Momilactone B inhibits Arabidopsis growth and development via disruption of ABA and auxin signaling

AbstractIn competition for limited resources, many plants release allelochemicals to inhibit the growth of neighboring plants. Momilactone B (MB) is a major allelochemical produced by rice (Oryza sativa), however its mode of action is currently unknown. We used Arabidopsis (Arabidopsis thaliana) as a model system to evaluate potential mechanisms underlying the inhibitory effects of MB on seed germination, seedling establishment and root growth through the use of confocal microscopy and the examination of transcriptional responses in MB-treated seedlings. In response to MB treatment, transcript levels for genes encoding several key ABA biosynthetic enzymes and signaling components, including the transcription factor ABA-INSENSITIVE 4 (ABI4), were dramatically increased. Additionally, ABA insensitive 4 (abi4) mutant seedlings exhibited reduced susceptibility to exogenously-provided MB. Although the transcript levels of DELLA genes, which negatively regulate GA signaling, were significantly increased upon MB exposure, exogenous GA application did not reverse the inhibitory effects of MB on Arabidopsis germination and seedling development. Moreover, a reduction in seedling root meristematic activity, associated with reduced expression of auxin biosynthetic genes and efflux transporters, and apparent lowered auxin content, was observed in MB-treated root tips. Exogenous auxin applications partially rescued the inhibitory effects of MB observed in root growth. Our results indicate that MB suppresses Arabidopsis seed germination and root growth primarily via disruption of ABA and auxin signaling. These findings underscore the crucial roles played by phytohormones in mediating responses to allelochemical exposure.One-sentence summaryMomilactone B, the key allelochemical of rice, inhibits Arabidopsis growth and development via disruption of ABA and auxin signaling, suggesting the crucial roles of phytohormones in plant allelopathy

Download Full-text

RNA-Seq Transcriptome Analysis of Rice Primary Roots Reveals the Role of Flavonoids in Regulating the Rice Primary Root Growth

Genes ◽

10.3390/genes10030213 ◽

2019 ◽

Vol 10 (3) ◽

pp. 213

Author(s):

Yu Xu ◽

Junjie Zou ◽

Hongyan Zheng ◽

Miaoyun Xu ◽

Xuefeng Zong ◽

...

Keyword(s):

Cell Wall ◽

Root Growth ◽

Primary Root ◽

Glutathione Metabolism ◽

Auxin Signaling ◽

Antioxidant Enzyme Activities ◽

Rna Seq ◽

Root Tips ◽

Primary Roots ◽

Quercetin Treatment

Flavonoids play important roles in root development and in its tropic responses, whereas the flavonoids-mediated changes of the global transcription levels during root growth remain unclear. Here, the global transcription changes in quercetin-treated rice primary roots were analyzed. Quercetin treatment significantly induced the inhibition of root growth and the reduction of H2O2 and O2− levels. In addition, the RNA-seq analysis revealed that there are 1243 differentially expressed genes (DEGs) identified in quercetin-treated roots, including 1032 up-regulated and 211 down-regulated genes. A gene ontology (GO) enrichment analysis showed that the enriched GO terms are mainly associated with the cell wall organization, response to oxidative stress, and response to hormone stimulus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis showed that the enriched DEGs are involved in phenylpropanoid biosynthesis, glutathione metabolism, and plant hormone signal transduction. Moreover, the quercetin treatment led to an increase of the antioxidant enzyme activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in rice roots. Also, the quercetin treatment altered the DR5:GUS expression pattern in the root tips. All of these data indicated that the flavonoids-mediated transcription changes of genes are related to the genes involved in cell wall remodeling, redox homeostasis, and auxin signaling, leading to a reduced cell division in the meristem zone and cell elongation in the elongation zone of roots.

Download Full-text

Static magnetic field regulates Arabidopsis root growth via auxin signaling

Scientific Reports ◽

10.1038/s41598-019-50970-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Yue Jin ◽

Wei Guo ◽

Xupeng Hu ◽

Mengmeng Liu ◽

Xiang Xu ◽

...

