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Arabidopsis AtPLC2 Is a Primary Phosphoinositide-Specific Phospholipase C in Phosphoinositide Metabolism and the Endoplasmic Reticulum Stress Response.

Kanehara K, Yu CY, Cho Y, Cheong WF, Torta F, Shui G, Wenk MR, Nakamura Y - PLoS Genet. (2015)

Bottom Line: The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth.Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles.Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan; Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Graduate Institute of Biotechnology and Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan; Muroran Institute of Technology, Muroran, Japan.

ABSTRACT
Phosphoinositides represent important lipid signals in the plant development and stress response. However, multiple isoforms of the phosphoinositide biosynthetic genes hamper our understanding of the pivotal enzymes in each step of the pathway as well as their roles in plant growth and development. Here, we report that phosphoinositide-specific phospholipase C2 (AtPLC2) is the primary phospholipase in phosphoinositide metabolism and is involved in seedling growth and the endoplasmic reticulum (ER) stress responses in Arabidopsis thaliana. Lipidomic profiling of multiple plc mutants showed that the plc2-1 mutant increased levels of its substrates phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, suggesting that the major phosphoinositide metabolic pathway is impaired. AtPLC2 displayed a distinct tissue expression pattern and localized at the plasma membrane in different cell types, where phosphoinositide signaling occurs. The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth. Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles. Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

No MeSH data available.


Tissue expression of AtPLC2.(A-G) Tissue expression of AtPLC2 by histochemical GUS staining of ProPLC2:PLC2-GUS transgenic plants. (A) Developing rosette leaf of a 7-day-old seedling, (B) developed rosette leaf of a 3-week-old plant, (C) inflorescence with floral buds in different developmental stages, (D) floral bud with developing reproductive organs, (E) mature flower, (F) part of the main root of a 2-week-old seedling and (G) tip of the main root of a 2-week-old seedling. (H-J) Localization of fluorescent PLC2-Venus in roots of 2-week-old seedlings of ProPLC2:PLC2-Venus transgenic plants. (H) Main root, (I) emerging lateral root branch, (J) tip of the main root. Scale bars are 500 μm in (A) to (C), 200 μm in (D) to (G), 100 μm in (H) and (I) and 50 μm in (J).
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pgen.1005511.g004: Tissue expression of AtPLC2.(A-G) Tissue expression of AtPLC2 by histochemical GUS staining of ProPLC2:PLC2-GUS transgenic plants. (A) Developing rosette leaf of a 7-day-old seedling, (B) developed rosette leaf of a 3-week-old plant, (C) inflorescence with floral buds in different developmental stages, (D) floral bud with developing reproductive organs, (E) mature flower, (F) part of the main root of a 2-week-old seedling and (G) tip of the main root of a 2-week-old seedling. (H-J) Localization of fluorescent PLC2-Venus in roots of 2-week-old seedlings of ProPLC2:PLC2-Venus transgenic plants. (H) Main root, (I) emerging lateral root branch, (J) tip of the main root. Scale bars are 500 μm in (A) to (C), 200 μm in (D) to (G), 100 μm in (H) and (I) and 50 μm in (J).

Mentions: AtPLC2 transcript is ubiquitously detected in most of plant tissues as shown in Fig 2B [7,12]; however, little is known about the protein localization of AtPLC2. To explore the tissue localization of AtPLC2 protein, we created a transgenic plant that expresses AtPLC2 fused to a GUS gene driven by the AtPLC2 promoter (ProPLC2:PLC2-GUS). GUS staining was observed in trichomes, particularly at the base, in developing true leaves of ProPLC2:PLC2-GUS transgenic plants (Fig 4A). As the leaves developed, staining was found in leaf vasculature but not at the trichome (Fig 4B). In the inflorescences, staining was found in young buds; entire buds were stained in the early stages (Fig 4C), while carpels and vasculature of petals were stained after the onset of reproductive organ development (Fig 4D). In mature flowers, staining was restricted to the stigma, filament and the boundary region between the filament and stamen (Fig 4E). In roots, GUS staining was found in vasculature (Fig 4F). In addition, intense staining was observed at the branch of lateral roots and root tips. A closer look at the tip of a primary root showed differential patterns of GUS staining: intense and uniform distribution at cell division and elongation zones but restricted staining at vasculature in maturation zones (Fig 4G).


