scholarly journals Mechanical touch responses of Arabidopsis TCH1-3 mutant roots on inclined hard-agar surface

2016 ◽  
Vol 30 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Guodong Zha ◽  
Bochu Wang ◽  
Junyu Liu ◽  
Jie Yan ◽  
Liqing Zhu ◽  
...  

Abstract The gravity-induced mechanical touch stimulus can affect plant root architecture. Mechanical touch responses of plant roots are an important aspect of plant root growth and development. Previous studies have reported that Arabidopsis TCH1-3 genes are involved in mechano-related events, how-ever, the physiological functions of TCH1-3 genes in Arabidopsis root mechanoresponses remain unclear. In the present study, we applied an inclined hard agar plate method to produce mechanical touch stimulus, and provided evidence that altered mechanical environment could influence root growth. Furthermore, tch1-3 Arabidopsis mutants were investigated on inclined agar surfaces to explore the functions of TCH1-3 genes on Arabidopsis root mechanoresponses. The results showed that two tch2 mutants, cml24-2 and cml24-4, exhibited significantly reduced root length, biased skewing, and decreased density of lateral root. In addition, primary root length and density of lateral root of tch3 (cml12-2) was significantly decreased on inclined agar surfaces. This study indicates that the tch2 and tch3 mutants are hypersensitive to mechanical touch stimulus, and TCH2 (CML24-2 and CML24-4) and TCH3 (CML12-2) genes may participate in the mechanical touch response of Arabidopsis roots.

2021 ◽  
Vol 12 ◽  
Author(s):  
Lijie Li ◽  
Qian Li ◽  
Kyle E. Davis ◽  
Caitlin Patterson ◽  
Sando Oo ◽  
...  

The mechanism of miRNA-mediated root growth and development in response to nutrient deficiency in peanut (Arachis hypogaea L.) is still unclear. In the present study, we found that both nitrogen (N) and potassium (K) deficiency resulted in a significant reduction in plant growth, as indicated by the significantly decreased dry weight of both shoot and root tissues under N or K deficiency. Both N and K deficiency significantly reduced the root length, root surface area, root volume, root vitality, and weakened root respiration, as indicated by the reduced O2 consuming rate. N deficiency significantly decreased primary root length and lateral root number, which might be associated with the upregulation of miR160, miR167, miR393, and miR396, and the downregulation of AFB3 and GRF. The primary and lateral root responses to K deficiency were opposite to that of the N deficiency condition. The upregulated miR156, miR390, NAC4, ARF2, and AFB3, and the downregulated miR160, miR164, miR393, and SPL10 may have contributed to the growth of primary roots and lateral roots under K deficiency. Overall, roots responded differently to the N or K deficiency stresses in peanuts, potentially due to the miRNA-mediated pathway and mechanism.


2009 ◽  
Vol 36 (11) ◽  
pp. 938 ◽  
Author(s):  
Nima Yazdanbakhsh ◽  
Joachim Fisahn

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.


2018 ◽  
Vol 19 (11) ◽  
pp. 3656 ◽  
Author(s):  
Hua Qin ◽  
Rongfeng Huang

Roots are important plant ground organs, which absorb water and nutrients to control plant growth and development. Phytohormones have been known to play a crucial role in the regulation of root growth, such as auxin and ethylene, which are central regulators of this process. Recent findings have revealed that root development and elongation regulated by ethylene are auxin dependent through alterations of auxin biosynthesis, transport and signaling. In this review, we focus on the recent advances in the study of auxin and auxin–ethylene crosstalk in plant root development, demonstrating that auxin and ethylene act synergistically to control primary root and root hair growth, but function antagonistically in lateral root formation. Moreover, ethylene modulates auxin biosynthesis, transport and signaling to fine-tune root growth and development. Thus, this review steps up the understanding of the regulation of auxin and ethylene in root growth.


