scholarly journals A mechanism for sensing of and adaptation to K+ deprivation in plants

2020 ◽  
Author(s):  
Feng-Liu Wang ◽  
Ya-Lan Tan ◽  
Lukas Wallrad ◽  
Xin-Qiao Du ◽  
Anna Eickelkamp ◽  
...  
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Environmental Conditions ◽  
Plant Nutrition ◽  
Potassium Ions ◽  
Receptor Kinase ◽  
Cellular Processes ◽  
Efficient Uptake ◽  
Developmental Differentiation ◽  
Low K

SummaryPotassium ions (K+) are essential for manifold cellular processes. Organismal K+ homoeostasis requires sensing of K+ availability, efficient uptake and defined distribution. Roots are the organ for K+ uptake in plants and soil K+ availability shapes root growth and architecture1. Important channels and transporters conveying cellular K+ fluxes have been described2,3. Understanding K+ sensing and the mechanisms that orchestrate downstream responses exemplifies how environmental conditions integrate with root development and is essential to advance plant nutrition for sustainable agriculture. Here, we report where plants sense K+ deprivation and how this translates into spatially defined ROS signals to trigger HAK5 K+ uptake transporter induction and accelerated maturation of the Casparian strip (CS) paracellular barrier. We define the organ scale K+ pattern of roots and identify a postmeristematic K+-sensing niche (KSN) defined by rapid K+ decline and Ca2+ signals. We discover a Ca2+-triggered bifurcating low-K+ signalling (LKS) axis in that LK-enhanced CIF peptide signalling reinforces SGN3-LKS4/SGN1 receptor kinase complex activation. As consequence, activation of the NOXs RBOHC and RBOHD conveys transcriptome adaptation including HAK5 induction and accelerated CS maturation superimposed on the RBOHF-executed default CS formation. These mechanisms synchronise developmental differentiation and transcriptome reprogramming for maintaining K+ homoeostasis and optimising nutrient foraging by roots.

scholarly journals A low-cost aeroponic phenotyping system for storage root development: unravelling the below-ground secrets of cassava (Manihot esculenta)

Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Michael Gomez Selvaraj ◽  
Maria Elker Montoya-P ◽  
John Atanbori ◽  
Andrew P. French ◽  
Tony Pridmore
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Low Cost ◽  
Root Traits ◽  
Suitable Model ◽  
Root Initiation ◽  
Storage Root ◽  
Economic Traits ◽  
Storage Roots ◽  
Storage Root Development

Abstract Background Root and tuber crops are becoming more important for their high source of carbohydrates, next to cereals. Despite their commercial impact, there are significant knowledge gaps about the environmental and inherent regulation of storage root (SR) differentiation, due in part to the innate problems of studying storage roots and the lack of a suitable model system for monitoring storage root growth. The research presented here aimed to develop a reliable, low-cost effective system that enables the study of the factors influencing cassava storage root initiation and development. Results We explored simple, low-cost systems for the study of storage root biology. An aeroponics system described here is ideal for real-time monitoring of storage root development (SRD), and this was further validated using hormone studies. Our aeroponics-based auxin studies revealed that storage root initiation and development are adaptive responses, which are significantly enhanced by the exogenous auxin supply. Field and histological experiments were also conducted to confirm the auxin effect found in the aeroponics system. We also developed a simple digital imaging platform to quantify storage root growth and development traits. Correlation analysis confirmed that image-based estimation can be a surrogate for manual root phenotyping for several key traits. Conclusions The aeroponic system developed from this study is an effective tool for examining the root architecture of cassava during early SRD. The aeroponic system also provided novel insights into storage root formation by activating the auxin-dependent proliferation of secondary xylem parenchyma cells to induce the initial root thickening and bulking. The developed system can be of direct benefit to molecular biologists, breeders, and physiologists, allowing them to screen germplasm for root traits that correlate with improved economic traits.

SNF1-related protein kinase 1: the many-faced signaling hub regulating developmental plasticity in plants

2021 ◽  
Author(s):  
Muhammed Jamsheer K ◽  
Manoj Kumar ◽  
Vibha Srivastava
Keyword(s):  
Protein Kinase ◽  
Environmental Conditions ◽  
Protein Trafficking ◽  
Developmental Plasticity ◽  
Inositol Phosphate ◽  
Future Research ◽  
Primary Metabolism ◽  
Related Protein ◽  
Comprehensive Overview ◽  
Cellular Processes

AbstractThe Snf1-related protein kinase 1 (SnRK1) is the plant homolog of the heterotrimeric AMP-activated protein kinase/sucrose non-fermenting 1 (AMPK/Snf1), which works as a major regulator of growth under nutrient-limiting conditions in eukaryotes. Along with its conserved role as a master regulator of sugar starvation responses, SnRK1 is involved in controlling the developmental plasticity and resilience under diverse environmental conditions in plants. In this review, through mining and analyzing the interactome and phosphoproteome data of SnRK1, we are highlighting its role in fundamental cellular processes such as gene regulation, protein synthesis, primary metabolism, protein trafficking, nutrient homeostasis, and autophagy. Along with the well-characterized molecular interaction in SnRK1 signaling, our analysis highlights several unchartered regions of SnRK1 signaling in plants such as its possible communication with chromatin remodelers, histone modifiers, and inositol phosphate signaling. We also discuss potential reciprocal interactions of SnRK1 signaling with other signaling pathways and cellular processes, which could be involved in maintaining flexibility and homeostasis under different environmental conditions. Overall, this review provides a comprehensive overview of the SnRK1 signaling network in plants and suggests many novel directions for future research.

