Molecular changes in Pisum sativum L. roots during arbuscular mycorrhiza buffering of cadmium stress.
Molecular responses to cadmium (Cd) stress were studied in mycorrhizal and non-mycorrhizal Pisum sativum L. cv. Frisson inoculated with Glomus intraradices. Biomass decreases caused by the heavy metal were significantly less in mycorrhizal than in non-mycorrhizal plants. Real-time reverse transcriptase-polymerase chain reaction showed that genes implicated in pathways of Cd detoxification varied in response to mycorrhiza development or Cd application. Expression of a metallothionein-encoding gene increased strongly in roots of Cd-treated non-mycorrhizal plants. Genes encoding gamma-glutamylcysteine synthetase and glutathione (GSH) synthetase, responsible for the synthesis of the phytochelatin (PC) precursor GSH, were activated by Cd in mycorrhizal and non-mycorrhizal plants. Cd stress decreased accumulation of GSH/homoglutathione (hGSH) and increased thiol groups in pea roots, whether mycorrhizal or not, suggesting synthesis of PCs and/or homophytochelatins. An hGSH synthetase gene, involved in hGSH synthesis, did not respond to Cd alone but was activated by mycorrhizal development in the presence of Cd. Transcript levels of a glutathione reductase gene were only increased in non-mycorrhizal roots treated with Cd. Studies of three stress-related genes showed that a heat-shock protein gene was activated in mycorrhizal roots or by Cd and chitinase gene transcripts increased under Cd stress to a greater extent in mycorrhizal roots, whilst a chalcone isomerase gene was only up-regulated by Cd. Results indicate that although heavy metal chelation pathways contribute to Cd stress responses in pea, they may not make a major contribution to Cd tolerance strategies operating in the arbuscular mycorrhizal symbiosis.
Rivera-Becerril
Facundo
F
UMR 1088 INRA/5184 CNRS/U., Bourgogne Plante-Microbe-Environnement, INRA-CMSE, BP 86510, 21065, Dijon Cédex, France.|Depto. El Hombre y su Ambiente, CBS, Universidad Autónoma Metropolitana-Xochimilco, Calz. del Hueso 1100, Col. Villa Quietud, 04960, México DF, Mexico.
van Tuinen
Diederik
D
UMR 1088 INRA/5184 CNRS/U., Bourgogne Plante-Microbe-Environnement, INRA-CMSE, BP 86510, 21065, Dijon Cédex, France.
Martin-Laurent
Fabrice
F
Microbiologie et Géochimie des Sols, UMR A111 INRA/U. Bourgogne, BP 86510, 21065, Dijon Cédex, France.
Metwally
Ashraf
A
Department of Physiology and Biochemistry of Plants, University of Bielefeld, Universitätstraße 25, 33501, Bielefeld, Germany.|Botany Department, Faculty of Science, Assiut University, 71516, Assiut, Egypt.
Dietz
Karl-Josef
KJ
Department of Physiology and Biochemistry of Plants, University of Bielefeld, Universitätstraße 25, 33501, Bielefeld, Germany.
Gianinazzi
Silvio
S
UMR 1088 INRA/5184 CNRS/U., Bourgogne Plante-Microbe-Environnement, INRA-CMSE, BP 86510, 21065, Dijon Cédex, France.
Gianinazzi-Pearson
Vivienne
V
UMR 1088 INRA/5184 CNRS/U., Bourgogne Plante-Microbe-Environnement, INRA-CMSE, BP 86510, 21065, Dijon Cédex, France. Vivienne.Gianinazzi-Pearson@epoisses.inra.fr.
D000222:Adaptation, Physiological; D018533:Biomass; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity*; D002688:Chitinases / Q000096:biosynthesis / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics; D005658:Fungi / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005721:Glutamate-Cysteine Ligase / Q000096:biosynthesis / Q000235:genetics; D005978:Glutathione / Q000031:analogs & derivatives / Q000032:analysis; D005981:Glutathione Synthase / Q000096:biosynthesis / Q000235:genetics; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D008668:Metallothionein / Q000096:biosynthesis / Q000235:genetics; D038821:Mycorrhizae / Q000378:metabolism*; D018532:Pisum sativum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects* / Q000382:microbiology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013438:Sulfhydryl Compounds / Q000032:analysis
D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D013438:Sulfhydryl Compounds; C402172:homoglutathione; D002104:Cadmium; D008668:Metallothionein; D002688:Chitinases; D005721:Glutamate-Cysteine Ligase; D005981:Glutathione Synthase; D005978:Glutathione