scholarly journals Uniform distribution of 35S promoter-driven mDII auxin control sensor in leaf primordia

2018 ◽  
Author(s):  
Chunmei Guan ◽  
Fei Du ◽  
Yuling Jiao

AbstractThe DII sensor has been an invaluable tool to map spatiotemporal auxin response and distribution in the model plant Arabidopsis thaliana. The DII sensor and mDII control sensor are driven by the widely used constitutive 35S promoter. However, the reliability of DII sensor has recently been questioned (Bhatia and Heisler, 2018). Here we provide additional evidence to show that the mDII control sensor is indeed uniformly distributed in early leaf primordia, which echoes the original reports (Vernoux et al., 2011; Brunoud et al., 2012). We also use DII/mDII and the PRS5A promoter-driven R2D2 sensors to confirm asymmetric auxin signaling in early leaf primordia. On the other hand, we provide evidence that light penetration may lead to artifacts during whole-mount imaging.

2019 ◽  
Author(s):  
Parinita Majumdar ◽  
Premananda Karidas ◽  
Imran Siddiqi ◽  
Utpal Nath

ABSTRACTAuxin response is regulated by a group of AUX/IAA transcriptional inhibitors that suppress auxin signaling in the absence of the hormone. While the degradation of these proteins upon auxin signaling has been well studied, the molecular control of their rapid turn-over is not clearly understood. Here, we report that the TARANI/ UBIQUITIN PROTEASE 14 protein in Arabidopsis thaliana (Arabidopsis) is required for AUX/IAA degradation. The tni mutation was originally identified in a forward genetic screen to isolate mutants with altered leaf shape. Detailed phenotypic analysis revealed that tni displays pleiotropic phenotypic alterations that resemble auxin-related defects. The activity of auxin responsive reporters DR5::GUS, DR5::nYFP and IAA2::GUS was reduced in tni organs, implying that TNI is required for normal auxin response. Genetic interaction studies suggested that TNI acts along with TIR1, ARF7, AUX1 and PIN1 – molecules involved in auxin signaling or transport. A map-based cloning approach combined with next-generation sequencing identified TNI as UBIQUITIN SPECIFIC PROTEASE14 which is involved in ubiquitin recycling. In tni, the mutant primary transcript is spliced inefficiently, which is predicted to produce an aberrant protein product in addition to the normal protein, where a polypeptide corresponding to the 3rd intron in inserted in-frame within the Zn-finger domain of UBP14. The tni plants accumulated poly-ubiquitin chains and excess poly-ubiquitinated proteins due to reduced TNI activity. Improper ubiquitin recycling affected the degradation of DII:VENUS, IAA18:GUS and HS::AXR3-NT:GUS, resulting in their stabilization in the tni mutant. Thus, our study identified a function for TNI/UBP14 in regulating auxin response through ubiquitin recycling.


2019 ◽  
Author(s):  
Feng Zhang ◽  
Wenqing Tao ◽  
Ruiqi Sun ◽  
Junxia Wang ◽  
Cuiling Li ◽  
...  

AbstractThe development of lateral roots in Arabidopsis thaliana is strongly dependent on signaling directed by the AUXIN RESPONSE FACTOR7 (ARF7), which in turn activates LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factors (LBD16, 18, 29 and 33). Here, the product of PRH1, a PR-1 homolog annotated previously as encoding a pathogen-responsive protein, was identified as a target of ARF7-mediated auxin signaling and also as participating in the development of lateral roots. PRH1 was shown to be strongly induced by auxin treatment, and plants lacking a functional copy of PRH1 formed fewer lateral roots. The transcription of PRH1 was controlled by the binding of both ARF7 and LBDs to its promoter region. An interaction was detected between PRH1 and GATA23, a protein which regulates cell identity in lateral root founder cells.Author SummaryIn Arabidopsis thaliana AUXIN RESPONSE FACTOR7 (ARF7)-mediated auxin signaling plays a key role in lateral roots (LRs) development. The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factors (LBD16, 18, 29 and 33) act downstream of ARF7-mediated auxin signaling to control LRs formation. Here, the PR-1 homolog PRH1 was identified as a novel target of both ARF7 and LBDs (especially the LBD29) during auxin induced LRs formation, as both ARF7 and LBDs were able to bind to the PRH1 promoter. More interestingly, PRH1 has a physical interaction with GATA23, which has been also reported to be up-regulated by auxin and influences LR formation through its regulation of LR founder cell identity. Whether the interaction between GATA23 and PRH1 affects the stability and/or the activity of either (or both) of these proteins remains an issue to be explored. This study provides improves new insights about how auxin regulates lateral root development.


