriched functional categories, especially the "plant hormone signal transduction" and "starch and sucrose metabolism", was earlier in ILa than in ILb, whereas more significant enrichment of those functional categories occurred at later stage of kernel development in ILb. CONCLUSIONS: These results indicate that later onset of the significantly enriched functional categories, coincide with their stronger activities at a later developmental stage and higher IAA level, are necessary for young kernels to undergo longer mitotic activity and finally develop a larger kernel size. The different onset times and complex interactions of the important functional categories, especially phytohormone signal, and carbohydrate metabolism, form the most important molecular regulators mediating maize early kernel development.


Assuntos
Grão Comestível/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/metabolismo , Transcriptoma , Zea mays/genética , Reprogramação Celular , Grão Comestível/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Zea mays/metabolismo
11.
Plant Physiol Biochem ; 140: 18-26, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31078052

RESUMO

Arabidopsis thaliana cyclic nucleotide-gated ion channel gene 4 (AtCNGC4) loss-of-function mutant dnd2 exhibits elevated accumulation of salicylic acid (SA), dwarfed morphology, reduced hypersensitive response (HR), altered disease resistance and spontaneous lesions on plant leaves. An orthologous barley mutant, nec1, has been reported to over-accumulate indole-3-acetic acid (IAA) and to exhibit changes in stomatal regulation in response to exogenous auxin. Here we show that the Arabidopsis dnd2 over-accumulates both IAA and abscisic acid (ABA) and displays related phenotypic and physiological changes, such as, reduced stomatal size, higher stomatal density and stomatal index. dnd2 showed increased salt tolerance in root growth assay and significantly reduced stomatal conductance, while maintaining near wt reaction in stomatal conductance upon external application of ABA, and probably consequently increased drought stress tolerance. Introduction of both sid2-1 and fmo1 into dnd2 background resulting in removal of SA did not alter stomatal conductance. Hence, the closed stomata of dnd2 is probably a result of increased ABA levels and not increased SA levels. The triple dnd2sid2abi1-1 mutant exhibited intermediate stomatal conductance compared to dnd2 and abi1-1 (ABA insensitive, open stomata), while the response to external ABA was as in abi1-1 suggesting that reduced stomatal conductance in dnd2 is not due to impaired ABA signaling. In conclusion, Arabidopsis dnd2 mutant exhibited ABA overaccumulation and stomatal phenotypes, which may contribute to the observed improvement in drought stress resistance. Thus, Arabidopsis dnd2 mutant may serve as a model for studying crosstalk between biotic and abiotic stress and hormonal response in plants.


Assuntos
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Estômatos de Plantas/metabolismo , Proteínas de Arabidopsis/genética , Secas , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Hordeum/genética , Hordeum/metabolismo , Estômatos de Plantas/genética
12.
Plant Cell Rep ; 38(8): 1013-1016, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31139893

RESUMO

KEY MESSAGE: The hormonal ratios along the barley spike regulate the development, atrophy and abortion of the spikelets and could be the mechanism by which the barley spike adapts its yield potential. Barley (Hordeum vulgare L.) is one of the oldest cereal crops known to be cultivated since about 10,000 years. The inflorescence of cultivated barley is an indeterminate spike that produces three single-flowered spikelets at each rachis node which make it unique among the grasses. The yield production in barley is predominantly controlled by very important parameters such as number of tillers and number of spikelets per spike. These two parameters are negatively correlated. Therefore, studying the biological and genetics of the spikelet development during the spike developmental stages is essential for breeding programs. Here we summarize our current understanding of the crosstalk between hormones such as auxin, cytokinin, gibberellin and abscisic acid along the spike and what is their role in regulating spike and spikelet development in barley. We conclude that the hormonal ratios at the apical, central, and basal sections of the spike not only regulate the spike developmental stages, but also the development, atrophy, and abortion of the spikelets. This hormonal dependent modification of the grain number along the spike could be the mechanism by which the barley spike adapts its yield potential.


