Paper · 2022 · Frontiers in Plant Science

Defeating Huanglongbing Pathogen Candidatus Liberibacter asiaticus With Indigenous Citrus Endophyte Bacillus subtilis L1-21

Shahzad Munir; Yongmei Li; Pengbo He; et al.

5
claims
10
verbatim quotes
23
citations
4
research areas
✓
Open access · cc-by

Abstract

Huanglongbing (HLB) has turned into a devastating botanical pandemic of citrus crops, caused by Candidatus Liberibacter asiaticus ( C Las). However, until now the disease has remained incurable with very limited control strategies available. Restoration of the affected microbiomes in the diseased host through the introduction of an indigenous endophyte Bacillus subtilis L1-21 isolated from healthy citrus may provide an innovative approach for disease management. A novel half-leaf method was developed in vitro to test the efficacy of the endophyte L1-21 against C Las. Application of B. subtilis L1-21 at 10 4 colony forming unit (cfu ml −1 ) resulted in a 1,000-fold reduction in the C Las copies per gram of leaf midrib (10 7 to 10 4 ) in 4 days. In HLB-affected citrus orchards over a period of 2 years, the C Las incidence was reduced to < 3%, and C Las copies declined from 10 9 to 10 4 g −1 of diseased leaf midribs in the endophyte L1-21 treated trees. Reduction in disease incidence may corroborate a direct or an indirect biocontrol effect of the endophytes as red fluorescent protein-labeled B. subtilis L1-21 colonized and shared niche (phloem) with C Las. This is the first large-scale study for establishing a sustainable HLB control strategy through citrus endophytic microbiome restructuring using an indigenous endophyte.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗

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Claims 5

Method / resourceobservedoriginal resultmeasured

Claim · model-written summary

A half-leaf method was developed to test L1-21 against C Las.

Taxon
citrusCitrust0
Interactor
C Lase0pathogen
Outcome
half-leaf methode0

Not reportedComparatorValue

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

Citrus
Citrus · Taxon · picture of the genus (one of its species)Ellen Levy Finch ( Elf ) · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“A novel half-leaf method was developed in vitro to test the efficacy of the endophyte L1-21 against C Las.”

✓ located verbatim in the source · abstract, characters 467–573 · show in text ↑
t0

“Citrus”

✓ located verbatim in the source · title, characters 83–89 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

B. subtilis L1-21 reduced C Las copies in citrus leaf midribs 1,000-fold in four days.

Taxon
citrusCitrust0
Treatment
Application of B. subtilis L1-21 at 10 4 colony forming unit (cfu ml −1 )e0
Interactor
C Lase0pathogen
Second interactor
B. subtilis L1-21Bacillus subtilise0biocontrol_agent
Outcome
C Las copies per gram of leaf midribe0
Direction
reductione0
Value
1,000-folde0

Not reportedComparator

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

Citrus
Citrus · Taxon · picture of the genus (one of its species)Ellen Levy Finch ( Elf ) · CC BY-SA 3.0 · Wikimedia Commons ↗
Bacillus subtilis
Bacillus subtilis · Second interactorY tambe (original uploader) · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“Application of B. subtilis L1-21 at 10 4 colony forming unit (cfu ml −1 ) resulted in a 1,000-fold reduction in the C Las copies per gram of leaf midrib (10 7 to 10 4 ) in 4 days.”

✓ located verbatim in the source · abstract, characters 574–753 · show in text ↑
t0

“Citrus”

✓ located verbatim in the source · title, characters 83–89 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

In treated citrus orchards C Las incidence fell below 3% over two years.

Taxon
citrusCitruse0
Treatment
endophyte L1-21 treated treese1
Interactor
C Lase0pathogen
Outcome
C Las incidencee0
Direction
reducede0
Value
< 3%e0

Not reportedComparator

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

Citrus
Citrus · Taxon · picture of the genus (one of its species)Ellen Levy Finch ( Elf ) · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“In HLB-affected citrus orchards over a period of 2 years, the C Las incidence was reduced to < 3%,”

✓ located verbatim in the source · abstract, characters 754–852 · show in text ↑
e1

“endophyte L1-21 treated trees”

✓ located verbatim in the source · abstract, characters 934–963 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

C Las copies in treated citrus midribs fell from 10 9 to 10 4 g −1.

Taxon
citrusCitrust0
Treatment
endophyte L1-21 treated treese0
Interactor
C Lase0pathogen
Outcome
C Las copiese0
Direction
declinede0
Value
10 9 to 10 4 g −1e0

Not reportedComparator

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

Citrus
Citrus · Taxon · picture of the genus (one of its species)Ellen Levy Finch ( Elf ) · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“C Las copies declined from 10 9 to 10 4 g −1 of diseased leaf midribs in the endophyte L1-21 treated trees.”

✓ located verbatim in the source · abstract, characters 857–964 · show in text ↑
t0

“Citrus”

✓ located verbatim in the source · title, characters 83–89 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

B. subtilis L1-21 colonized phloem shared with C Las.

Taxon
citrusCitrust0
Interactor
C Lase0pathogen
Second interactor
B. subtilis L1-21Bacillus subtilise0biocontrol_agent
Outcome
colonized and shared niche (phloem) with C Lase0

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

Citrus
Citrus · Taxon · picture of the genus (one of its species)Ellen Levy Finch ( Elf ) · CC BY-SA 3.0 · Wikimedia Commons ↗
Bacillus subtilis
Bacillus subtilis · Second interactorY tambe (original uploader) · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“red fluorescent protein-labeled B. subtilis L1-21 colonized and shared niche (phloem) with C Las.”

✓ located verbatim in the source · abstract, characters 1075–1172 · show in text ↑
t0

“Citrus”

✓ located verbatim in the source · title, characters 83–89 · show in text ↑

Bacillus subtilis · molecular: metabolites · CitrusResults agree

2 papers: 2 positive, 0 negative or no effect

1 paper in the same direction as this paper

  1. positive
See all 2 papers →

inoculation · molecular: metabolites · CitrusPositive and negative results

9 papers: 8 positive, 1 negative or no effect

7 papers in the same direction as this paper · 1 in the opposite direction

  1. positive
  2. positive
  3. no effect

5 papers more in this group

See all 9 papers →

inoculation · disease · CitrusPositive and negative results

23 papers: 11 positive, 12 negative or no effect

10 papers in the same direction as this paper · 12 in the opposite direction

  1. no effect
  2. negative
  3. negative

19 papers more in this group

See all 23 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.