Foliar vs. Root Sensitivity of Hairy Bittercress (Cardamine hirsuta) to Isoxaben

2006 ◽  
Vol 20 (2) ◽  
pp. 326-333 ◽  
Author(s):  
Glenn Wehtje ◽  
Charles H. Gilliam ◽  
Michael E. Miller ◽  
James E. Altland
Keyword(s):  
Root Growth ◽  
Environmental Conditions ◽  
Day Length ◽  
Root Growth Inhibition ◽  
Root Absorption ◽  
Nursery Production ◽  
Plant Maturity ◽  
Higher Temperature ◽  
Inhibit Root Growth ◽  
Hydroponically Grown

It has been previously reported that POST-applied isoxaben can effectively control established hairy bittercress. Experiments were conducted to determine the relative importance of root vs. foliar entry of POST-applied isoxaben. At a common isoxaben rate of 0.56 kg/ha, foliar-only and foliar plus soil applications provided 10.5 and 23.3% control, respectively, as determined by fresh weight reduction. In contrast, soil-only application provided 47.0% control. Hairy bittercress foliar absorption of14C–isoxaben did not exceed 15% of the amount applied after 72 h. Therefore, the comparatively less effectiveness of foliar-only applications may be attributed primarily to limited absorption. Minimal isoxaben concentration required to inhibit root growth of hydroponically grown hairy bittercress was 0.0025 mg/L. Higher concentrations were required to produce a response in the foliage. Sorption of isoxaben by pine bark rooting substrate, typical of what is used in container nursery production, exceeded 99% of amount applied after 36 h. Even with 99% sorption, the probable concentration within the aqueous phase remains sufficient to inhibit hairy bittercress root growth. Additional studies with14C–isoxaben established that approximately 35% of the root-absorbed isoxaben was translocated into the foliage. Translocation from the roots into the foliage was reduced to 16% when the experiment was repeated during environmental conditions less favorable for vegetative growth (i.e., longer day length and higher temperature). Results indicate that the control of hairy bittercress with POST-applied isoxaben is likely the result of root absorption and root-growth inhibition. Expression of phytotoxicity within the foliage is also a component, but is dependent upon the root-absorbed isoxaben being translocated into the foliage. Extent of this translocation is dependent upon plant maturity and prevalent environmental conditions.

Flooding Tolerance of Fall Panicum and Texas Panicum

Weed Science ◽  
1972 ◽  
Vol 20 (1) ◽  
pp. 1-3 ◽  
Author(s):  
C. S. Hoveland ◽  
G. A. Buchanan
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Root Diameter ◽  
Crop Plants ◽  
Flooding Tolerance ◽  
Flooded Soil ◽  
Panicum Dichotomiflorum

Fall panicum (Panicum dichotomiflorum Michx.) and Texas panicum (Panicum texanum Buckl.) were grown in the greenhouse under flooding treatments of 0, 6, and 9 days in 10 for 1 month. Fall panicum was more tolerant of flooded soil than was Texas panicum. Root development of Texas panicum was reduced by 50% under all flooding treatments. Herbage and root growth of fall panicum with flooding was similar to that on well-drained soil. Fall panicum root diameter was greater than that of Texas panicum, but both species increased under flooding. Tolerance of fall panicum to flooding may partially explain why it competes so well with crop plants during wet periods.

scholarly journals In-Field Observation of Root Growth and Nitrogen Uptake Efficiency of Winter Oilseed Rape

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 105
Author(s):  
Julien Louvieaux ◽  
Antoine Leclercq ◽  
Loïc Haelterman ◽  
Christian Hermans
Keyword(s):  
Root Growth ◽  
Oilseed Rape ◽  
Root Development ◽  
Nitrogen Uptake ◽  
Root Morphology ◽  
Growth Stages ◽  
Winter Oilseed Rape ◽  
Nitrogen Uptake Efficiency ◽  
Uptake Efficiency ◽  
N Concentration