Assuntos
Hordeum/metabolismo , Hordeum/fisiologia , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/genética
13.
Plant Cell Physiol ; 60(7): 1581-1594, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31058993

RESUMO

Lateral root (LR) formation and development play a vital role in plant development by permitting the establishment of branched root systems. It is well known that nutrient availability controls LR development. Moreover, LR development is fine-tuned by a myriad of hormonal signals. Many transcription factors (TFs) participate in LR development. Here, we discuss the TFs involved in the nitrate and auxin signaling pathways and how these function in the regulation of LR formation and development in chrysanthemum. AtTCP20 is a plant-specific TF, which can modulate LR development in response to nitrate. The roles of CmTCP20 in LR development were identified by overexpression in chrysanthemum and heterologous expression in Arabidopsis. Overexpression of CmTCP20 significantly increased the number and average length of LRs compared with the wild type in chrysanthemum and Arabidopsis. We also found that CmTCP20 positively influenced auxin accumulation in the LRs at least partly by improving auxin biosynthesis, transport and response, thereby promoting LR development. Moreover, we found that CmTCP20 interacts with an auxin response factor, CmARF8, which also can be induced by nitrate and combined to proximal sites in the upstream promoter region of CmCYCB1;1 to positively regulate the cell cycle. The CmTCP20-CmARF8 heterodimer links nitrate and auxin signaling and converts cell-cycle signals to regulate LR initiation and growth.


Assuntos
Chrysanthemum/crescimento & desenvolvimento , Ácidos Indolacéticos/metabolismo , Nitratos/metabolismo , Proteínas de Plantas/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Fatores de Transcrição/fisiologia , Arabidopsis , Chrysanthemum/metabolismo , Chrysanthemum/fisiologia , Reguladores de Crescimento de Planta/metabolismo , Reguladores de Crescimento de Planta/fisiologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Plantas Geneticamente Modificadas , Transdução de Sinais , Fatores de Transcrição/metabolismo
14.
Plant Sci ; 283: 177-188, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128687

RESUMO

Phytohormone signaling is involved in the low-phosphate (LP) response and causes root system changes. To understand the roles of auxin and gibberellic acid (GA) in the maize response to LP stress, inbred line Q319 was used to identify the changes in root morphology and the gene expression response to LP stress with or without exogenous auxin, GA or their inhibitors. The root morphology, IAA and GAs concentration and genes related to the LP response, cell elongation and division, auxin transport and signaling, and GA synthesis and signaling were analyzed. The LP-induced maize root morphological adaption was dependent on changes in the expression of related genes, like IPS1, pht1;1 LPR1b, KRPs, and EXPB1-4. The altered local auxin concentration and signaling were involved in promoting axial root elongation and reducing lateral root density and length under LP conditions, which were regulated by PID and PP2A activity and the auxin signaling pathway. The upregulation of the GA synthesis genes AN1, GA20ox1, and GA20ox2 and the downregulation of the GA inactive genes GA2ox1 and GA2ox2 were observed in maize roots subjected to LP stress, and the increased GA biosynthesis and signaling were involved in root growth. Both hormones participate in LP stress response and jointly regulated root modification and LP acclimation in maize.


Assuntos
Giberelinas/fisiologia , Ácidos Indolacéticos/metabolismo , Fosfatos/deficiência , Reguladores de Crescimento de Planta/fisiologia , Zea mays/metabolismo , Regulação da Expressão Gênica de Plantas , Giberelinas/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Estresse Fisiológico , Zea mays/anatomia & histologia , Zea mays/fisiologia
15.
Plant Sci ; 283: 266-277, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128697

RESUMO

Hormones play an important role in fruit ripening and in response to biotic stress. Nevertheless, analyses of hormonal profiling during plant development and defense are scarce. In this work, changes in hormonal metabolism in grapevine (Vitis vinifera) were compared between a susceptible (Trincadeira) and a tolerant (Syrah) variety during grape ripening and upon infection with Botrytis cinerea. Infection of grapes with the necrotrophic pathogen Botrytis cinerea leads to significant economic losses worldwide. Peppercorn-sized fruits were infected in the field and mock-treated and infected berries were collected at green, veraison and harvest stages for hormone analysis and targeted qPCR analysis of genes involved in hormonal metabolism and signaling. Results indicate a substantial reprogramming of hormonal metabolism during grape ripening and in response to fungal attack. Syrah and Trincadeira presented differences in the metabolism of abscisic acid (ABA), indole-3-acetic acid (IAA) and jasmonates during grape ripening that may be connected to fruit quality. On the other hand, high basal levels of salicylic acid (SA), jasmonates and IAA at an early stage of ripening, together with activated SA, jasmonates and IAA signaling, likely enable a fast defense response leading to grape resistance/ tolerance towards B. cinerea. The balance among the different phytohormones seems to depend on the ripening stage and on the intra-specific genetic background and may be fundamental in providing resistance or susceptibility. In addition, this study indicated the involvement of SA and IAA in defense against necrotrophic pathogens and gains insights into possible strategies for conventional breeding and/or gene editing aiming at improving grape quality and grape resistance against Botrytis cinerea.


