scholarly journals Shade-induced WRKY transcription factors restrict root growth during the shade avoidance response

2021 ◽  
Author(s):  
Daniele Rosado ◽  
Amanda Ackermann ◽  
Olya Spassibojko ◽  
Magdalena Rossi ◽  
Ullas V Pedmale
Keyword(s):  
Transcription Factors ◽  
Root Growth ◽  
Avoidance Response ◽  
Primary Root ◽  
Hypocotyl Elongation ◽  
Shade Avoidance ◽  
Wrky Transcription Factors ◽  
Tomato Seedlings ◽  
Induced Genes ◽  
Growth Adaptation

Shade-intolerant plants rapidly elongate their stems, branches, and leaf stalks to compete with their neighboring vegetation to maximize sunlight capture for photosynthesis. This rapid growth adaptation, known as the shade avoidance response (SAR), comes at a cost; reduced biomass, crop yield, and root growth. Significant progress has been made on the mechanistic understanding of hypocotyl elongation during SAR; however, the molecular account of how root growth is repressed is not well understood. Here, we explore the mechanisms by which low red:far-red induced SAR restrict the primary and lateral root (LR) growth. By analyzing whole-genome transcriptome, we identified a core set of shade-induced genes in the roots of Arabidopsis and tomato seedlings grown in the shade. Abiotic and biotic stressors also induce many of these shade-induced genes and are predominantly regulated by the WRKY transcription factors. Correspondingly, a majority of the WRKYs were also among the shade-induced genes. Functional analysis using transgenics of these shade-induced WRKYs revealed their role is essentially to restrict primary root and LR growth in the shade, and captivatingly, they did not affect hypocotyl elongation. Similarly, we also show that ethylene hormone signaling is necessary to limit root growth in the shade. Our study proposes that during SAR, shade-induced WRKY26, 45, and 75, and ethylene reprogram gene expression in the root to restrict its growth and development. The reduced growth of root organs helps the plant divert its critical resources to the elongating organs in the shoot to ensure competitiveness under limiting photosynthetic radiation

scholarly journals Plasma membrane proteomics in the maize primary root growth zone: novel insights into root growth adaptation to water stress

2016 ◽  
Vol 39 (9) ◽  
pp. 2043-2054 ◽  
Author(s):  
Priyamvada Voothuluru ◽  
Jeffrey C. Anderson ◽  
Robert E. Sharp ◽  
Scott C. Peck
Keyword(s):  
Plasma Membrane ◽  
Water Stress ◽  
Root Growth ◽  
Primary Root ◽  
Growth Zone ◽  
Membrane Proteomics ◽  
Primary Root Growth ◽  
Growth Adaptation

Tomatoes Remember being Brushed

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 471c-471
Author(s):  
Thomas Björkman ◽  
L.C. Garner
Keyword(s):  
Growth Rate ◽  
Avoidance Response ◽  
Growth Response ◽  
Shade Avoidance ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Tomato Seedlings ◽  
Close Proximity ◽  
The Individual ◽  
Touch Stimulus

Tomato seedlings grown in close proximity elongate rapidly in a shade-avoidance response. A daily touch stimulus can eliminate the extra growth associated with shade avoidance. Experiments to determine how the touch stimulus is integrated were performed on tomato seedlings grown in plug trays 22 mm apart, starting when two fully expanded leaves overlapped between plants to induce the shade-avoidance response. The standard touch stimulus was applied by brushing the surface of the canopy 10 times each morning with a piece of Styrofoam sheet. This treatment reduced the daily growth rate from 7.7 to 5.8 mm/day, but quadrupling the dose further reduced growth only slightly (J. Amer. Soc. Hort. Sci. 121:894). The ability of the plants to sum individual stimuli was tested by varying the interval between the individual strokes. Intervals of 0.01, 0.1, 1 and 10 min all produced the same growth response. Thus, the individual strokes were perceived as a single stimulus. Had they been perceived as separate stimuli, long intervals would have increased the response. There was no refractory period of insensitivity following the stimulus; that would have reduced the response at longer intervals. The height reduction was directly proportional to the number of days that the treatment was applied, indicating that each day of treatment reduced the growth rate for only 1 day (from 5.9 mm/day to 2.7 mm/day). Thus, brief stimuli are integrated during the day and expressed as a reduction of growth the next diurnal cycle.

scholarly journals Transcription Factor WRKY33 Mediates the Phosphate Deficiency-Induced Remodeling of Root Architecture by Modulating Iron Homeostasis in Arabidopsis Roots

2021 ◽  
Vol 22 (17) ◽  
pp. 9275
Author(s):  
Nuo Shen ◽  
Sifan Hou ◽  
Guoqing Tu ◽  
Wenzhi Lan ◽  
Yanping Jing
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Root Growth ◽  
Root Architecture ◽  
Iron Homeostasis ◽  
Primary Root ◽  
Negative Regulator ◽  
Phosphate Deficiency ◽  
Root Tips ◽  
Pi Deficiency

The remodeling of root architecture is regarded as a major development to improve the plant’s adaptivity to phosphate (Pi)-deficient conditions. The WRKY transcription factors family has been reported to regulate the Pi-deficiency-induced systemic responses by affecting Pi absorption or transportation. Whether these transcription factors act as a regulator to mediate the Pi-deficiency-induced remodeling of root architecture, a typical local response, is still unclear. Here, we identified an Arabidopsis transcription factor, WRKY33, that acted as a negative regulator to mediate the Pi-deficiency-induced remodeling of root architecture. The disruption of WRKY33 in wrky33-2 mutant increased the plant’s low Pi sensitivity by further inhibiting the primary root growth and promoting the formation of root hair. Furthermore, we revealed that WRKY33 negatively regulated the remodeling of root architecture by controlling the transcriptional expression of ALMT1 under Pi-deficient conditions, which further mediated the Fe3+ accumulation in root tips to inhibit the root growth. In conclusion, this study demonstrates a previously unrecognized signaling crosstalk between WRKY33 and the ALMT1-mediated malate transport system to regulate the Pi deficiency responses.

