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Reference Detail
| Reference | ||
|---|---|---|
| Author | Chen L. | |
| Title | Rac/Rop Small GTPases in Rice Innate Immunity | |
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Abstract: Plant-specific Rac/Rop small GTPases function as molecular switches for numerous signal transduction events, including defense responses. To understand the function of each of the seven Rac/Rop family members in rice, we studied the subcellular localization of Rac/Rop using GFP fusion proteins in transient expression systems. We also investigated the roles of these genes in disease resistance by testing single Rac/Rop-RNAi plants against the rice blast pathogen Magnaporthe grisea. Our studies revealed a strong correlation between the number of lysine/arginine (KR) residues in the polybasic region of Rac/Rop GTPases and their subcellular distribution in vivo. Infection assays showed that OsRac1 is a positive regulator of blast resistance, confirming previous observations, whereas OsRac4 and OsRac5 are negative regulators of blast resistance. OsRac6 may make minor contributions to disease resistance, while OsRac3 and OsRac7 are probably not involved in defense. Therefore, our study suggests that the rice Rac/Rop family plays multiple roles in diverse cellular activities and has both positive and negative functions in disease resistance. Recognition of pathogen-associated molecular patterns (PAMP) by pattern recognition receptors (PRRs) represents a critical first step of innate defense in plants and animals. However, maturation and transport of PRRs is not well understood. To extend our previous study, we studied the function of a novel OsRac1 interactor Hop/Sti1 and found that co-chaperone Hop/Sti1 was required for chitin-triggered immunity and resistance to rice blast fungus. Further, Hop/Sti1 interacts with Hsp90 and both bind the rice chitin receptor OsCERK1 in the endoplasmic reticulum (ER). Hop/Sti1 and Hsp90 are required for efficient transport of OsCERK1 from the ER to the plasma membrane (PM) via a pathway dependent on Sar1, a small GTPase which regulates ER-to-Golgi trafficking. Finally, Hop/Sti1 and Hsp90 are present at the PM in a complex (designated the ‘defensome’) with OsRac1, a plant specific Rho-type GTPase. Our results suggest that the Hop/Sti1-Hsp90 chaperone complex plays an important and likely conserved role in the maturation and transport of PRRs and may function to link PRRs and Rac/Rop GTPases. |
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| Journal | Thesis | |
| Country | Japan | |
| Volume | ||
| Pages | ||
| Year | 2010 | |
| PubMed ID | - | |
| PubMed Central ID | - | |
| DOI | - | |
| URL | - | |
| Relation | ||
| Gene | CERK1 FLS2 PAL1 PR10A RAC1 RAC3 RAC4 RAC5 RAC6 RAC7 SG2 STI1A STI1B | |
| INSD | - | |
| Strain | Wild Core Collection | - |
| Induced Mutation Lines(NIG Collection) | - | |
| Sterile Seed Strain | - | |
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Lethal Embryo Mutantion Strain |
- | |
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Stages in Each Organ - Muant Lines (Gene) |
- | |
| Cultivated Varieties(NIG Collection) | - | |
| Stages in Each Organ | - | |