Keyword(s):

Magnetic Field ◽

Root Growth ◽

Static Magnetic Field ◽

Molecular Mechanisms ◽

Biological Significance ◽

Auxin Signaling ◽

Biological Processes ◽

Root Tips ◽

The North ◽

Living Organisms

Abstract Static magnetic field (SMF) plays important roles in biological processes of many living organisms. In plants, however, biological significance of SMF and molecular mechanisms underlying SMF action remain largely unknown. To address these questions, we treated Arabidopsis young seedlings with different SMF intensities and directions. Magnetic direction from the north to south pole was adjusted in parallel (N0) with, opposite (N180) and perpendicular to the gravity vector. We discovered that root growth is significantly inhanced by 600 mT treatments except for N180, but not by any 300 mT treatments. N0 treatments lead to more active cell division of the meristem, and higher auxin content that is regulated by coordinated expression of PIN3 and AUX1 in root tips. Consistently, N0-promoted root growth disappears in pin3 and aux1 mutants. Transcriptomic and gene ontology analyses revealed that in roots 85% of the total genes significantly down-regulated by N0 compared to untreatment are enriched in plastid biological processes, such as metabolism and chloroplast development. Lastly, no difference in root length is observed between N0-treated and untreated roots of the double cryptochrome mutant cry1 cry2. Taken together, our data suggest that SMF-regulated root growth is mediated by CRY and auxin signaling pathways in Arabidopsis.

Download Full-text

Influence of graphene on the multiple metabolic pathways of Zea mays roots based on transcriptome analysis

PLoS ONE ◽

10.1371/journal.pone.0244856 ◽

2021 ◽

Vol 16 (1) ◽

pp. e0244856

Author(s):

Zhiwen Chen ◽

Jianguo Zhao ◽

Jie Song ◽

Shenghua Han ◽

Yaqin Du ◽

...

Keyword(s):

Zea Mays ◽

Root Growth ◽

Growth And Development ◽

Plant Root ◽

Control Group ◽

Molecular Response ◽

Root Tips ◽

Positive Effects ◽

Maize Seeds ◽

Maize Roots

Graphene reportedly exerts positive effects on plant root growth and development, although the corresponding molecular response mechanism remains to be elucidated. Maize seeds were randomly divided into a control and experimental group, and the roots of Zea mays L. seedlings were watered with different concentrations (0–100 mg/L) of graphene to explore the effects and molecular mechanism of graphene on the growth and development of Z. mays L. Upon evaluating root growth indices, 50 mg/L graphene remarkably increased total root length, root volume, and the number of root tips and forks of maize seedlings compared to those of the control group. We observed that the contents of nitrogen and potassium in rhizosphere soil increased following the 50 mg/L graphene treatment. Thereafter, we compared the transcriptome changes in Z. mays roots in response to the 50 mg/L graphene treatment. Transcriptional factor regulation, plant hormone signal transduction, nitrogen and potassium metabolism, as well as secondary metabolism in maize roots subjected to graphene treatment, exhibited significantly upregulated expression, all of which could be related to mechanisms underlying the response to graphene. Based on qPCR validations, we proposed several candidate genes that might have been affected with the graphene treatment of maize roots. The transcriptional profiles presented here provide a foundation for deciphering the mechanism underlying graphene and maize root interaction.

Download Full-text

Assessment Of Biologically Synthesized Ag Nanoparticles Toxicity Against E. coli, Staphylococcus aureus, Parachlorella kessleri And Sinapis alba

Nova Biotechnologica et Chimica ◽

10.1515/nbec-2015-0016 ◽

2015 ◽

Vol 14 (1) ◽

pp. 69-77 ◽

Cited By ~ 3

Author(s):

Jana Kaduková ◽

Oksana Velgosová ◽

Anna Mražíková ◽

Renáta Marcinčáková ◽

Eva Tkáčová

Keyword(s):

Staphylococcus Aureus ◽

Silver Nanoparticles ◽

Seed Germination ◽

Root Growth ◽

Sinapis Alba ◽

Bacterial Cells ◽

Inhibitory Effects ◽

Plant Seed ◽

E Coli ◽

Parachlorella Kessleri

Abstract In general, Ag+ ions and AgNPs are considered to be the most toxic for bacterial cells and less toxic for higher organisms. In the present work inhibitory effects of biologically prepared silver nanoparticles on the growth of bacteria E. coli CCM 3954 and Staphylococcus aureus CCM 3953, green microscopic alga Parachlorella kessleri LARG/1 and seed germination and root growth of plant Sinapis alba seeds were investigated. Surprisingly, silver nanoparticles showed much stronger inhibitory effects on plant seed germination and root growth than on the bacterial growth. At concentration of 75 mg/l AgNPs both seed germination and root growth of Sinapis alba was inhibited whereas inhibition of the growth of E. coli and S. aureus was observed at >195 mg/l. Growth inhibition of alga Parachlorella kessleri was recorded at 300 mg/l AgNPs concentration. The inhibitory effect of silver ions was much higher compared to silver nanoparticles. Even 20 mg/l concentration of Ag+ ions inhibited the root growth and concentration > 45 mg/l inhibited germination of Sinapis alba seeds. Inhibition zones in both studied bacteria were found at concentration > 140 mg/l.

