Branched-chain amino acid biosynthesis inhibitors: herbicide efficacy is associated with an induced carbon–nitrogen imbalance
Fecha
2013Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión aceptada / Onetsi den bertsioa
Impacto
|
10.1016/j.jplph.2013.01.003
Resumen
Acetolactate synthase (ALS; EC 4.1.3.18) and ketol-acid reductoisomerase (KARI; EC 1.1.1.86) are two consecutive enzymes in the biosynthesis of branched-chain amino acids. Several commercial herbicides inhibit ALS as their primary site of action. KARI has also attracted attention as a potential target for herbicides. Although potent and selective inhibitors of KARI have been discovered, these inh ...
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Acetolactate synthase (ALS; EC 4.1.3.18) and ketol-acid reductoisomerase (KARI; EC 1.1.1.86) are two consecutive enzymes in the biosynthesis of branched-chain amino acids. Several commercial herbicides inhibit ALS as their primary site of action. KARI has also attracted attention as a potential target for herbicides. Although potent and selective inhibitors of KARI have been discovered, these inhibitors display less herbicidal activity than ALS-inhibiting herbicides. To obtain a better understanding of these findings, we have compared the physiological effects induced in pea plants after KARI or ALS inhibition. Although, both types of inhibitors induce growth arrest and photosynthesis inhibition, plant death occurs more rapidly under ALS inhibition than KARI inhibition. Carbohydrates accumulated in the leaves and roots following treatments with both inhibitors. The carbohydrate accumulation in the leaves occurred as a consequence of a decrease in sink strength. In contrast, the free amino acid content was only affected through ALS inhibition. These results indicate that although KARI and ALS inhibition block the same biosynthetic pathway and exert common effects on carbon metabolism, nitrogen metabolism is more affected via ALS than KARI inhibition. Thus, metabolic alterations in nitrogen metabolism induced through ALS inhibitors might contribute to the increased efficacy of these chemicals as herbicides. [--]
Materias
Mode of action,
Herbicide,
Branched-chain amino acid,
Acetolactate synthase,
Ketol-acid reductoisomerase
Editor
Elsevier
Publicado en
Journal of Plant Physiology 170 (2013) 814–821
Departamento
Universidad Pública de Navarra. Departamento de Ciencias del Medio Natural /
Nafarroako Unibertsitate Publikoa. Natura Ingurunearen Zientziak Saila
Versión del editor
Entidades Financiadoras
M. Igal received a grant from the Public University of
Navarre. A. Zulet and M. Gil-Monreal receive funding through fellowships
from the Spanish Ministry of Education and the Public
University of Navarre, respectively. This work was financially supported
through grants from the Spanish Ministry of Education and
Science (AGL-2010-18621).