The actin‐related protein 2/3 complex (Arp2/3 complex), a key regulator of actin cytoskeletal dynamics, has been linked to multiple cellular processes, including those associated with response to stress. Herein, the
Actin filament assembly in plants is a dynamic process, requiring the activity of more than 75 actin‐binding proteins. Central to the regulation of filament assembly and stability is the activity of a conserved family of actin‐depolymerizing factors (
- NSF-PAR ID:
- 10026983
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 89
- Issue:
- 6
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 1210-1224
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract gene, encoding a subunit protein of the Arp2/3 complex, was identified and characterized.Solanum habrochaites ARPC3ShARPC3 encodes a 174‐amino acid protein possessing a conserved P21‐Arc domain. Silencing ofShARPC3 resulted in enhanced susceptibility to the powdery mildew pathogen (Oidium neolycopersici On ‐Lz), demonstrating a role forShARPC3 in defence signalling. Interestingly, a loss ofShARPC3 coincided with enhanced susceptibility toOn ‐Lz, a process that we hypothesize is the result of a block in the activity of SA‐mediated defence signalling. Conversely, overexpression ofShARPC3 in , followed by inoculation withArabidopsis thaliana On ‐Lz, showed enhanced resistance, including the rapid induction of hypersensitive cell death and the generation of reactive oxygen. Heterologous expression ofShARPC3 in thearc18 mutant of (i.e.,Saccharomyces cerevisiae ∆arc18 ) resulted in complementation of stress‐induced phenotypes, including high‐temperature tolerance. Taken together, these data support a role for ShARPC3 in tomato through positive regulation of plant immunity in response toO .neolycopersici pathogenesis. -
Summary The GreenCut encompasses a suite of nucleus‐encoded proteins with orthologs among green lineage organisms (plants, green algae), but that are absent or poorly conserved in non‐photosynthetic/heterotrophic organisms. In
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Premise Light is critical in the ability of plants to accumulate chlorophyll. When exposed to far‐red (
FR ) light and then grown in white light in the absence of sucrose, wild‐type seedlings fail to green in a response known as theFR block of greening (BOG ). This response is controlled by phytochrome A through repression of protochlorophyllide reductase‐encoding (POR ) genes byFR light coupled with irreversible plastid damage. Sigma (SIG ) factors are nuclear‐encoded proteins that contribute to plant greening and plastid development through regulating gene transcription in chloroplasts and impacting retrograde signaling from the plastid to nucleus.SIG s are regulated by phytochromes, and the expression of someSIG factors is reduced in phytochrome mutant lines, includingphyA . Given the association of phyA with theFR BOG and its regulation ofSIG factors, we investigated the potential regulatory role ofSIG factors in theFR BOG response.Methods We examined
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sig mutants, only thesig6 mutant significantly accumulated chlorophyll afterFR BOG treatment, similar to thephyA mutant.SIG 6 appears to control protochlorophyllide accumulation by contributing to the regulation of tetrapyrrole biosynthesis associated with glutamyl‐tRNA reductase (HEMA 1) function, select phytochrome‐interacting factor genes (PIF4 andPIF6 ), andPENTA1 , which regulatesPORA mRNA translation afterFR exposure.Conclusions Regulation of
SIG6 plays a significant role in plant responses toFR exposure during theBOG response. -
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