scholarly journals 2,4-Diacetylphloroglucinol Alters Plant Root Development

2008 ◽  
Vol 21 (10) ◽  
pp. 1349-1358 ◽  
Author(s):  
Jessica N. Brazelton ◽  
Emily E. Pfeufer ◽  
Teresa A. Sweat ◽  
Brian B. McSpadden Gardener ◽  
Catharina Coenen
Keyword(s):  
Root Growth ◽  
Plant Root ◽  
Primary Root ◽  
Luciferase Reporter ◽  
Root Production ◽  
Inhibitory Effects ◽  
Luciferase Reporter Gene ◽  
Root Branching ◽  
Tomato Seedlings ◽  
Primary Root Growth

Pseudomonas fluorescens isolates containing the phlD gene can protect crops from root pathogens, at least in part through production of the antibiotic 2,4-diacetylphloroglucinol (DAPG). However, the action mechanisms of DAPG are not fully understood, and effects of this antibiotic on host root systems have not been characterized in detail. DAPG inhibited primary root growth and stimulated lateral root production in tomato seedlings. Roots of the auxin-resistant diageotropica mutant of tomato demonstrated reduced DAPG sensitivity with regards to inhibition of primary root growth and induction of root branching. Additionally, applications of exogenous DAPG, at concentrations previously found in the rhizosphere of plants inoculated with DAPG-producing pseudomonads, inhibited the activation of an auxin-inducible GH3 promoter∷luciferase reporter gene construct in transgenic tobacco hypocotyls. In this model system, supernatants of 17 phlD+ P. fluorescens isolates had inhibitory effects on luciferase activity similar to synthetic DAPG. In addition, a phlD– mutant strain, unable to produce DAPG, demonstrated delayed inhibitory effects compared with the parent wild-type strain. These results indicate that DAPG can alter crop root architecture by interacting with an auxin-dependent signaling pathway.

scholarly journals MYCs and PIFs Act Independently in Arabidopsis Growth Regulation

2020 ◽  
Vol 10 (5) ◽  
pp. 1797-1807
Author(s):  
Chunmei Li ◽  
Kazunari Nozue ◽  
Julin N. Maloof
Keyword(s):  
Gene Regulation ◽  
Transcription Factors ◽  
Avoidance Response ◽  
Growth Regulation ◽  
Shade Avoidance ◽  
Triple Mutant ◽  
Post Translational Modifications ◽  
Petiole Elongation ◽  
The Relationship

Plants have a variety of strategies to avoid canopy shade and compete with their neighbors for light, collectively called the shade avoidance syndrome (SAS). Plants also have extensive systems to defend themselves against pathogens and herbivores. Defense and shade avoidance are two fundamental components of plant survival and productivity, and there are often tradeoffs between growth and defense. Recently, MYC2, a major positive regulator of defense, was reported to inhibit elongation during shade avoidance. Here, we further investigate the role of MYC2 and the related MYC3 and MYC4 in shade avoidance, and we examine the relationship between MYC2/3/4 and the PIF family of light-regulated transcription factors. We demonstrate that MYC2/3/4 inhibit both elongation and flowering. Furthermore, using both genetic and transcriptomic analysis we find that MYCs and PIFs generally function independently in growth regulation. However, surprisingly, the pif4/5/7 triple mutant restored the petiole shade avoidance response of myc2 (jin1-2) and myc2/3/4. We theorize that increased petiole elongation in myc2/3/4 could be more due to resource tradeoffs or post-translational modifications rather than interactions with PIF4/5/7 affecting gene regulation.

scholarly journals High throughput phenotyping of root growth dynamics, lateral root formation, root architecture and root hair development enabled by PlaRoM

2009 ◽  
Vol 36 (11) ◽  
pp. 938 ◽  
Author(s):  
Nima Yazdanbakhsh ◽  
Joachim Fisahn
Keyword(s):  
Root Growth ◽  
Growth Kinetics ◽  
Lateral Root ◽  
Root Architecture ◽  
Imaging Techniques ◽  
Plant Root ◽  
Primary Root ◽  
Growth Media ◽  
Root Extension ◽  
Lateral Root Development

Plant organ phenotyping by non-invasive video imaging techniques provides a powerful tool to assess physiological traits and biomass production. We describe here a range of applications of a recently developed plant root monitoring platform (PlaRoM). PlaRoM consists of an imaging platform and a root extension profiling software application. This platform has been developed for multi parallel recordings of root growth phenotypes of up to 50 individual seedlings over several days, with high spatial and temporal resolution. PlaRoM can investigate root extension profiles of different genotypes in various growth conditions (e.g. light protocol, temperature, growth media). In particular, we present primary root growth kinetics that was collected over several days. Furthermore, addition of 0.01% sucrose to the growth medium provided sufficient carbohydrates to maintain reduced growth rates in extended nights. Further analysis of records obtained from the imaging platform revealed that lateral root development exhibits similar growth kinetics to the primary root, but that root hairs develop in a faster rate. The compatibility of PlaRoM with currently accessible software packages for studying root architecture will be discussed. We are aiming for a global application of our collected root images to analytical tools provided in remote locations.

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