Field trials were conducted with two nitrogen applications (0 or 240 kg N ha−1) and three modern cultivars of winter oilseed rape (Brassica napus L.) previously selected from a root morphology screen at a young developmental stage. The purpose is to examine the relationship between root morphology and Nitrogen Uptake Efficiency (NUpE) and to test the predictiveness of some canopy optical indices for seed quality and yield. A tube-rhizotron system was used to incorporate below-ground root growth information. Practically, clear tubes of one meter in length were installed in soil at an angle of 45°. The root development was followed with a camera at key growth stages in autumn (leaf development) and spring (stem elongation and flowering). Autumn was a critical time window to observe the root development, and exploration in deeper horizons (36–48 cm) was faster without any fertilization treatment. Analysis of the rhizotron images was challenging and it was not possible to clearly discriminate between cultivars. Canopy reflectance and leaf optical indices were measured with proximal sensors. The Normalized Difference Vegetation Index (NDVI) was a positive indicator of biomass and seed yield while the Nitrogen Balance Index (NBI) was a positive indicator of above-ground biomass N concentration at flowering and seed N concentration at harvest.

scholarly journals miR168 targets Argonaute1A mediated miRNAs regulation pathways in response to potassium deficiency stress in tomato

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Xin Liu ◽  
Chunchang Tan ◽  
Xin Cheng ◽  
Xiaoming Zhao ◽  
Tianlai Li ◽  
...  
Keyword(s):  
Root Growth ◽  
Transgenic Tomato ◽  
Integrated Analysis ◽  
Regulation Mechanism ◽  
Sequencing Analysis ◽  
Growth Modulation ◽  
Tomato Plants ◽  
Transgenic Tomato Plants ◽  
Low K

Abstract Background Potassium (K+) is an essential ion for most plants, as it is involved in the regulation of growth and development. K+ homeostasis in plant cells has evolved to facilitate plant adaptation to K+-deficiency stress. Argonaute1 (AGO1) is regulated by miR168 to modulate the small RNA regulatory pathway by RNA silencing complex (RISC) in tomatoes. However, the role of miR168-mediated regulation of AGO1 in the context of K+ deficiency stress in tomatoes has not been elucidated yet. Results SlmiR168 and its target gene SlAGO1A were differentially expressed among low-K+-tolerant JZ34 and low-K+-sensitive JZ18 tomato plants. Transgenic tomato plants constitutively expressing pri-SlmiR168a showed stronger root system growth, better leaves development, and higher K+ contents in roots under K+-deficiency stress than those of the transgenic tomato lines expressing rSlAGO1A (SlmiR168-resistant) and the wild type (WT). Deep sequencing analysis showed that 62 known microRNAs (miRNAs) were up-regulated in 35S:rSlAGO1 compared with WT tomatoes. The same miRNAs were down-regulated in 35S:SlmiR168a compared with WT plants. The integrated analysis found 12 miRNA/mRNA pairs from the 62 miRNAs, including the root growth and cytokinin (CTK)/abscisic acid (ABA) pathways. Conclusions The regulation mediated by SlmiR168 of SlAGO1A contributes to the plant development under low-K+ stress. Moreover, this regulation mechanism may influence downstream miRNA pathways in response to low-K+ stress through the CTK/ABA and root growth modulation pathways.

Physiological processes in plantation establishment and the development of specifications for forest planting stock

1990 ◽  
Vol 20 (4) ◽  
pp. 415-427 ◽  
Author(s):  
A. N. Burdett
Keyword(s):  
Root Growth ◽  
Environmental Conditions ◽  
Water Status ◽  
Plant Water Status ◽  
Forest Site ◽  
Plant Water ◽  
Plantation Establishment ◽  
Tissue Water ◽  
Planting Stock ◽  
Central Process

Both the morphological and physiological characteristics of forest planting stock vary widely with nursery culture and environment. Through the control of environmentally determined variation in phenotype, stock can be adapted to both the stress of transplanting from nursery to forest site and the particular environmental conditions of the forest site. Evidence is discussed that indicates that the stress of transplanting is primarily water stress, resulting from (i) the confinement of roots to the planting hole, (ii) poor root–soil contact, and (iii) low root permeability. These deficiencies are overcome by root growth, which is thus a central process in plantation establishment. Root growth depends largely on current photosynthesis. Photosynthesis depends on the assimilation of carbon dioxide at the expense of lost water in transpiration. Transpiration is limited by water uptake and hence depends on root growth. Root growth and photosynthesis in newly planted trees are thus mutually dependent. Because of this relationship, plant water status immediately after planting, or as soon as conditions favorable to root growth occur, is a crucial factor in determining plantation establishment success. High plant tissue water status immediately after planting, or as soon as environmental conditions permit root growth, allows the onset of a positive cycle of root growth supported by photosynthesis and photosynthesis supported by root growth; whereas low tissue water potential immediately after planting can lead to the inhibition or root growth by a lack of photosynthesis and the inhibition of photosynthesis by a lack of root growth. Stock characteristics that enhance plant water status immediately after planting are reviewed and the scope for their control considered. Stock characteristics affecting adaptation to particular planting site conditions, or capable of affecting postestablishment plantation performance, are also discussed.

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