Assuntos
Ácido Abscísico/metabolismo , Botrytis/metabolismo , Ciclopentanos/metabolismo , Ácidos Indolacéticos/metabolismo , Oxilipinas/metabolismo , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/metabolismo , Ácido Salicílico/metabolismo , Vitis/metabolismo , Ácido Abscísico/fisiologia , Antocianinas/metabolismo , Reguladores de Crescimento de Planta/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Especificidade da Espécie , Vitis/crescimento & desenvolvimento , Vitis/microbiologia
16.
Plant Cell Rep ; 38(8): 951-963, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31062133

RESUMO

KEY MESSAGE: Overexpression of SlMBP9 reduced auxin biosynthesis and transport, and negatively regulated lateral root formation and apical dominance. MADS-box transcription factors play a critical role in plant development. In this study, we describe SlMBP9, a novel MADS-box gene that is expressed in the roots of tomato plants. Tomato lines that over- or under-expressed SlMBP9 were generated using a transgenic approach. The number of lateral roots (LRs) were reduced in SlMBP9-overexpressing lines but slightly increased in SlMBP9-silenced lines. A physiological index revealed that the auxin content significantly decreased in the root maturation zone of the overexpression lines. In addition, gene expression analysis revealed that the expression of the polar auxin transporter genes PIN1 and ABCB19/MDR1 and genes involved in auxin biosynthesis was downregulated in the stems of overexpression lines, which is consistent with the reduced accumulation of auxin in the root maturation zone. Exogenous indole-3-acetic acid (auximone) rescued the lateral root phenotypes of the SlMBP9-overexpressing lines. Overexpression of SlMBP9 resulted in dwarf plants, enhanced lateral buds and reduced the gibberellin content in the stems. Together, these results suggest that SlMBP9 plays a negative role in the process of auxin biosynthesis and transport.


Assuntos
Ácidos Indolacéticos/metabolismo , Lycopersicon esculentum/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Transporte Biológico/genética , Transporte Biológico/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Lycopersicon esculentum/genética , Proteínas de Plantas/genética , Raízes de Plantas/genética
17.
J Microbiol Biotechnol ; 29(7): 1096-1103, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31091866

RESUMO

UCB-1 is the commercial rootstock of pistachio. Reproduction of this rootstock by tissue culture is limited by low levels of proliferation rate. Therefore, any compound that improves the proliferation rate and the quality of the shoots can be used in the process of commercial reproduction of this rootstock. Use of plant growth-promoting bacteria is one of the best ideas. Given the beneficial effects of nanoparticles in enhancement of the growth in plant tissue cultures, the aim of the present study was to investigate the effects of nanoencapsulation of plant growth-promoting rhizobacteria (using silica nanoparticles and carbon nanotubes) and their metabolites in improving UCB1 pistachio micropropagation. The experiment was conducted in a completely randomized design with three replications. Before planting, treatments on the DKW medium were added. The results showed that the use of Pseudomonas fluorescens VUPF5 and Bacillus subtilis VRU1 nanocapsules significantly enhanced the root length and proliferation. The nanoformulation of the VUPF5 metabolite led to the highest root length (6.26 cm) and the largest shoot (3.34 cm). Inoculation of explants with the formulation of the metabolites (both bacterial strains) significantly elevated the average shoot length and the fresh weight of plant compared to the control. The explants were dried completely using both bacterial strains directly and with capsule coating after the three days.


Assuntos
Alginatos/química , Nanopartículas/química , Nanotubos de Carbono/química , Pistacia , Reguladores de Crescimento de Planta/química , Raízes de Plantas/crescimento & desenvolvimento , Dióxido de Silício/química , Bacillus subtilis/química , Bacillus subtilis/metabolismo , Ácidos Indolacéticos/química , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacologia , Reguladores de Crescimento de Planta/metabolismo , Reguladores de Crescimento de Planta/farmacologia , Raízes de Plantas/efeitos dos fármacos , Pseudomonas fluorescens/química , Pseudomonas fluorescens/metabolismo , Microbiologia do Solo
18.
Science ; 364(6435): 57-62, 2019 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-30948546