2021 ◽  
Vol 22 (11) ◽  
pp. 5739
Author(s):  
Joo Yeol Kim ◽  
Hyo-Jun Lee ◽  
Jin A Kim ◽  
Mi-Jeong Jeong

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.


2021 ◽  
Vol 22 (1) ◽  
pp. 437
Author(s):  
Meng Wang ◽  
Panpan Li ◽  
Yao Ma ◽  
Xiang Nie ◽  
Markus Grebe ◽  
...  

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (β-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.


2022 ◽  
Vol 23 (1) ◽  
pp. 510
Author(s):  
Pan Luo ◽  
Dongwei Di ◽  
Lei Wu ◽  
Jiangwei Yang ◽  
Yufang Lu ◽  
...  

Auxin, primarily indole-3-acetic acid (IAA), is a versatile signal molecule that regulates many aspects of plant growth, development, and stress response. Recently, microRNAs (miRNAs), a type of short non-coding RNA, have emerged as master regulators of the auxin response pathways by affecting auxin homeostasis and perception in plants. The combination of these miRNAs and the autoregulation of the auxin signaling pathways, as well as the interaction with other hormones, creates a regulatory network that controls the level of auxin perception and signal transduction to maintain signaling homeostasis. In this review, we will detail the miRNAs involved in auxin signaling to illustrate its in planta complex regulation.


2020 ◽  
Author(s):  
Sharma Nidhi ◽  
Liu Tie

AbstractIn Arabidopsis, the genes SHOOT MERISTEMLESS (STM) and CLAVATA3 (CLV3) antagonistically regulate shoot meristem development. STM is essential for both development and maintenance of the meristem, as stm mutants fail to develop a shoot meristem during embryogenesis. CLV3, on the other hand, negatively regulates meristem proliferation, and clv3 mutants possess an enlarged shoot meristem. Genetic interaction studies revealed that stm and clv3 dominantly suppress each other’s phenotypes. STM works in conjunction with its closely related homologue KNOTTED1-LIKE HOMEOBOX GENE 6 (KNAT6) to promote meristem development and organ separation, as stm knat6 double mutants fail to form a meristem and produce a fused cotyledon. In this study, we show that clv3 fails to promote post-embryonic meristem formation in stm-1 background if we also remove KNAT6. stm-1 knat6 clv3 triple mutants result in early meristem termination and produce fused cotyledons similar to stm knat6 double mutant. Notably, the stm-1 knat6 and stm-1 knat6 clv3 alleles lack tissue in the presumed region of SAM. stm knat6 clv3 also showed reduced inflorescence size and shoot apex size as compared to clv3 single or stm clv3 double mutants. In contrast to previously published data, these data suggest that stm is epistatic to clv3 in postembryonic meristem development.HighlightSTM and KNAT6 genes determine post-embryonic meristem formation and activity in Arabidopsis. clv3 mutation is unable to rescue the stm knat6 meristemless phenotype.


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Luigi Bregant ◽  
Lucia Parussini ◽  
Valentino Pediroda

In order to perform the accurate tuning of a machine and improve its performance to the requested tasks, the knowledge of the reciprocal influence among the system's parameters is of paramount importance to achieve the sought result with minimum effort and time. Numerical simulations are an invaluable tool to carry out the system optimization, but modeling limitations restrict the capabilities of this approach. On the other side, real tests and measurements are lengthy, expensive, and not always feasible. This is the reason why a mixed approach is presented in this work. The combination, through recursive cokriging, of low-fidelity, yet extensive, numerical model results, together with a limited number of highly accurate experimental measurements, allows to understand the dynamics of the machine in an extended and accurate way. The results of a controllable experiment are presented and the advantages and drawbacks of the proposed approach are also discussed.


1993 ◽  
Vol 30 (03) ◽  
pp. 627-638
Author(s):  
M. T. Dixon

An arbitrary number of competitors are presented with independent Poisson streams of offers consisting of independent and identically distributed random variables having the uniform distribution on [0, 1]. The players each wish to accept a single offer before a known time limit is reached and each aim to maximize the expected value of their offer. Rejected offers may not be recalled, but they are passed on to the other players according to a known transition matrix. This paper finds equilibrium points for two such games, and demonstrates a two-player game with an equilibrium point under which the player with the faster stream of offers has a lower expected reward than his opponent.


2017 ◽  
Vol 69 (2) ◽  
pp. 329-339 ◽  
Author(s):  
Pavel Cherenkov ◽  
Daria Novikova ◽  
Nadya Omelyanchuk ◽  
Victor Levitsky ◽  
Ivo Grosse ◽  
...  

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