Abstract
Serratia proteamaculans 1-102 (1-102) promotes soybean-bradyrhizobia nodulation and growth, but the mechanism is unknown. After adding isoflavonoid inducers to 1-102 culture, an active peak with a retention time of about 105 min in the HPLC fractionation was isolated using a bioassay based on the stimulation of soybean seed germination. The plant growth-promoting activity of this material was compared with 1-102 culture (cells) and supernatant under greenhouse conditions. The activator was applied to roots in 83, 830 and 8300 HPLC microvolts (microV) per seedling when plants were inoculated with bradyrhizobia or sprayed onto the leaves in same concentrations at 20 d after inoculation. The root-applied activator, especially at 1 ml of 830 microV per seedling, enhanced soybean nodulation and growth at the same level as 1-102 culture under both optimal and sub-optimal root zone temperatures. Thus, this activator stimulating soybean seed germination is also responsible for the plant growth-promoting activity of 1-102 culture. However, when sprayed onto the leaves, the activator did not increase growth and in higher concentrations decreased average single leaf area. The results suggest that this inducible activator might be a lipo-chitooligosaccharide (LCO) analogue. LCOs act as rhizobia-to-legume signals stimulating root nodule formation. The activator could provide additional 'signal', increasing in the signal quality (the signal-to-noise ratio, SNR) of the plant-rhizobia signal exchange process.
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Claims 6
Claim · model-written summary
An isolated activator stimulated soybean seed germination.
- Taxon
- soybean
Glycine maxe0 - Outcome
- stimulation of soybean seed germinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an active peak with a retention time of about 105 min in the HPLC fractionation was isolated using a bioassay based on the stimulation of soybean seed germination”
Claim · model-written summary
Root-applied activator enhanced soybean nodulation and growth to the level of 1-102 culture at optimal and suboptimal root-zone temperatures.
- Taxon
- soybeanGlycine maxe0
- Treatment
- root-applied activatore0
- Outcome
- soybean nodulation and growthe0
- Direction
- enhancede0
- Value
- 1 ml of 830 microV per seedlinge0
- Qualifier
- under both optimal and sub-optimal root zone temperaturese0
- Comparator
- 1-102 culturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The root-applied activator, especially at 1 ml of 830 microV per seedling, enhanced soybean nodulation and growth at the same level as 1-102 culture under both optimal and sub-optimal root zone temperatures.”
Claim · model-written summary
Foliar activator did not increase growth.
- Taxon
- soybeanGlycine maxt0
- Treatment
- sprayed onto the leavese0
- Outcome
- growthe0
- Direction
- did not increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when sprayed onto the leaves, the activator did not increase growth”
t0“soybean”
Claim · model-written summary
Higher foliar activator concentrations decreased average single-leaf area.
- Taxon
- soybeanGlycine maxt0
- Treatment
- activatore1
- Outcome
- average single leaf areae0
- Direction
- decreasede0
- Qualifier
- in higher concentrationse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in higher concentrations decreased average single leaf area”
e1“The root-applied activator, especially at 1 ml of 830 microV per seedling, enhanced soybean nodulation and growth at the same level as 1-102 culture under both optimal and sub-optimal root zone temperatures.”
t0“soybean”
Claim · model-written summary
The activator might be a lipo-chitooligosaccharide analogue.
- Taxon
- soybeanGlycine maxt0
- Outcome
- lipo-chitooligosaccharide (LCO) analoguee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this inducible activator might be a lipo-chitooligosaccharide (LCO) analogue”
t0“soybean”
Claim · model-written summary
The activator may add signal to soybean-rhizobia exchange.
- Taxon
- soybeanGlycine maxt0
- Outcome
- signal qualitye0
- Direction
- increasinge0
- Qualifier
- additional 'signal'e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activator could provide additional 'signal', increasing in the signal quality (the signal-to-noise ratio, SNR) of the plant-rhizobia signal exchange process.”
t0“soybean”
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See all 207 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.