Paper · 2021 · Frontiers in Plant Science

Genetic Variation in Root Architectural Traits in Lactuca and Their Roles in Increasing Phosphorus-Use-Efficiency in Response to Low Phosphorus Availability

Amira Beroueg; François Lecompte; Alain Mollier; et al.

11
claims
11
verbatim quotes
21
citations
2
research areas
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Open access · cc-by

Abstract

Low phosphorus (P) bioavailability in the soil and concerns over global P reserves have emphasized the need to cultivate plants that acquire and use P efficiently. Root architecture adaptation to low P can be variable depending on species or even genotypes. To assess the genetic variability of root architectural traits and their responses to low P in the Lactuca genus, we examined fourteen genotypes including wild species, ancient and commercial lettuce cultivars at low (LP, 0.1 mmol. L –1 ) and high P (HP, 1 mmol. L –1 ). Plants were grown in cylindrical pots adapted for the excavation and observation of root systems, with an inert substrate. We identified substantial genetic variation in all the investigated root traits, as well as an effect of P availability on these traits, except on the diameter of thinner roots. At low P, the main responses were a decrease in taproot diameter, an increase in taproot dominance over its laterals and an increase in the inter-branch distance. Although the genotype x P treatment effect was limited to root depth, we identified a tradeoff between the capacity to maintain a thick taproot at low P and the dominance of the taproot over its laterals. Regardless of the P level, the phosphorus-use-efficiency (PUE) varied among lettuce genotypes and was significantly correlated with total root biomass regardless of the P level. As taproot depth and maximum apical diameter were the principal determinants of total root biomass, the relative increase in PUE at low P was observed in genotypes that showed the thickest apical diameters and/or those whose maximal apical diameter was not severely decreased at low P availability. This pre-eminence of the taproot in the adaptation of Lactuca genotypes to low P contrasts with other species which rely more on lateral roots to adapt to P stress.

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Claims 11

Observationobservedoriginal resultmeasured

Claim · model-written summary

Root traits varied substantially among genotypes.

Outcome
genetic variation in all the investigated root traitse0

Not reportedTaxon

Verbatim

e0

“We identified substantial genetic variation in all the investigated root traits, as well as an effect of P availability on these traits, except on the diameter of thinner roots.”

✓ located verbatim in the source · abstract, characters 652–829 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

P availability affected root traits except thinner-root diameter.

Treatment
P availabilitye0
Outcome
root traitse0
Qualifier
except on the diameter of thinner rootse0

Not reportedTaxonDirection

Verbatim

e0

“We identified substantial genetic variation in all the investigated root traits, as well as an effect of P availability on these traits, except on the diameter of thinner roots.”

✓ located verbatim in the source · abstract, characters 652–829 · show in text ↑
Intervention effectobservedoriginal resultnegativemeasured

Claim · model-written summary

Low P decreased taproot diameter.

Treatment
low Pe0
Outcome
taproot diametere0
Direction
decreasee0

Not reportedTaxonComparator

Verbatim

e0

“At low P, the main responses were a decrease in taproot diameter, an increase in taproot dominance over its laterals and an increase in the inter-branch distance.”

✓ located verbatim in the source · abstract, characters 830–992 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Low P increased taproot dominance over laterals.

Treatment
low Pe0
Outcome
taproot dominance over its lateralse0
Direction
increasee0

Not reportedTaxonComparator

Verbatim

e0

“At low P, the main responses were a decrease in taproot diameter, an increase in taproot dominance over its laterals and an increase in the inter-branch distance.”

✓ located verbatim in the source · abstract, characters 830–992 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Low P increased inter-branch distance.

Treatment
low Pe0
Outcome
inter-branch distancee0
Direction
increasee0

Not reportedTaxonComparator

Verbatim

e0

“At low P, the main responses were a decrease in taproot diameter, an increase in taproot dominance over its laterals and an increase in the inter-branch distance.”

✓ located verbatim in the source · abstract, characters 830–992 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Genotype-by-P treatment effect was limited to root depth.

Material
genotypee0
Treatment
P treatmente0
Outcome
root depthe0

Not reportedTaxonDirection

Verbatim

e0

“Although the genotype x P treatment effect was limited to root depth, we identified a tradeoff between the capacity to maintain a thick taproot at low P and the dominance of the taproot over its laterals.”

✓ located verbatim in the source · abstract, characters 993–1197 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Taproot thickness maintenance traded off with taproot dominance.

Organ / stage
thick taproote0
Treatment
low Pe0
Outcome
dominance of the taproot over its lateralse0

Not reportedTaxonDirection

Verbatim

e0

“we identified a tradeoff between the capacity to maintain a thick taproot at low P and the dominance of the taproot over its laterals.”

✓ located verbatim in the source · abstract, characters 1063–1197 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

PUE varied among lettuce genotypes at both P levels.

Taxon
lettuceLactuca sativae0
Material
genotypese0
Outcome
phosphorus-use-efficiency (PUE)e0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“Regardless of the P level, the phosphorus-use-efficiency (PUE) varied among lettuce genotypes and was significantly correlated with total root biomass regardless of the P level.”

✓ located verbatim in the source · abstract, characters 1198–1375 · show in text ↑
Associationobservedoriginal resultsignificant (as stated)measured

Claim · model-written summary

PUE was significantly correlated with total root biomass.

Taxon
lettuceLactuca sativae0
Organ / stage
total root biomasse0
Outcome
phosphorus-use-efficiency (PUE)e0

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“Regardless of the P level, the phosphorus-use-efficiency (PUE) varied among lettuce genotypes and was significantly correlated with total root biomass regardless of the P level.”

✓ located verbatim in the source · abstract, characters 1198–1375 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Taproot depth and maximal apical diameter were the principal determinants of total root biomass.

Organ / stage
taproot depth and maximum apical diametere0
Outcome
total root biomasse0

Not reportedTaxonDirection

Verbatim

e0

“As taproot depth and maximum apical diameter were the principal determinants of total root biomass”

✓ located verbatim in the source · abstract, characters 1376–1474 · show in text ↑
Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

At low P, relative PUE increased in genotypes with thick or maintained apical diameter.

Material
genotypese0
Treatment
low Pe0
Outcome
PUEe0
Direction
increasee0
Qualifier
thickest apical diameters and/or those whose maximal apical diameter was not severely decreasede0

Not reportedTaxon

Verbatim

e0

“the relative increase in PUE at low P was observed in genotypes that showed the thickest apical diameters and/or those whose maximal apical diameter was not severely decreased at low P availability.”

✓ located verbatim in the source · abstract, characters 1476–1674 · show in text ↑

phosphorus · growth · Lactuca sativa (garden lettuce)Positive and negative results

14 papers: 8 positive, 6 negative or no effect

5 papers in the same direction as this paper · 8 in the opposite direction

  1. positive
  2. positive
  3. positive

10 papers more in this group

See all 14 papers →

Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.