Arabidopsis AtPLC2 Is a Primary Phosphoinositide-Specific Phospholipase C in Phosphoinositide Metabolism and the Endoplasmic Reticulum Stress Response.

Kanehara K, Yu CY, Cho Y, Cheong WF, Torta F, Shui G, Wenk MR, Nakamura Y - PLoS Genet. (2015)

Tissue expression of AtPLC2.(A-G) Tissue expression of AtPLC2 by histochemical GUS staining of ProPLC2:PLC2-GUS transgenic plants. (A) Developing rosette leaf of a 7-day-old seedling, (B) developed rosette leaf of a 3-week-old plant, (C) inflorescence with floral buds in different developmental stages, (D) floral bud with developing reproductive organs, (E) mature flower, (F) part of the main root of a 2-week-old seedling and (G) tip of the main root of a 2-week-old seedling. (H-J) Localization of fluorescent PLC2-Venus in roots of 2-week-old seedlings of ProPLC2:PLC2-Venus transgenic plants. (H) Main root, (I) emerging lateral root branch, (J) tip of the main root. Scale bars are 500 μm in (A) to (C), 200 μm in (D) to (G), 100 μm in (H) and (I) and 50 μm in (J).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4581737&req=5

pgen.1005511.g004: Tissue expression of AtPLC2.(A-G) Tissue expression of AtPLC2 by histochemical GUS staining of ProPLC2:PLC2-GUS transgenic plants. (A) Developing rosette leaf of a 7-day-old seedling, (B) developed rosette leaf of a 3-week-old plant, (C) inflorescence with floral buds in different developmental stages, (D) floral bud with developing reproductive organs, (E) mature flower, (F) part of the main root of a 2-week-old seedling and (G) tip of the main root of a 2-week-old seedling. (H-J) Localization of fluorescent PLC2-Venus in roots of 2-week-old seedlings of ProPLC2:PLC2-Venus transgenic plants. (H) Main root, (I) emerging lateral root branch, (J) tip of the main root. Scale bars are 500 μm in (A) to (C), 200 μm in (D) to (G), 100 μm in (H) and (I) and 50 μm in (J).
Mentions: AtPLC2 transcript is ubiquitously detected in most of plant tissues as shown in Fig 2B [7,12]; however, little is known about the protein localization of AtPLC2. To explore the tissue localization of AtPLC2 protein, we created a transgenic plant that expresses AtPLC2 fused to a GUS gene driven by the AtPLC2 promoter (ProPLC2:PLC2-GUS). GUS staining was observed in trichomes, particularly at the base, in developing true leaves of ProPLC2:PLC2-GUS transgenic plants (Fig 4A). As the leaves developed, staining was found in leaf vasculature but not at the trichome (Fig 4B). In the inflorescences, staining was found in young buds; entire buds were stained in the early stages (Fig 4C), while carpels and vasculature of petals were stained after the onset of reproductive organ development (Fig 4D). In mature flowers, staining was restricted to the stigma, filament and the boundary region between the filament and stamen (Fig 4E). In roots, GUS staining was found in vasculature (Fig 4F). In addition, intense staining was observed at the branch of lateral roots and root tips. A closer look at the tip of a primary root showed differential patterns of GUS staining: intense and uniform distribution at cell division and elongation zones but restricted staining at vasculature in maturation zones (Fig 4G).

Bottom Line: The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth.Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles.Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan; Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Graduate Institute of Biotechnology and Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan; Muroran Institute of Technology, Muroran, Japan.

ABSTRACT
Phosphoinositides represent important lipid signals in the plant development and stress response. However, multiple isoforms of the phosphoinositide biosynthetic genes hamper our understanding of the pivotal enzymes in each step of the pathway as well as their roles in plant growth and development. Here, we report that phosphoinositide-specific phospholipase C2 (AtPLC2) is the primary phospholipase in phosphoinositide metabolism and is involved in seedling growth and the endoplasmic reticulum (ER) stress responses in Arabidopsis thaliana. Lipidomic profiling of multiple plc mutants showed that the plc2-1 mutant increased levels of its substrates phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, suggesting that the major phosphoinositide metabolic pathway is impaired. AtPLC2 displayed a distinct tissue expression pattern and localized at the plasma membrane in different cell types, where phosphoinositide signaling occurs. The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth. Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles. Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

No MeSH data available.