Seminal and Nodal Roots of Barley Differ in Anatomy, Proteome and Nitrate Uptake Capacity

Abstract The root system of barley plants is composed of embryogenic, seminal roots as well as lateral and nodal roots that are formed postembryonically from seminal roots and from the basal part of shoots, respectively. Due to their distinct developmental origin, seminal and nodal roots may differ in function during plant development; however, a clear comparison between these two root types has not yet been undertaken. In this study, anatomical, proteomic and physiological traits were compared between seminal and nodal roots of similar developmental stages. Nodal roots have larger diameter, larger metaxylem area and a larger number of metaxylem vessels than seminal roots. Proteome profiling uncovered a set of root-type-specific proteins, including proteins related to the cell wall and cytoskeleton organization, which could potentially be implicated with differential metaxylem development. We also found that nodal roots have higher levels of auxin, which is known to trigger metaxylem development. At millimolar nitrate supply, nodal roots had approximately 2-fold higher nitrate uptake and root-to-shoot translocation capacities than seminal roots, whereas no differences were found at micromolar nitrate supply. Since these marked differences were not reflected by the transcript levels of low-affinity nitrate transporter genes, we hypothesize that the larger metaxylem volume of nodal roots enhances predominantly the low-affinity uptake and translocation capacities of nutrients that are transported with the bulk flow of water, like nitrate.

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Nitrate supply and uptake in the Atlantic Arctic sea ice zone: seasonal cycle, mechanisms and drivers

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0361 ◽

2020 ◽

Vol 378 (2181) ◽

pp. 20190361 ◽

Cited By ~ 1

Author(s):

Sian F. Henley ◽

Marie Porter ◽

Laura Hobbs ◽

Judith Braun ◽

Robin Guillaume-Castel ◽

...

Keyword(s):

Sea Ice ◽

Primary Production ◽

Arctic Ocean ◽

Nutrient Availability ◽

Seasonal Cycle ◽

Nitrate Uptake ◽

Arctic Sea Ice ◽

The Arctic ◽

Surface Ocean ◽

Nitrate Supply

Nutrient supply to the surface ocean is a key factor regulating primary production in the Arctic Ocean under current conditions and with ongoing warming and sea ice losses. Here we present seasonal nitrate concentration and hydrographic data from two oceanographic moorings on the northern Barents shelf between autumn 2017 and summer 2018. The eastern mooring was sea ice-covered to varying degrees during autumn, winter and spring, and was characterized by more Arctic-like oceanographic conditions, while the western mooring was ice-free year-round and showed a greater influence of Atlantic water masses. The seasonal cycle in nitrate dynamics was similar under ice-influenced and ice-free conditions, with biological nitrate uptake beginning near-synchronously in early May, but important differences between the moorings were observed. Nitrate supply to the surface ocean preceding and during the period of rapid drawdown was greater at the ice-free more Atlantic-like western mooring, and nitrate drawdown occurred more slowly over a longer period of time. This suggests that with ongoing sea ice losses and Atlantification, the expected shift from more Arctic-like ice-influenced conditions to more Atlantic-like ice-free conditions is likely to increase nutrient availability and the duration of seasonal drawdown in this Arctic shelf region. The extent to which this increased nutrient availability and longer drawdown periods will lead to increases in total nitrate uptake, and support the projected increases in primary production, will depend on changes in upper ocean stratification and their effect on light availability to phytoplankton as changes in climate and the physical environment proceed. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.

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Stage-specific changes in cytoplasmic protein synthesis in Entomophaga aulicae protoplasts

Canadian Journal of Microbiology ◽

10.1139/m89-057 ◽

1989 ◽

Vol 35 (3) ◽

pp. 373-378

Author(s):

Richard A. Nolan

Keyword(s):

