Abstract
The immune response in plants is regulated by several phytohormones and involves the overexpression of defense genes, including the pathogenesis-related (PR-) genes. The data reported in this paper indicate that nematodes can suppress the immune response by inhibiting the expression of defense genes. Transcripts from nine defense genes were detected by qRT-PCR in the roots of tomato plants at three and seven days post-inoculation (dpi) with living juveniles (J2s) of Meloidogyne incognita (root-knot nematodes, RKNs). All the salicylic acid (SA)-responsive genes tested (PR-1, PR-2, PR-4b, PR-5) were down-regulated in response to nematode infection. On the contrary, the expression of jasmonic acid (JA)-responsive genes, including ACO (encoding the enzyme 1-aminocyclopropane-1-carboxylic acid oxidase, which catalyzes the last step of ethylene (ET) biosynthesis) and JERF3 (Jasmonate Ethylene Response Factor 3), was unaffected by the infection. Conversely, the effect of nematode attack on the activities of the defense enzymes endoglucanase and endochitinase, encoded by PR-2 and PR-3, respectively, changed depending on the tested dpi. At 5 dpi, both enzymes were inhibited in inoculated plants compared to healthy controls. The genes encoding glutathione peroxidase (GPX) and catalase (CAT), both part of the antioxidant plant system, were highly overexpressed. Additionally, the activity of the antioxidant enzymes superoxide dismutase (SOD), CAT, and ascorbate peroxidase (APX) was enhanced in infected roots. Isoelectrofocusing of root extracts revealed novel SOD isoforms in samples from inoculated plants. Furthermore, plants were pre-treated with an array of key compounds, including hormone generators, inhibitors of SA or JA-mediated defense pathways, reactive oxygen species (ROS) scavengers and generators, inhibitors of ROS generation, and compounds that interfere with calcium-mediated metabolism. After treatments, plants were inoculated with RKNs, and nematodes were allowed to complete their life cycle. Factors of plant growth and infection level in treated plants were compared with those from untreated inoculated plants. Generally, compounds that decreased SA and/or ROS levels increased infection severity, while those that reduced JA/ET levels did not affect infection rates. ROS generators induced resistance against the pests. Compounds that silence calcium signaling by preventing its intake augmented infection symptoms. The data shown in this paper indicate that SA-mediated plant immune responses are consistently suppressed during the early stages of nematode infection, and this restriction is associated with the activation of the antioxidant ROS-scavenging system.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 10
Claim · model-written summary
Nematode infection down-regulated all tested salicylic-acid-responsive PR genes in tomato roots.
- Taxon
- Tomato
Solanum lycopersicumt0 - Treatment
- nematode infectione0
- Interactor
- Meloidogyne incognita
_penetrates_a_tomato_root_-_USDA-ARS.jpg?width=60)
Meloidogyne incognitae1pathogen - Gene
- PR-1, PR-2, PR-4b, PR-5e0
- Outcome
- salicylic acid (SA)-responsive genese0
- Direction
- down-regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_penetrates_a_tomato_root_-_USDA-ARS.jpg?width=500)
Verbatim
t0“Tomato”
e0“All the salicylic acid (SA)-responsive genes tested (PR-1, PR-2, PR-4b, PR-5) were down-regulated in response to nematode infection.”
e1“Meloidogyne incognita (root-knot nematodes, RKNs)”
Claim · model-written summary
Nematode infection left tomato ACO and JERF3 gene expression unaffected.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- infectione0
- Gene
- ACOe0
- Outcome
- expression of jasmonic acid (JA)-responsive genese0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“the expression of jasmonic acid (JA)-responsive genes, including ACO (encoding the enzyme 1-aminocyclopropane-1-carboxylic acid oxidase, which catalyzes the last step of ethylene (ET) biosynthesis) and JERF3 (Jasmonate Ethylene Response Factor 3), was unaffected by the infection.”
Claim · model-written summary
At five days after inoculation, nematodes inhibited tomato root endoglucanase and endochitinase activities relative to healthy controls.