2021 ◽  
Author(s):  
Kasper van Gelderen ◽  
Chiakai Kang ◽  
Peijin Li ◽  
Ronald Pierik

AbstractPlants are very effective in responding to environmental changes during competition for light and nutrients. Low Red:Far-Red (low R:FR)-mediated neighbor detection allows plants to compete successfully with other plants for available light. This above-ground signal can also reduce lateral root growth by inhibiting lateral root emergence, a process that might help the plant invest resources in shoot growth. Nitrate is an essential nutrient for plant growth and Arabidopsis thaliana responds to low nitrate conditions by enhancing nutrient uptake and reducing lateral and main root growth. There are indications that low R:FR signaling and low nitrate signaling can affect each other. It is unknown which response is prioritized when low R:FR light- and low nitrate signaling co-occur. We investigated the effect of low nitrate conditions on the low R:FR response of the A. thaliana root system in agar plate media, combined with the application of supplemental Far-Red (FR) light to the shoot. We observed that under low nitrate conditions main and lateral root growth was reduced, but more importantly, that the response of the root system to low R:FR was suppressed. Consistently, a loss-of-function mutant of a nitrate transporter gene NRT2.1 lacked low R:FR-induced lateral root reduction and its root growth was hypersensitive to low nitrate. ELONGATED HYPOCOTYL5 (HY5) plays an important role in the root response to low R:FR and we found that it was less sensitive to low nitrate conditions with regards to lateral root growth. In addition, we found that low R:FR increases NRT2.1 expression and that low nitrate enhances HY5 expression. HY5 also affects NRT2.1 expression, however, it depended on the presence of ammonium in which direction this effect was. Replacing part of the nitrogen source with ammonium also removed the effect of low R:FR on the root system, showing that changes in nitrogen sources can be crucial for root plasticity. Together our results show that nitrate signaling can repress low R:FR responses and that this involves signaling via HY5 and NRT2.1.


1997 ◽  
Vol 15 (4) ◽  
pp. 197-199
Author(s):  
Matt Kelting ◽  
J. Roger Harris ◽  
Jody Fanelli ◽  
Bonnie Appleton ◽  
Alex Niemiera

Abstract Humate-based products have been aggressively marketed to nursery producers as biostimulants which increase plant growth. Reports of their effect on container-grown trees in organic substrate are few. We tested four distinct types of biostimulants on top and root growth of Turkish hazelnut (Corylus colurna L.), grown in containers with pine-bark substrate. Treatments included: 1) an untreated control; 2) humate, applied as a dry topdress; 3) humate, formulated as a wettable powder and applied as a substrate drench; 4) humate, applied as a pre-plant root soak; 5) humate, to which various purported root growth-promoting additives had been added, also applied as a root soak. All treatments were tested within low, medium, and high fertilizer application regimes. No treatment increased top growth compared to untreated trees, and the root-soak treatments had the lowest top growth. At high and low fertilizer application rates, root length was similar for all treatments except for root-soak treatments, which had lower root lengths. At the medium fertilizer rate, root length was greatest for trees treated with granular humate applied as a dry topdressing and lowest for trees treated with root soaks.


Author(s):  
Mercedes Schroeder ◽  
Melissa Y. Gomez ◽  
Nathan K. McLain ◽  
Emma Gachomo

Beneficial rhizobacteria can stimulate changes in plant root development. While root system growth is mediated by multiple factors, the regulated distribution of the phytohormone auxin within root tissues plays a principal role. Auxin transport facilitators help to generate the auxin gradients and maxima that determine root structure. Here, we show that the plant growth-promoting rhizobacterial strain Bradyrhizobium japonicum IRAT FA3 influences specific auxin efflux transporters to alter Arabidopsis thaliana root morphology. Gene expression profiling of host transcripts in control and B. japonicum-inoculated roots of the wild type A. thaliana accession Col-0 confirmed upregulation of PIN2, PIN3, PIN7 and ABCB19 with B. japonicum and identified genes potentially contributing to a diverse array of auxin-related responses. Co-cultivation of the bacterium with loss-of-function auxin efflux transport mutants revealed that B. japonicum requires PIN3, PIN7 and ABCB19 to increase lateral root development and utilizes PIN2 to reduce primary root length. Accelerated lateral root primordia production due to B. japonicum was not observed in single pin3, pin7 or abcb19 mutants, suggesting independent roles for PIN3, PIN7 and ABCB19 during the plant-microbe interaction. Our work demonstrates B. japonicum’s influence over host transcriptional reprogramming during plant interaction with this beneficial microbe and the subsequent alterations to root system architecture.