Protein Synthesis ◽

Developmental Stages ◽

Late Fusion ◽

One Dimensional ◽

Early Fusion ◽

Specific Proteins ◽

Fungal Protoplasts ◽

General Protein ◽

The Individual ◽

Synthesis Stage

The patterns of protein synthesis associated with three sequential stages in protoplast morphogenesis (spindle-shaped, early fusion sphere, and late fusion sphere protoplasts) of the fungus Entomophaga aulicae were studied using both one-dimensional gels with general protein staining and two-dimensional gels with [35S]methionine protein labelling and fluorography. A total of 332 proteins were observed with 63.5% (211) common to all three developmental stages. Of the individual totals, 3.3% (8 out of 245), 7.3% (22 out of 301), and 4.5% (13 out of 286) of the proteins were unique to the spindle-shaped, early fusion sphere, and late fusion sphere protoplasts, respectively. The molecular mass and pI distribution profiles for early fusion sphere protoplast proteins are discussed.Key words: protein synthesis, stage-specific proteins, fungal protoplasts, Entomophaga aulicae.

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Characterization of Temporal Protein Production in Pseudomonas aeruginosa Biofilms

Journal of Bacteriology ◽

10.1128/jb.187.23.8114-8126.2005 ◽

2005 ◽

Vol 187 (23) ◽

pp. 8114-8126 ◽

Cited By ~ 139

Author(s):

Christopher J. Southey-Pillig ◽

David G. Davies ◽

Karin Sauer

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Biofilm Formation ◽

Protein Production ◽

Developmental Stages ◽

Developmental Process ◽

Developmental Cycle ◽

Specific Proteins ◽

Biofilm Development ◽

The Impact

ABSTRACT Phenotypic and genetic evidence supporting the notion of biofilm formation as a developmental process is growing. In the present work, we provide additional support for this hypothesis by identifying the onset of accumulation of biofilm-stage specific proteins during Pseudomonas aeruginosa biofilm maturation and by tracking the abundance of these proteins in planktonic and three biofilm developmental stages. The onset of protein production was found to correlate with the progression of biofilms in developmental stages. Protein identification revealed that proteins with similar function grouped within similar protein abundance patterns. Metabolic and housekeeping proteins were found to group within a pattern separate from virulence, antibiotic resistance, and quorum-sensing-related proteins. The latter were produced in a progressive manner, indicating that attendant features that are characteristic of biofilms such as antibiotic resistance and virulence may be part of the biofilm developmental process. Mutations in genes for selected proteins from several protein production patterns were made, and the impact of these mutations on biofilm development was evaluated. The proteins cytochrome c oxidase, a probable chemotaxis transducer, a two-component response regulator, and MexH were produced only in mature and late-stage biofilms. Mutations in the genes encoding these proteins did not confer defects in growth, initial attachment, early biofilm formation, or twitching motility but were observed to arrest biofilm development at the stage of cell cluster formation we call the maturation-1 stage. The results indicated that expression of theses genes was required for the progression of biofilms into three-dimensional structures on abiotic surfaces and the completion of the biofilm developmental cycle. Reverse transcription-PCR analysis confirmed the detectable change in expression of the respective genes ccoO, PA4101, and PA4208. We propose a possible mechanism for the role of these biofilm-specific proteins in biofilm formation.

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Effect of copper deficiency in wheat on the infection of roots by Gaeumannomyces graminis var. tritici

Australian Journal of Agricultural Research ◽

10.1071/ar9840735 ◽

1984 ◽

Vol 35 (6) ◽

pp. 735 ◽

Cited By ~ 12

Author(s):

MJ Wood ◽

AD Robson

Keyword(s):

Plant Growth ◽

Copper Deficiency ◽

Gaeumannomyces Graminis ◽

Fresh Weight ◽

Nodal Roots ◽

Copper Status ◽

Seminal Roots ◽

Effect Of Copper ◽

Gaeumannomyces Graminis Var Tritici ◽

Take All

Wheat was grown in a soil at five levels of copper (ranging from levels deficient, to those luxurious, for plant growth), in the presence or absence of introduced take-all inoculum (oat kernels colonized by Gaeumannomyces graminis var. tritica). The incidence and severity of take-all were related to the copper supply and hence the copper status of the wheat. Plants grown without applied copper were more severely infected by take-all than were those grown with an adequate or luxurious supply of copper. The number of lesions per gram fresh weight of roots was reduced from 6.5 to 2.4 by increasing the copper supply from that severely deficient, to that adequate for plant growth. In seminal roots, increasing the copper supply from levels severely deficient to those adequate or luxurious for plant growth, decreased the length of proximal lesions (those closest to the seed). By contrast, in nodal roots, a similar increase in copper supply had no effect on the length of proximal lesions, but increased the length of uninfected root between the crown and proximal lesions. In both seminal and nodal roots, copper supply did not affect the intensity of lesions.

