Boron deficiency inhibits root cell elongation via an ethylene/auxin/ROS-dependent pathway in Arabidopsis seedlings.
One of the earliest symptoms of boron (B) deficiency is the inhibition of root elongation which can reasonably be attributed to the damaging effects of B deprivation on cell wall integrity. It is shown here that exposure of wild-type Arabidopsis thaliana seedlings to B deficiency for 4h led to a drastic inhibition of root cell length in the transition between the elongation and differentiation zones. To investigate the possible mediation of ethylene, auxin, and reactive oxygen species (ROS) in the effect of B deficiency on root cell elongation, B deficiency was applied together with aminoethoxyvinylglycine (AVG, a chemical inhibitor of ethylene biosynthesis), silver ions (Ag(+), an antagonist of ethylene perception), α-(phenylethyl-2-oxo)-indoleacetic acid (PEO-IAA, a synthetic antagonist of TIR1 receptor function), and diphenylene iodonium (DPI, an inhibitor of ROS production). Interestingly, all these chemicals partially or fully restored cell elongation in B-deficient roots. To further explore the possible role of ethylene and auxin in the inhibition of root cell elongation under B deficiency, a genetic approach was performed by using Arabidopsis mutants defective in the ethylene (ein2-1) or auxin (eir1-4 and aux1-22) response. Root cell elongation in these mutants was less sensitive to B-deficient treatment than that in wild-type plants. Altogether, these results demonstrated that a signalling pathway involving ethylene, auxin, and ROS participates in the reduction of root cell elongation when Arabidopsis seedlings are subjected to B deficiency. A similar signalling process has been described to reduce root elongation rapidly under various types of cell wall stress which supports the idea that this signalling pathway is triggered by the impaired cell wall integrity caused by B deficiency.
Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013, Sevilla, Spain jjcamcri@upo.es.
Juan J
http://orcid.org/0000-0001-7758-1868
JJ
Camacho-Cristóbal
Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013, Sevilla, Spain.
Esperanza M
EM
Martín-Rejano
Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013, Sevilla, Spain.
M Begoña
MB
Herrera-Rodríguez
Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013, Sevilla, Spain.
M Teresa
MT
Navarro-Gochicoa
Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013, Sevilla, Spain.
Jesús
J
Rexach
Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013, Sevilla, Spain.
Agustín
A
González-Fontes
D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001895:Boron / Q000172:deficiency*; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000494:pharmacology; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
D000598:Amino Acids, Cyclic; D029681:Arabidopsis Proteins; D005030:Ethylenes; D007210:Indoleacetic Acids; D009943:Organophosphorus Compounds; D017382:Reactive Oxygen Species; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene; D001895:Boron; C005073:ethephon
Arabidopsis; auxin; boron; ethylene; reactive oxygen species; root elongation.