2021 ◽  
Vol 12 ◽  
Author(s):  
Kasper van Gelderen ◽  
Chiakai Kang ◽  
Peijin Li ◽  
Ronald Pierik

Plants are very effective in responding to environmental changes during competition for light and nutrients. Low Red:Far-Red (low R:FR)-mediated neighbor detection allows plants to compete successfully with other plants for available light. This above-ground signal can also reduce lateral root growth by inhibiting lateral root emergence, a process that might help the plant invest resources in shoot growth. Nitrate is an essential nutrient for plant growth and Arabidopsis thaliana responds to low nitrate conditions by enhancing nutrient uptake and reducing lateral and main root growth. There are indications that low R:FR signaling and low nitrate signaling can affect each other. It is unknown which response is prioritized when low R:FR light- and low nitrate signaling co-occur. We investigated the effect of low nitrate conditions on the low R:FR response of the A. thaliana root system in agar plate media, combined with the application of supplemental Far-Red (FR) light to the shoot. We observed that under low nitrate conditions main and lateral root growth was reduced, but more importantly, that the response of the root system to low R:FR was not present. Consistently, a loss-of-function mutant of a nitrate transporter gene NRT2.1 lacked low R:FR-induced lateral root reduction and its root growth was hypersensitive to low nitrate. ELONGATED HYPOCOTYL5 (HY5) plays an important role in the root response to low R:FR and we found that it was less sensitive to low nitrate conditions with regards to lateral root growth. In addition, we found that low R:FR increases NRT2.1 expression and that low nitrate enhances HY5 expression. HY5 also affects NRT2.1 expression, however, it depended on the presence of ammonium in which direction this effect was. Replacing part of the nitrogen source with ammonium also removed the effect of low R:FR on the root system, showing that changes in nitrogen sources can be crucial for root plasticity. Together our results show that nitrate signaling can repress low R:FR responses and that this involves signaling via HY5 and NRT2.1.


HortScience ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 547-551
Author(s):  
Qin Shi ◽  
Yunlong Yin ◽  
Zhiquan Wang ◽  
Wencai Fan ◽  
Jinbo Guo ◽  
...  

Roots are vital organs for resource uptake. However, the knowledge regarding the extent by which responses in roots influence plant resistance is still poorly known. In this study, we examined the morphological and physiological responses of lateral roots of Taxodium hybrid ‘Zhongshanshan 406’ (Taxodium mucronatum♀ and Taxodium distichum♂, T. 406) to 8 (DS-8) and 12 days (DS-12) drought. Control plants (CK-8 and CK-12) were well-watered throughout the experiment. Results indicated that drought resulted in significantly decreased root length, surface area, volume, and biomass and a relatively high death rate of roots (>2 mm). Specific root length (SRL) and specific root surface area (SRA) of drought-stressed T. 406 plants were reduced to enhance resource uptake. Meanwhile, root relative water content (RWC) of T. 406 plants in CK-12 treatment was 5.81 times of those in DS-12 treatment. Under drought stress and root superoxide dismutase and ascorbic acid (ASA) activities, proline and hydrogen peroxide (H2O2) contents consistently increased to benefit the elimination of O2−. At the ultrastructural level, the organelle structure of T. 406 plant root tip was visibly damaged because of dehydration. The nucleus swelled and then exhibited uncommon features of disorganization and disruption. In short, our results provided substantial information about lateral root traits of T. 406 plants in response to drought stress, which is crucial to improve the drought resistance of Taxodium hybrid in the future breeding.


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