Abstract
Abstract This study explored the establishment and optimization of Ri (root inducing) technology for apple breeding, using the bacterium Rhizobium rhizogenes to obtain Ri lines with compact shoots and stronger root systems. The transformation and shoot regeneration for Malus domestica cultivars was studied in detail. Various R. rhizogenes strains, scion and rootstock genotypes, explant types, wounding methods and explant orientations were tested for hairy root induction. Most of the 16 tested strains, especially those with plasmid type III, induced hairy roots in the rootstock genotype ‘M26’. Although apple genotypes differed in response, in most of them roots were successfully induced using strains ATCC 15834, LMG 63 and LMG 150, with leaf blades outperforming petioles as explants. Wounding by scratching or sonication further improved transformation efficiency, as did placing leaf blades with their abaxial side upward on root induction medium. The majority (94%) of roots formed in one transformation experiment were tested PCR-positive for at least one T-DNA gene. Shoot regeneration experiments investigated salt concentrations, gelling agents, cytokinin types, concentrations, and a resting period on hormone-free medium. Shoot regeneration was highly genotype-dependent varying between 0 and 83%, whereas only minor, non-significant effects were observed for the treatments tested. Copy numbers of T-DNA genes were estimated using digital PCR for the first time in apple Ri lines. In the greenhouse, two Ri lines showed compact shoots and shorter leaves, but no enhanced root system. The improved protocol provides a valuable tool for breeders and scientists to obtain and further use Ri lines.
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Claims 14
Claim · model-written summary
Most tested R. rhizogenes strains induced hairy roots in M26, especially plasmid type III strains.
- Taxon
- Malus domestica
Malus domesticat0 - Material
- ‘M26’e0
- Treatment
- strainse0
- Interactor
- Rhizobium rhizogenes
Martinezella rhizogenest0other - Outcome
- hairy rootse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Most of the 16 tested strains, especially those with plasmid type III, induced hairy roots in the rootstock genotype ‘M26’.”
t0“Rhizobium rhizogenes-mediated transformation, regeneration and characterization of Malus domestica”
Claim · model-written summary
ATCC 15834 induced roots in most apple genotypes.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- ATCC 15834e0
- Interactor
- Rhizobium rhizogenesMartinezella rhizogenest0other
- Outcome
- rootse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in most of them roots were successfully induced using strains ATCC 15834, LMG 63 and LMG 150”
t0“Rhizobium rhizogenes-mediated transformation, regeneration and characterization of Malus domestica”
Claim · model-written summary
LMG 63 induced roots in most apple genotypes.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- LMG 63e0
- Outcome
- rootse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in most of them roots were successfully induced using strains ATCC 15834, LMG 63 and LMG 150”
t0“Malus domestica”
Claim · model-written summary
LMG 150 induced roots in most apple genotypes.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- LMG 150e0
- Outcome
- rootse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in most of them roots were successfully induced using strains ATCC 15834, LMG 63 and LMG 150”
t0“Malus domestica”
Claim · model-written summary
Leaf blades outperformed petioles for root induction.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- leaf bladese0
- Outcome
- root inductione1
- Direction
- outperforminge0
- Comparator
- petiolese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf blades outperforming petioles as explants”
t0“Malus domestica”
e1“roots were successfully induced using strains ATCC 15834, LMG 63 and LMG 150, with leaf blades outperforming petioles as explants. Wounding by scratching or sonication further improved transformation efficiency, as did placing leaf blades with their abaxial side upward on root induction medium”
Claim · model-written summary
Scratching improved transformation efficiency.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- scratchinge0
- Outcome
- transformation efficiencye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wounding by scratching or sonication further improved transformation efficiency”
t0“Malus domestica”
Claim · model-written summary
Sonication improved transformation efficiency.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- sonicatione0
- Outcome
- transformation efficiencye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wounding by scratching or sonication further improved transformation efficiency”
t0“Malus domestica”
Claim · model-written summary
Abaxial-side-up leaf placement improved transformation efficiency.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- placing leaf blades with their abaxial side upwarde0
- Outcome
- transformation efficiencye1
- Direction
- improvede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“placing leaf blades with their abaxial side upward on root induction medium”
t0“Malus domestica”
e1“Wounding by scratching or sonication further improved transformation efficiency, as did placing leaf blades with their abaxial side upward on root induction medium”
Claim · model-written summary
Most formed roots tested positive for a T-DNA gene.
- Taxon
- Malus domesticaMalus domesticat0
- Organ / stage
- rootse0
- Outcome
- PCR-positive for at least one T-DNA genee0
- Value
- 94%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The majority (94%) of roots formed in one transformation experiment were tested PCR-positive for at least one T-DNA gene.”
t0“Malus domestica”
Claim · model-written summary
Apple shoot regeneration varied by genotype from 0 to 83%.
- Taxon
- Malus domesticaMalus domesticat0
- Material
- genotypee0
- Outcome
- Shoot regeneratione0
- Value
- 0 and 83%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shoot regeneration was highly genotype-dependent varying between 0 and 83%”
t0“Malus domestica”
Claim · model-written summary
Tested shoot-regeneration treatments had only minor nonsignificant effects.
- Taxon
- Malus domesticaMalus domesticat0
- Treatment
- treatments testede0
- Outcome
- Shoot regeneratione1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“only minor, non-significant effects were observed for the treatments tested”
t0“Malus domestica”
e1“Shoot regeneration was highly genotype-dependent varying between 0 and 83%, whereas only minor, non-significant effects were observed for the treatments tested”
Claim · model-written summary
Digital PCR estimated T-DNA gene copy numbers in apple Ri lines for the first time.
- Taxon
- appleMalus domesticae0
- Outcome
- Copy numbers of T-DNA genese0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Copy numbers of T-DNA genes were estimated using digital PCR for the first time in apple Ri lines.”
Claim · model-written summary
Two Ri lines had compact shoots and shorter leaves in a greenhouse.
- Taxon
- Malus domesticaMalus domesticat0
- Material
- Ri linese0
- Outcome
- compact shoots and shorter leavese0
- Setting
- greenhousee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the greenhouse, two Ri lines showed compact shoots and shorter leaves”
t0“Malus domestica”
Claim · model-written summary
Two Ri lines showed no enhanced root system.
- Taxon
- Malus domesticaMalus domesticat0
- Outcome
- root systeme0
- Direction
- no enhancede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but no enhanced root system”
t0“Malus domestica”