Chlorophyll degradation: The tocopherol Biosynthesis-Related phytol hydrolase in arabidopsis seeds is still missing

Wei Zhang, Tianqi Liu, Guodong Ren, Stefan HɆrtensteiner, Yongming Zhou, Edgar B. Cahoon, Chunyu Zhang

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type overexpressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis.

Original languageEnglish (US)
Pages (from-to)70-79
Number of pages10
JournalPlant physiology
Volume166
Issue number1
DOIs
StatePublished - Sep 1 2014

Fingerprint

Phytol
Tocopherols
Hydrolases
Chlorophyll
hydrolases
tocopherols
Arabidopsis
Seeds
biosynthesis
chlorophyll
degradation
Pheophytins
seeds
Enzymes
enzymes
chlorophyllase
mutants
Biosynthetic Pathways

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

Cite this

Chlorophyll degradation : The tocopherol Biosynthesis-Related phytol hydrolase in arabidopsis seeds is still missing. / Zhang, Wei; Liu, Tianqi; Ren, Guodong; HɆrtensteiner, Stefan; Zhou, Yongming; Cahoon, Edgar B.; Zhang, Chunyu.

In: Plant physiology, Vol. 166, No. 1, 01.09.2014, p. 70-79.

Research output: Contribution to journalArticle

Zhang, Wei ; Liu, Tianqi ; Ren, Guodong ; HɆrtensteiner, Stefan ; Zhou, Yongming ; Cahoon, Edgar B. ; Zhang, Chunyu. / Chlorophyll degradation : The tocopherol Biosynthesis-Related phytol hydrolase in arabidopsis seeds is still missing. In: Plant physiology. 2014 ; Vol. 166, No. 1. pp. 70-79.
@article{d0cd0b11dd1547dc8064816a4c989930,
title = "Chlorophyll degradation: The tocopherol Biosynthesis-Related phytol hydrolase in arabidopsis seeds is still missing",
abstract = "Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type overexpressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis.",
author = "Wei Zhang and Tianqi Liu and Guodong Ren and Stefan HɆrtensteiner and Yongming Zhou and Cahoon, {Edgar B.} and Chunyu Zhang",
year = "2014",
month = "9",
day = "1",
doi = "10.1104/pp.114.243709",
language = "English (US)",
volume = "166",
pages = "70--79",
journal = "Plant Physiology",
issn = "0032-0889",
publisher = "American Society of Plant Biologists",
number = "1",

}

TY - JOUR

T1 - Chlorophyll degradation

T2 - The tocopherol Biosynthesis-Related phytol hydrolase in arabidopsis seeds is still missing

AU - Zhang, Wei

AU - Liu, Tianqi

AU - Ren, Guodong

AU - HɆrtensteiner, Stefan

AU - Zhou, Yongming

AU - Cahoon, Edgar B.

AU - Zhang, Chunyu

PY - 2014/9/1

Y1 - 2014/9/1

N2 - Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type overexpressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis.

AB - Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type overexpressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis.

UR - http://www.scopus.com/inward/record.url?scp=84907046849&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84907046849&partnerID=8YFLogxK

U2 - 10.1104/pp.114.243709

DO - 10.1104/pp.114.243709

M3 - Article

C2 - 25059706

AN - SCOPUS:84907046849

VL - 166

SP - 70

EP - 79

JO - Plant Physiology

JF - Plant Physiology

SN - 0032-0889

IS - 1

ER -