Arabidopsis γ-glutamylcyclotransferase affects glutathione content and root system architecture during sulfur starvation

TY - JOUR

T1 - Arabidopsis γ-glutamylcyclotransferase affects glutathione content and root system architecture during sulfur starvation

AU - Joshi, Naveen C.

AU - Meyer, Andreas J.

AU - Bangash, Sajid A.K.

AU - Zheng, Zhi Liang

AU - Leustek, Thomas

N1 - Publisher Copyright: © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust

PY - 2019/2/1

Y1 - 2019/2/1

N2 - γ-Glutamylcyclotransferase initiates glutathione degradation to component amino acids l-glutamate, l-cysteine and l-glycine. The enzyme is encoded by three genes in Arabidopsis thaliana, one of which (GGCT2;1) is transcriptionally upregulated by starvation for the essential macronutrient sulfur (S). Regulation by S-starvation suggests that GGCT2;1 mobilizes l-cysteine from glutathione when there is insufficient sulfate for de novo l-cysteine synthesis. The response of wild-type seedlings to S-starvation was compared to ggct2;1 null mutants. S-starvation causes glutathione depletion in S-starved wild-type seedlings, but higher glutathione is maintained in the primary root tip than in other seedling tissues. Although GGCT2;1 is induced throughout seedlings, its expression is concentrated in the primary root tip where it activates the γ-glutamyl cycle. S-starved wild-type plants also produce longer primary roots, and lateral root growth is suppressed. While glutathione is also rapidly depleted in ggct2;1 null seedlings, much higher glutathione is maintained in the primary root tip compared to the wild-type. S-starved ggct2;1 primary roots grow longer than the wild-type, and lateral root growth is not suppressed. These results point to a role for GGCT2;1 in S-starvation-response changes to root system architecture through activity of the γ-glutamyl cycle in the primary root tip. l-Cysteine mobilization from glutathione is not solely a function of GGCT2;1.

AB - γ-Glutamylcyclotransferase initiates glutathione degradation to component amino acids l-glutamate, l-cysteine and l-glycine. The enzyme is encoded by three genes in Arabidopsis thaliana, one of which (GGCT2;1) is transcriptionally upregulated by starvation for the essential macronutrient sulfur (S). Regulation by S-starvation suggests that GGCT2;1 mobilizes l-cysteine from glutathione when there is insufficient sulfate for de novo l-cysteine synthesis. The response of wild-type seedlings to S-starvation was compared to ggct2;1 null mutants. S-starvation causes glutathione depletion in S-starved wild-type seedlings, but higher glutathione is maintained in the primary root tip than in other seedling tissues. Although GGCT2;1 is induced throughout seedlings, its expression is concentrated in the primary root tip where it activates the γ-glutamyl cycle. S-starved wild-type plants also produce longer primary roots, and lateral root growth is suppressed. While glutathione is also rapidly depleted in ggct2;1 null seedlings, much higher glutathione is maintained in the primary root tip compared to the wild-type. S-starved ggct2;1 primary roots grow longer than the wild-type, and lateral root growth is not suppressed. These results point to a role for GGCT2;1 in S-starvation-response changes to root system architecture through activity of the γ-glutamyl cycle in the primary root tip. l-Cysteine mobilization from glutathione is not solely a function of GGCT2;1.

KW - cysteine

KW - glutathione

KW - nutrient foraging

KW - root system architecture

KW - sulfur (S)

KW - γ-glutamyl-cyclotransferase

UR - https://www.scopus.com/pages/publications/85055701244

UR - https://www.scopus.com/pages/publications/85055701244#tab=citedBy

U2 - 10.1111/nph.15466

DO - 10.1111/nph.15466

M3 - Article

C2 - 30368820

SN - 0028-646X

VL - 221

SP - 1387

EP - 1397

JO - New Phytologist

JF - New Phytologist

IS - 3

ER -