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Water Stressed Nodal Roots of Wheat: Effects on Leaf Growth

Functional Plant Biology ◽

10.1071/pp96063 ◽

1997 ◽

Vol 24 (1) ◽

pp. 49 ◽

Cited By ~ 13

Author(s):

K. M. Volkmar

Keyword(s):

Growth Rate ◽

Water Content ◽

Relative Water Content ◽

Leaf Growth ◽

Seminal Root ◽

Nodal Roots ◽

Nodal Root ◽

Relative Water ◽

Seminal Roots ◽

Leaf Relative Water Content

This experiment as undertaken to determine the efects of soil drying around the nodal and/or seminal root systems on the shoot growth of wheat (Triticum aestivum L.). Two split-root experiments were conducted, the first on newly emerged nodal roots of 18-day-old wheat plants, the second on 25-day-old plants. In both experiments, nodal and seminal roots were isolated from one another and water was withheld from either the nodal root chamber, the seminal root chamber, or both, over 6 days. In the first experiment, leaf growth was unaffected by withholding water from very short nodal roots, even though leaf relative water content of the droughted plants decreased. By comparison, both leaf elongation rate and relative water content decreased by withholding water from the seminal roots. On plants that were 1 week older, leaf growth rate and leaf relative water content decreased when nodal roots were drought-stressed. Leaf growth rate of seminal root droughted plants was more impaired than their nodal root counterparts, even though leaf relative water contents of the two treatments were the same. In both experiments, drought stress applied to the nodal root system enhanced nodal root growth more than seminal roots. These results suggest that seminal and nodal roots perceive and respond to drought stress differently with respect to the nature of the message conveyed to the shoots.

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LeNRT1.1 Improves Nitrate Uptake in Grafted Tomato Plants under High Nitrogen Demand

International Journal of Molecular Sciences ◽

10.3390/ijms19123921 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3921 ◽

Cited By ~ 2

Author(s):

Francisco Albornoz ◽

Marlene Gebauer ◽

Carlos Ponce ◽

Ricardo Cabeza

Keyword(s):

Plasma Membrane ◽

Root Respiration ◽

Nitrate Uptake ◽

N Uptake ◽

Uptake Capacity ◽

Tomato Plants ◽

Respiration Rates ◽

Assimilation Capacity ◽

N Demand ◽

Root Plasma Membrane

Grafting has become a common practice among tomato growers to obtain vigorous plants. These plants present a substantial increase in nitrogen (N) uptake from the root zone. However, the mechanisms involved in this higher uptake capacity have not been investigated. To elucidate whether the increase in N uptake in grafted tomato plants under high N demand conditions is related to the functioning of low- (high capacity) or high-affinity (low capacity) root plasma membrane transporters, a series of experiments were conducted. Plants grafted onto a vigorous rootstock, as well as ungrafted and homograft plants, were exposed to two radiation levels (400 and 800 µmol m−2 s−1). We assessed root plasma membrane nitrate transporters (LeNRT1.1, LeNRT1.2, LeNRT2.1, LeNRT2.2 and LeNRT2.3) expression, Michaelis‒Menten kinetics parameters (Vmax and Km), root and leaf nitrate reductase activity, and root respiration rates. The majority of nitrate uptake is mediated by LeNRT1.1 and LeNRT1.2 in grafted and ungrafted plants. Under high N demand conditions, vigorous rootstocks show similar levels of expression for LeNRT1.1 and LeNRT1.2, whereas ungrafted plants present a higher expression of LeNRT1.2. No differences in the uptake capacity (evaluated as Vmax), root respiration rates, or root nitrate assimilation capacity were found among treatments.

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