Download Full-text

A Foldable Chip Array for the Continuous Investigation of Seed Germination and the Subsequent Root Development of Seedlings

Micromachines ◽

10.3390/mi10120884 ◽

2019 ◽

Vol 10 (12) ◽

pp. 884

Author(s):

Zhao Xi Song ◽

Hui Hui Chai ◽

Feng Chen ◽

Ling Yu ◽

Can Fang

Keyword(s):

Seed Germination ◽

Root Growth ◽

Plant Development ◽

Root Development ◽

Single Channel ◽

Root Hairs ◽

Seedling Development ◽

Root Tips ◽

Observation Window ◽

The Individual

Seed germination and seedling root development are important indicators of plant development. This work designed and fabricated a foldable microfluidic chip array for conducting nondestructive and continuous evaluation of seed germination and subsequent seedling development in situ. Each plant chamber has two functional units: seed germination part and root-growth part. The root-growth parts are themselves connected to a single channel designed to provide a uniform culture medium for plant growth. The individual chips are connected into an array using elastic hinges that facilitate the folding and unfolding of the array to accommodate different viewing purposes. In the folded state, the seed germination chambers form a closely spaced array platform to facilitate the comparison of seed germination and plant development characteristics. Unfolding the array facilitates a clear examination of root development within the root-growth parts. The observation window of an individual chip facilitates either the direct examination of the developing seedling (e.g., stems and leaves) or the use of a microscope for examining microscale features (e.g., root tips and root hairs). The potential of the proposed foldable chip array as a new cultivation platform for botanic studies is demonstrated by examining the seed germination and seedling development of tobacco (Nicotiana tabacum) under different cultivation conditions.

Download Full-text

The AFB1 auxin receptor controls rapid auxin signaling and root growth through membrane depolarization in Arabidopsis thaliana

10.1101/2021.01.05.425399 ◽

2021 ◽

Author(s):

Nelson BC Serre ◽

Dominik Kralík ◽

Ping Yun ◽

Sergey Shabala ◽

Zdeněk Slouka ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Growth Inhibition ◽

Cell Types ◽

Membrane Depolarization ◽

Root Growth Inhibition ◽

Auxin Signaling ◽

Auxin Receptor ◽

Transcriptional Responses

AbstractThe existence of an electric gradient across membranes is essential for a cell operation. In plants, application of the growth regulator auxin (IAA) causes almost instantaneous membrane depolarization in various cell types, making membrane depolarization a hallmark of the rapid non-transcriptional responses to IAA. Auxin triggers rapid root growth inhibition; a process that underlies gravitropic bending. The growth and depolarization responses to auxin show remarkable similarities in dynamics, requirement of auxin influx and the involvement of the TIR1/AFB auxin coreceptors, but whether auxin-induced depolarization participates in root growth inhibition remains unanswered. Here, we established a toolbox to dynamically visualize membrane potential in vivo in Arabidopsis thaliana roots by combining the DISBAC2(3) fluorescent probe with microfluidics and vertical stage microscopy. This way we show that auxin-induced membrane depolarization tightly correlates with rapid root growth inhibition and that the cells of the transition zone/early elongation zone are the most responsive to auxin. Further, we demonstrate that auxin cycling in and out of the cells through AUX1 influx and PIN2 efflux is not essential for membrane depolarization and rapid root growth inhibition but acts as a facilitator of these responses. The rapid membrane depolarization by auxin instead strictly depends on the AFB1 auxin receptor, while the other TIR1/AFB paralogues contribute to this response. The lack of membrane depolarization in the afb1 mutant explains the lack of the immediate root growth inhibition. Finally, we show that AFB1 is required for the rapid depolarization and rapid growth inhibition of cells at the lower side of the gravistimulated root. These results are instrumental in understanding the physiological significance of membrane depolarization for the gravitropic response of the root and clarify the role of AFB1 as the receptor central for rapid auxin responses, adding another piece to the puzzle in understanding the biology of the phytohormone auxin.

Download Full-text