Abstract
Legume plants are able to establish a symbiotic relationship with soil bacteria from the genus Rhizobium, leading to the formation of nitrogen-fixing root nodules. Successful nodulation requires both the formation of infection threads (ITs) in the root epidermis and the activation of cell division in the cortex to form the nodule primordium. This study describes the characterization of RabA2, a common bean (Phaseolus vulgaris) cDNA previously isolated as differentially expressed in root hairs infected with Rhizobium etli, which encodes a protein highly similar to small GTPases of the RabA2 subfamily. This gene is expressed in roots, particularly in root hairs, where the protein was found to be associated with vesicles that move along the cell. The role of this gene during nodulation has been studied in common bean transgenic roots using a reverse genetic approach. Examination of root morphology in RabA2 RNA interference (RNAi) plants revealed that the number and length of the root hairs were severely reduced in these plants. Upon inoculation with R. etli, nodulation was completely impaired and no induction of early nodulation genes (ENODs), such as ERN1, ENOD40, and Hap5, was detected in silenced hairy roots. Moreover, RabA2 RNAi plants failed to induce root hair deformation and to initiate ITs, indicating that morphological changes that precede bacterial infection are compromised in these plants. We propose that RabA2 acts in polar growth of root hairs and is required for reorientation of the root hair growth axis during bacterial infection.
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Claims 7
Claim · model-written summary
RabA2 is expressed in common bean roots, particularly root hairs.
- Taxon
- common bean
Phaseolus vulgarise1 - Organ / stage
- root hairse0
- Gene
- RabA2e1
- Outcome
- expressed in roots, particularly in root hairse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This gene is expressed in roots, particularly in root hairs”
e1“RabA2, a common bean (Phaseolus vulgaris) cDNA”
Claim · model-written summary
RabA2 protein was associated with moving vesicles in root hairs.
- Taxon
- common beanPhaseolus vulgarise1
- Gene
- RabA2e1
- Outcome
- associated with vesicles that move along the celle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“where the protein was found to be associated with vesicles that move along the cell”
e1“RabA2, a common bean (Phaseolus vulgaris) cDNA”
Claim · model-written summary
RabA2 RNA interference severely reduced common bean root hair number and length.
- Taxon
- common beanPhaseolus vulgarise1
- Treatment
- RabA2 RNA interference (RNAi)e0
- Gene
- RabA2e0
- Outcome
- number and length of the root hairse0
- Direction
- severely reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Examination of root morphology in RabA2 RNA interference (RNAi) plants revealed that the number and length of the root hairs were severely reduced in these plants.”
e1“RabA2, a common bean (Phaseolus vulgaris) cDNA”
Claim · model-written summary
RabA2 silencing completely impaired nodulation after R. etli inoculation.
- Taxon
- common beanPhaseolus vulgarise2
- Treatment
- RabA2 RNA interference (RNAi)e1
- Interactor
- R. etliRhizobium etlie0symbiont
- Outcome
- nodulatione0
- Direction
- completely impairede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upon inoculation with R. etli, nodulation was completely impaired”
e1“RabA2 RNA interference (RNAi) plants”
e2“RabA2, a common bean (Phaseolus vulgaris) cDNA”
Claim · model-written summary
Silenced roots showed no induction of ERN1, ENOD40 and Hap5 after R. etli inoculation.
- Taxon
- common beanPhaseolus vulgarise2
- Treatment
- RabA2 RNA interference (RNAi)e1
- Interactor
- R. etliRhizobium etlie0symbiont
- Outcome
- induction of early nodulation genes (ENODs), such as ERN1, ENOD40, and Hap5e0
- Direction
- no inductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upon inoculation with R. etli, nodulation was completely impaired and no induction of early nodulation genes (ENODs), such as ERN1, ENOD40, and Hap5, was detected in silenced hairy roots.”
e1“RabA2 RNA interference (RNAi) plants”
e2“RabA2, a common bean (Phaseolus vulgaris) cDNA”
Claim · model-written summary
RabA2 RNAi prevented root hair deformation and infection thread initiation.
- Taxon
- common beanPhaseolus vulgarise1
- Treatment
- RabA2 RNAie0
- Outcome
- root hair deformation and to initiate ITse0
- Direction
- failed to inducee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RabA2 RNAi plants failed to induce root hair deformation and to initiate ITs”
e1“RabA2, a common bean (Phaseolus vulgaris) cDNA”
Claim · model-written summary
The authors propose RabA2 acts in polar root hair growth and growth-axis reorientation during bacterial infection.
- Taxon
- common beanPhaseolus vulgarise1
- Gene
- RabA2e0
- Outcome
- polar growth of root hairs and is required for reorientation of the root hair growth axise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We propose that RabA2 acts in polar growth of root hairs and is required for reorientation of the root hair growth axis during bacterial infection.”
e1“RabA2, a common bean (Phaseolus vulgaris) cDNA”
The same questions in other papers
loss of function · Rhizobium etli · Phaseolus vulgaris (common bean)Positive and negative results
1 in the opposite direction
- positive
loss of function · growth · Phaseolus vulgaris (common bean)Results agree
2 papers in the same direction as this paper
- negative
- negative
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.