Studies on the Developmental Physiology of the Relationship between the Cortical Disintegration and Lateral Root Growth in Rice Seminal Roots

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.

Download Full-text

MiR393 and miR390 synergistically regulate lateral root growth in rice under different conditions

BMC Plant Biology ◽

10.1186/s12870-018-1488-x ◽

2018 ◽

Vol 18 (1) ◽

Cited By ~ 7

Author(s):

Yuzhu Lu ◽

Zhen Feng ◽

Xuanyu Liu ◽

Liying Bian ◽

Hong Xie ◽

...

Keyword(s):

Root Growth ◽

Lateral Root

Download Full-text

Regulation of lateral root development by shoot-sensed far-red light via HY5 is nitrate-dependent and involves the NRT2.1 nitrate transporter

10.1101/2021.01.31.428985 ◽

2021 ◽

Author(s):

Kasper van Gelderen ◽

Chiakai Kang ◽

Peijin Li ◽

Ronald Pierik

Keyword(s):

Root Growth ◽

Root System ◽

Lateral Root ◽

Environmental Changes ◽

Red Light ◽

Agar Plate ◽

Nitrate Transporter ◽

Loss Of Function ◽

Lateral Root Development ◽

Nitrate Signaling

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.

Download Full-text

Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

10.1101/361709 ◽

2018 ◽

Cited By ~ 2

Author(s):

Thea van den Berg ◽

Kirsten H. ten Tusscher

Keyword(s):

Cell Cycle ◽

Root Growth ◽

Lateral Root ◽

Root Formation ◽

Growth Dynamics ◽

Root Tip ◽

Cycle Duration ◽

Elongation Zone ◽

Lateral Root Formation ◽

Cell Cycle Duration

AbstractThe root system is a major determinant of plant fitness. Its capacity to supply the plant with sufficient water and nutrients strongly depends on root system architecture, which arises from the repeated branching off of lateral roots. A critical first step in lateral root formation is priming, which prepatterns sites competent of forming a lateral root. Priming is characterized by temporal oscillations in auxin, auxin signalling and gene expression in the root meristem, which through growth become transformed into a spatially repetitive pattern of competent sites. Previous studies have demonstrated the importance of auxin synthesis, transport and perception for the amplitude of these oscillations and their chances of producing an actual competent site. Additionally, repeated lateral root cap apoptosis was demonstrated to be strongly correlated with repetitive lateral root priming. Intriguingly, no single mutation has been identified that fully abolishes lateral root formation, and thusfar the mechanism underlying oscillations has remained unknown. In this study, we investigated the impact of auxin reflux loop properties combined with root growth dynamics on priming, using a computational approach. To this end we developed a novel multi-scale root model incorporating a realistic root tip architecture and reflux loop properties as well as root growth dynamics. Excitingly, in this model, repetitive auxin elevations automatically emerge. First, we show that root tip architecture and reflux loop properties result in an auxin loading zone at the start of the elongation zone, with preferential auxin loading in narrow vasculature cells. Second, we demonstrate how meristematic root growth dynamics causes regular alternations in the sizes of cells arriving at the elongation zone, which subsequently become amplified during cell expansion. These cell size differences translate into differences in cellular auxin loading potential. Combined, these properties result in temporal and spatial fluctuations in auxin levels in vasculature and pericycle cells. Our model predicts that temporal priming frequency predominantly depends on cell cycle duration, while cell cycle duration together with meristem size control lateral root spacing.

