Arabidopsis ALA1 and ALA2 Mediate RNAi-Based Antiviral Immunity

Zhu, Biyun; Gao, Hua; Xu, Gang; Wu, Dewei; Song, Susheng; Jiang, Hongshan; Zhu, Shuifang; Qi, Tiancong; Xie, Daoxin

doi:10.3389/fpls.2017.00422

Cited by 29 publications

(18 citation statements)

References 42 publications

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“…EMS mutagenesis in Col-0 background was performed as described previously 47 . Briefly, about 50,000 M1 seeds of Col-0 plants were incubated with 100 mM phosphate buffer (pH 7.5) 4 °C for 12 h, followed by mutagenized with 0.6% ethyl methanesulfonate (EMS) in phosphate buffer at 25 °C for 8 h. The M1 seeds were washed with sterilized water for 20 times and were grown in soil to generate the M2 population.…”

Section: Methodsmentioning

confidence: 99%

Genetic analysis of a Piezo-like protein suppressing systemic movement of plant viruses in Arabidopsis thaliana

Zhang

Tong

Liu

et al. 2019

Sci Rep

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As obligate intracellular phytopathogens, plant viruses must take advantage of hosts plasmodesmata and phloem vasculature for their local and long-distance transports to establish systemic infection in plants. In contrast to well-studied virus local transports, molecular mechanisms and related host genes governing virus systemic trafficking are far from being understood. Here, we performed a forward genetic screening to identify Arabidopsis thaliana mutants with enhanced susceptibility to a 2b-deleted mutant of cucumber mosaic virus (CMV-2aT∆2b). We found that an uncharacterized Piezo protein (AtPiezo), an ortholog of animal Piezo proteins with mechanosensitive (MS) cation channel activities, was required for inhibiting systemic infection of CMV-2aT∆2b and turnip mosaic virus tagged a green fluorescent protein (GFP) (TuMV-GFP). AtPiezo is induced by virus infection, especially in the petioles of rosette leaves. Thus, we for the first time demonstrate the biological function of Piezo proteins in plants, which might represent a common antiviral strategy because many monocot and dicot plant species have a single Piezo ortholog.

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Section: Methodsmentioning

confidence: 99%

Genetic analysis of a Piezo-like protein suppressing systemic movement of plant viruses in Arabidopsis thaliana

Zhang

Tong

Liu

et al. 2019

Sci Rep

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“…Notably, ALA1 and ALA2 are required for the biogenesis of the virus-activated siRNAs (vasi-RNAs), a recently described class of RDR1-dependent endogenous siRNAs that are induced by CMV and Turnip mosaic virus (TuMV) to target diverse host genes for silencing by a DCL4-AGO2 pathway (Cao et al, 2014). Interestingly, ALA1 has also been identified independently by screening for enhancers of rdr6 via infection with CMV-2aTD2b (Zhu et al, 2017).…”

mentioning

confidence: 99%

Identification of a New Host Factor Required for Antiviral RNAi and Amplification of Viral siRNAs

Guo

Wang

et al. 2017

Plant Physiol.

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Small interfering RNAs (siRNAs) are processed from virus-specific dsRNA to direct antiviral RNA interference (RNAi) in diverse eukaryotic hosts. We have recently performed a sensitized genetic screen in Arabidopsis () and identified two related phospholipid flippases required for antiviral RNAi and the amplification of virus-derived siRNAs by plant RNA-dependent RNA polymerase1 (RDR1) and RDR6. Here we report the identification and cloning of - () from the same genetic screen. encodes a multispan transmembrane protein broadly conserved in plants and animals with two homologous human proteins known as magnesium transporters. We show that mutant plants display no developmental defects and develop severe disease symptoms after infection with a mutant (CMV) defective in RNAi suppression. is induced by CMV infection, particularly in veins, and is required for antiviral RNAi and RDR6-dependent biogenesis of viral siRNAs. AVI2 is also necessary for Dicer-like2-mediated amplification of 22-nucleotide viral siRNAs induced in mutant plants by infection, but dispensable for RDR6-dependent biogenesis of endogenous transacting siRNAs. Further genetic studies illustrate that AVI2 plays a partially redundant role with AVI2H, the most closely related member in the gene family, in RDR1-dependent biogenesis of viral siRNAs and the endogenous virus-activated siRNAs (vasi-RNAs). Interestingly, we discovered a specific genetic interaction of AVI2 with AVI1 flippase that is critical for plant development. We propose that AVI1 and AVI2 participate in the virus-induced formation of the RDR1/RDR6-specific, membrane-bound RNA synthesis compartment, essential for the biogenesis of highly abundant viral siRNAs and vasi-RNAs.

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“…To date, our observation of a 6.5-fold reduction in ala4/5 rosette diameter (Fig. 2b) is the most severe growth defect associated with a plant flippase deficiency, in comparison to a ~1.2-fold reduction for an ala3 KO (McDowell et al, 2013), a ~2.5-fold reduction for ALA1 RNAi lines grown at 8-12°C (Gomès et al, 2000), and no significant changes reported for an ala2 KO (Zhu et al, 2017), an ala6/7 KO (McDowell et al, 2015), or an ala10 KO (Poulsen et al, 2015;Botella et al, 2016). The loss of ALA4/5 also resulted in cell size reductions across multiple cell types, including leaf epidermal cells which showed a 2.7-fold reduction in surface area (Fig.…”

Section: Ala4/5 Are Flippases That Transport Pc Sm Pe and Psmentioning

confidence: 66%

The Lipid Flippases ALA4 and ALA5 Play Critical Roles in Cell Expansion and Plant Growth

et al. 2020

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A subclass of lipid flippases contribute to glycerolipid and sphingolipid homeostasis in Arabidopsis leaves, and play critical roles in cell expansion and vegetative growth. Footnotes: Author contributions: J.D. authored the manuscript. R.P. and J.D. analyzed vegetative physiology. S.M. bred the double-knockout lines and identified dwarf mutants. E.B., A.R., and J.S. performed subcellular localization experiments. L.P. and R.L. were involved in the cloning of ALA5 for yeast expression. T.B. performed lipid uptake and functional complementation assays. R.L. analyzed the data and carried out statistical analysis for yeast experiments. M.P. and R.L. supervised yeast experiments. E.C. and R.C. performed sphingolipid profiling of ala4/5 mutants. J.H. performed all plant crosses, supervised in planta experiments, and assisted J.D. in writing. J.H. agrees to serve as author responsible for contact.

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Arabidopsis ALA1 and ALA2 Mediate RNAi-Based Antiviral Immunity

Cited by 29 publications

References 42 publications

Genetic analysis of a Piezo-like protein suppressing systemic movement of plant viruses in Arabidopsis thaliana

Genetic analysis of a Piezo-like protein suppressing systemic movement of plant viruses in Arabidopsis thaliana

Identification of a New Host Factor Required for Antiviral RNAi and Amplification of Viral siRNAs

The Lipid Flippases ALA4 and ALA5 Play Critical Roles in Cell Expansion and Plant Growth

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