Meloidogyne incognita - rice (Oryza sativa) interaction: a new model system to study plant-root-knot nematode interactions in monocotyledons
Background Plant-parasitic nematodes developed strategies to invade and colonize their host plants, including expression of immune suppressors to overcome host defenses. Meloidogyne graminicola and M. incognita are root-knot nematode (RKN) species reported to damage rice ( Oryza sativa L.) cultivate...
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Published in | Rice (New York, N.Y.) Vol. 7; no. 1; p. 23 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
New York
Springer New York
22.09.2014
BioMed Central Ltd Springer Open |
Subjects | |
Online Access | Get full text |
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Summary: | Background
Plant-parasitic nematodes developed strategies to invade and colonize their host plants, including expression of immune suppressors to overcome host defenses.
Meloidogyne graminicola
and
M. incognita
are root-knot nematode (RKN) species reported to damage rice (
Oryza sativa
L.) cultivated in upland and irrigated systems. Despite
M. incognita
wide host range, study of the molecular plant - RKN interaction has been so far limited to a few dicotyledonous model plants. The aim of this study was to investigate if the rice cv. Nipponbare widely used in rice genomic studies could be used as a suitable monocotyledon host plant for studying
M. incognita
pathogenicity mechanisms. Here we compared the ability of
M. graminicola
and
M. incognita
to develop and reproduce in Nipponbare roots. Next, we tested if RKNs modulates rice immunity-related genes expression in galls during infection and express the
Mi-crt
gene encoding an immune suppressor.
Results
Root galling, mature females, eggs and newly formed J2s nematodes were obtained for both species in rice cultivated in hydroponic culture system after 4-5 weeks.
Meloidogyne graminicola
reproduced at higher rates than
M. incognita
on Nipponbare and the timing of infection was shorter. In contrast, the infection characteristics compared by histological analysis were similar for both nematode species. Giant cells formed from 2 days after infection (DAI) with
M. graminicola
and from 6 DAI with
M. incognita
. Real-time PCR (qRT-PCR) data indicated that RKNs are able to suppress transcription of immune regulators genes, such as
OsEDS1
,
OsPAD4
and
OsWRKY13
in young galls. Four
M. incognita
reference genes (
Mi-eif-3
,
Mi-GDP-2
,
Mi-Y45F10D.4
, and
Mi-actin
) were selected for normalizing nematode gene expression studies
in planta
and in pre-parasitic J2s.
Meloidogyne incognita
expressed the immune suppressor calreticulin gene (
Mi-crt
) in rice roots all along its infection cycle.
Conclusion
RKNs repress the transcription of key immune regulators in rice, likely in order to lower basal defence in newly-formed galls. The calreticulin Mi-CRT can be one of the immune-modulator effectors secreted by
M. incognita
in rice root tissues. Together, these data show that rice is a well suited model system to study host-
M. incognita
molecular interactions in monocotyledons. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1939-8425 1939-8433 1939-8433 |
DOI: | 10.1186/s12284-014-0023-4 |