- Taxon
- TomatoSolanum lycopersicumt0
- Organ / stage
- 5 dpie0
- Treatment
- inoculated plantse0
- Outcome
- activities of the defense enzymes endoglucanase and endochitinasee1
- Direction
- inhibitede0
- Comparator
- healthy controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“At 5 dpi, both enzymes were inhibited in inoculated plants compared to healthy controls.”
e1“activities of the defense enzymes endoglucanase and endochitinase”
Claim · model-written summary
Antioxidant GPX and CAT genes were highly overexpressed in infected tomato roots.
- Taxon
- TomatoSolanum lycopersicumt0
- Gene
- GPXe0
- Outcome
- genes encoding glutathione peroxidase (GPX) and catalase (CAT)e0
- Direction
- highly overexpressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“The genes encoding glutathione peroxidase (GPX) and catalase (CAT), both part of the antioxidant plant system, were highly overexpressed.”
Claim · model-written summary
Antioxidant SOD, CAT and APX activities were enhanced in infected tomato roots.
- Taxon
- TomatoSolanum lycopersicumt0
- Organ / stage
- infected rootse0
- Outcome
- activity of the antioxidant enzymes superoxide dismutase (SOD), CAT, and ascorbate peroxidase (APX)e0
- Direction
- enhancede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“the activity of the antioxidant enzymes superoxide dismutase (SOD), CAT, and ascorbate peroxidase (APX) was enhanced in infected roots.”
Claim · model-written summary
Inoculated tomato roots showed novel SOD isoforms.
- Taxon
- TomatoSolanum lycopersicumt0
- Organ / stage
- root extractse0
- Gene
- SODe0
- Outcome
- novel SOD isoformse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“Isoelectrofocusing of root extracts revealed novel SOD isoforms in samples from inoculated plants.”
Claim · model-written summary
Treatments that decreased salicylic acid or ROS increased nematode infection severity in tomato.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- compounds that decreased SA and/or ROS levelse0
- Outcome
- infection severitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“compounds that decreased SA and/or ROS levels increased infection severity”
Claim · model-written summary
Treatments that reduced JA or ET did not affect nematode infection rates in tomato.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- those that reduced JA/ET levelse0
- Outcome
- infection ratese0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“those that reduced JA/ET levels did not affect infection rates.”
Claim · model-written summary
ROS generators induced tomato resistance to root-knot nematodes.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- ROS generatorse0
- Outcome
- resistance against the pestse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“ROS generators induced resistance against the pests.”
Claim · model-written summary
Compounds that silence calcium signaling increased nematode infection symptoms in tomato.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Compounds that silence calcium signaling by preventing its intakee0
- Outcome
- infection symptomse0
- Direction
- augmentede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tomato”
e0“Compounds that silence calcium signaling by preventing its intake augmented infection symptoms.”
The same questions in other papers
calcium atom · disease · Solanum lycopersicum (tomato)Results differ
14 papers in the same direction as this paper · 35 in the opposite direction
- positive
- positive
- positive
46 papers more in this group
See all 50 papers →ethene · disease · Solanum lycopersicum (tomato)Positive and negative results
3 papers in the same direction as this paper · 5 in the opposite direction
- positive
- positive
- positive
5 papers more in this group
See all 9 papers →jasmonic acid · disease · Solanum lycopersicum (tomato)Positive and negative results
4 papers in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
5 papers more in this group
See all 9 papers →salicylic acid · disease · Solanum lycopersicum (tomato)Positive and negative results
3 papers in the same direction as this paper · 35 in the opposite direction
- positive
- positive
- positive
35 papers more in this group
See all 39 papers →infection · Meloidogyne incognita · Solanum lycopersicum (tomato)Positive and negative results
9 papers in the same direction as this paper · 9 in the opposite direction
- positive
- positive
- positive
15 papers more in this group
See all 19 papers →infection · molecular: expression · Solanum lycopersicum (tomato)Positive and negative results
11 papers in the same direction as this paper · 26 in the opposite direction
- negative
- positive
- positive
34 papers more in this group
See all 38 papers →inoculation · physiology: antioxidant enzymes · Solanum lycopersicum (tomato)Positive and negative results
2 papers in the same direction as this paper · 51 in the opposite direction
- positive
- positive
- positive
50 papers more in this group
See all 54 papers →loss of function · disease · Solanum lycopersicum (tomato)Positive and negative results
91 papers in the same direction as this paper · 63 in the opposite direction
- no effect
- positive
- positive
151 papers more in this group
See all 155 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.