RESUMO

Rho guanosine triphosphatases (GTPases) are master regulators of cell signaling, but how they are regulated depending on the cellular context is unclear. We found that the phospholipid phosphatidylserine acts as a developmentally controlled lipid rheostat that tunes Rho GTPase signaling in Arabidopsis Live superresolution single-molecule imaging revealed that the protein Rho of Plants 6 (ROP6) is stabilized by phosphatidylserine into plasma membrane nanodomains, which are required for auxin signaling. Our experiments also revealed that the plasma membrane phosphatidylserine content varies during plant root development and that the level of phosphatidylserine modulates the quantity of ROP6 nanoclusters induced by auxin and hence downstream signaling, including regulation of endocytosis and gravitropism. Our work shows that variations in phosphatidylserine levels are a physiological process that may be leveraged to regulate small GTPase signaling during development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Fosfatidilserinas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Membrana Celular/química , Membrana Celular/metabolismo , Endocitose/genética , Regulação da Expressão Gênica de Plantas , Gravitropismo/genética , Ácidos Indolacéticos/metabolismo , Proteínas Monoméricas de Ligação ao GTP/genética , Fosfatidilserinas/farmacologia , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Transdução de Sinais , Imagem Individual de Molécula
19.
J Basic Microbiol ; 59(6): 579-590, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30980735

RESUMO

Excessive cadmium (Cd) accumulation in soil can adversely affect plants, animals, microbes, and humans; therefore, novel and uncharacterized Cd-resistant plant-growth-promoting rhizobacteria (PGPR) are required to address this issue. In the paper, 13 bacteria were screened, their partial 16S rRNA sequences determined, and the isolates, respectively, clustered into Curtobacterium (7), Chryseobacterium (4), Cupriavidus (1), and Sphingomonas (1). Evaluation of PGP traits, including indole-3-acetic acid (IAA) production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, siderophore secretion, and cyanhydric acid production, identified Cupriavidus necator GX_5, Sphingomonas sp. GX_15, and Curtobacterium sp. GX_31 as promising candidates for PGPR based on high IAA or ACC deaminase production. Additionally, root-elongation assays indicated that inoculating GX_5, _15, or _31 increased Brassica napus root length both in the presence and absence of Cd by 19.75-29.96% and 19.15-31.69%, respectively. Pot experiments indicated that inoculating B. napus with GX_5, _15, and _31 significantly increased the dry weight of above-ground tissues and root biomass by 40.97-85.55% and 18.99-103.13%, respectively. Moreover, these isolates significantly increased Cd uptake in the aerial parts and root tissue of B. napus by 7.38-11.98% and 48.09-79.73%, respectively. These results identified GX_5, _15, or _31 as excellent promoters of metal remediation by using microorganism-associated phytoremediation.


Assuntos
Bactérias/metabolismo , Brassica napus/microbiologia , Brassica napus/fisiologia , Cádmio/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Poluentes do Solo/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Biomassa , Brassica napus/crescimento & desenvolvimento , Brassica napus/metabolismo , Carbono-Carbono Liases/metabolismo , DNA Bacteriano/genética , Ácidos Indolacéticos/metabolismo , Filogenia , Reguladores de Crescimento de Planta/classificação , Reguladores de Crescimento de Planta/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Sideróforos/metabolismo , Solo/química , Microbiologia do Solo
20.
Plant Physiol Biochem ; 139: 738-745, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31010613

RESUMO

Weisiensin B, a new ent-kaurene diterpenoid isolated from Isodon weisiensis (C. Y. Wu) H. Hara, exhibited phytotoxic effects on root growth and lateral root development in Arabidopsis thaliana seedlings. Primary root growth and lateral root formation in A. thaliana seedlings were significantly inhibited by 10-20 µM weisiensin B. Additionally, the role of weisiensin B in response to polar auxin transport in A. thaliana roots was investigated using a PIN promoter (PIN::GUS), a green fluorescent protein (GFP) fusion protein reporter (PINs::PINs:GFP), and DR5::GUS and DR5::GFP reporter genes. The results indicated that weisiensin B reduced the expression of PIN2, PIN3, PIN4, PIN7, and AUX1 genes and significantly decreased the abundance of PIN2-GFP, PIN3-GFP, PIN4-GFP, PIN7-GFP, and AUX1-GFP fusion proteins at their respective cellular locations, simultaneously causing auxin accumulation in the root apex. These results suggest that weisiensin B interferes with polar auxin transport in A. thaliana roots, resulting in auxin accumulation in the root meristematic cells and the inhibition of root growth and lateral root development.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Transporte Biológico/efeitos dos fármacos , Diterpenos/farmacologia , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos
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