Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Glutamate signalling via a MEKK1 kinase-dependent pathway induces changes in Arabidopsis root architecture
AU - Forde, Brian
AU - Cutler, Sean
AU - Zaman, Najia
AU - Krysan, Patrick
PY - 2013/7
Y1 - 2013/7
N2 - A chemical genetic approach has been used to investigate the mechanism by which external glutamate (L-Glu) is able to trigger major changes in root architecture in Arabidopsis thaliana L. An initial screen of 80 agonists and antagonists of mammalian glutamate and GABA receptors using a specially developed 96-well micro-phenotyping system found none that either replicated the root’s response to L-Glu or antagonised it. However, a larger screen using >1500 molecules bioactive in yeast identified two groups that interfered with the L-Glu response. One of the antagonists, 2-(4-chloro-3-methylphenyl)-2-oxoethyl thiocyanate (CMOT), has been reported to target Ste11, an evolutionarily conserved MAP kinase kinase kinase (MAP3K) in yeast. This led to the discovery that root growth in a triple mekk1/mekk2/mekk3 mutant (mekk1/2/3), defective in a set of three tandemly arranged MAP3Ks, was almost insensitive to L-Glu. However, the sensitivity of mekk1/2/3 roots to inhibition by other amino acids reported to act as agonists of glutamate receptor-like (GLR) channels in Arabidopsis roots (Asn, Cys, Gly and Ser) was unaffected. L-Glu sensitivity of the mekk1/2/3 mutant was restored by transformation with a construct carrying the intact MEKK1 gene. These results demonstrate that MEKK1 plays a key role in transducing the L-Glu signal that elicits large-scale changes in root architecture and provide genetic evidence for the existence in plants of an L-Glu signalling pathway analogous to that found in animals.
AB - A chemical genetic approach has been used to investigate the mechanism by which external glutamate (L-Glu) is able to trigger major changes in root architecture in Arabidopsis thaliana L. An initial screen of 80 agonists and antagonists of mammalian glutamate and GABA receptors using a specially developed 96-well micro-phenotyping system found none that either replicated the root’s response to L-Glu or antagonised it. However, a larger screen using >1500 molecules bioactive in yeast identified two groups that interfered with the L-Glu response. One of the antagonists, 2-(4-chloro-3-methylphenyl)-2-oxoethyl thiocyanate (CMOT), has been reported to target Ste11, an evolutionarily conserved MAP kinase kinase kinase (MAP3K) in yeast. This led to the discovery that root growth in a triple mekk1/mekk2/mekk3 mutant (mekk1/2/3), defective in a set of three tandemly arranged MAP3Ks, was almost insensitive to L-Glu. However, the sensitivity of mekk1/2/3 roots to inhibition by other amino acids reported to act as agonists of glutamate receptor-like (GLR) channels in Arabidopsis roots (Asn, Cys, Gly and Ser) was unaffected. L-Glu sensitivity of the mekk1/2/3 mutant was restored by transformation with a construct carrying the intact MEKK1 gene. These results demonstrate that MEKK1 plays a key role in transducing the L-Glu signal that elicits large-scale changes in root architecture and provide genetic evidence for the existence in plants of an L-Glu signalling pathway analogous to that found in animals.
KW - amino acids
KW - chemical genetics
KW - nutrient signalling
KW - roots
KW - signal transduction
KW - Arabidopsis thaliana L.
KW - MAP kinase
KW - Saccharomyces cerevisiae
UR - http://www.scopus.com/inward/record.url?scp=84879245087&partnerID=8YFLogxK
U2 - 10.1111/tpj.12201
DO - 10.1111/tpj.12201
M3 - Journal article
AN - SCOPUS:84879245087
VL - 75
SP - 1
EP - 10
JO - Plant Journal
JF - Plant Journal
SN - 0960-7412
IS - 1
ER -