Download Full-text

Lateral root growth in Arabidopsis is controlled by short and long distance signaling through the LRR RLKs XIP1/CEPR1 and CEPR2

Plant Signaling & Behavior ◽

10.1080/15592324.2018.1489667 ◽

2018 ◽

Vol 13 (6) ◽

pp. e1489667 ◽

Cited By ~ 6

Author(s):

I. Dimitrov ◽

F. E. Tax

Keyword(s):

Root Growth ◽

Lateral Root ◽

Long Distance

Download Full-text

Effects of Trifluralin on Root Morphology and Mineral Status of Wheat (Triticum aestivum) Seedlings

Weed Science ◽

10.1017/s0043174500059178 ◽

1984 ◽

Vol 32 (3) ◽

pp. 382-387 ◽

Cited By ~ 5

Author(s):

Barry M. Olson ◽

Robert B. McKercher ◽

Edward H. Halstead

Keyword(s):

Triticum Aestivum ◽

Lateral Root ◽

Growth Period ◽

Nutrient Concentrations ◽

Root Production ◽

Root Tips ◽

Wheat Seedlings ◽

Mineral Status ◽

Seminal Roots ◽

Percent Nitrogen

Growth chamber studies using one soil investigated the effects of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) at 0.0, 0.4, and 0.8 ppmw on the root development and the mineral status of wheat (Triticum aestivumL. ‘Neepawa’) seedlings. The 0.8-ppmw trifluralin rate increased the number of seminal roots, reduced lateral root production, decreased root extension, caused root tips to swell (club-like appearance), and reduced root dry weights. However, 0.4-ppmw trifluralin caused only slight damage to the seedlings. Towards the end of the two-week growth period, damaged seedlings showed signs of recovery, which included an increased number of seminal roots, development of normal root extensions from clubbed root tips, and development of normal lateral root patterns. Trifluralin increased percent calcium and magnesium and decreased percent nitrogen, phosphorus, and potassium in wheat plants. The nutrient concentrations were more affected in 21-day-old plants than in 35-day-old plants, indicating the wheat seedlings were able to recover from trifluralin injury.

Download Full-text

Overexpression of OsPIN2 Regulates Root Growth and Formation in Response to Phosphate Deficiency in Rice

International Journal of Molecular Sciences ◽

10.3390/ijms20205144 ◽

2019 ◽

Vol 20 (20) ◽

pp. 5144

Author(s):

Huwei Sun ◽

Xiaoli Guo ◽

Fugui Xu ◽

Daxia Wu ◽

Xuhong Zhang ◽

...

Keyword(s):

Root Growth ◽

Growth And Development ◽

Plant Root ◽

Lateral Roots ◽

Root Hairs ◽

Phosphate Deficiency ◽

P Deficiency ◽

Auxin Distribution ◽

Seminal Roots ◽

Underlying Mechanisms

The response of root architecture to phosphate (P) deficiency is critical in plant growth and development. Auxin is a key regulator of plant root growth in response to P deficiency, but the underlying mechanisms are unclear. In this study, phenotypic and genetic analyses were undertaken to explore the role of OsPIN2, an auxin efflux transporter, in regulating the growth and development of rice roots under normal nutrition condition (control) and low-phosphate condition (LP). Higher expression of OsPIN2 was observed in rice plants under LP compared to the control. Meanwhile, the auxin levels of roots were increased under LP relative to control condition in wild-type (WT) plants. Compared to WT plants, two overexpression (OE) lines had higher auxin levels in the roots under control and LP. LP led to increased seminal roots (SRs) length and the root hairs (RHs) density, but decreased lateral roots (LRs) density in WT plants. However, overexpression of OsPIN2 caused a loss of sensitivity in the root response to P deficiency. The OE lines had a shorter SR length, lower LR density, and greater RH density than WT plants under control. However, the LR and RH densities in the OE lines were similar to those in WT plants under LP. Compared to WT plants, overexpression of OsPIN2 had a shorter root length through decreased root cell elongation under control and LP. Surprisingly, overexpression of OsPIN2 might increase auxin distribution in epidermis of root, resulting in greater RH formation but less LR development in OE plants than in WT plants in the control condition but levels similar of these under LP. These results suggest that higher OsPIN2 expression regulates rice root growth and development maybe by changing auxin distribution in roots under LP condition.

Download Full-text