(John Wiley & Sons, 2016) Sánchez López, Ángela María; Baslam, Marouane; Muñoz Pérez, Francisco José; Bahaji, Abdellatif; Almagro Zabalza, Goizeder; Ricarte Bermejo, Adriana; García Gómez, Pablo; Baroja Fernández, Edurne; Pozueta Romero, Javier; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua (IIM010491.RI1); Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
It is known that volatile emissions from some beneficial rhizosphere microorganisms promote plant growth. Here we show
that volatile compounds (VCs) emitted by phylogenetically diverse rhizosphere and non-rhizhosphere bacteria and fungi (including plant pathogens and microbes that do not normally
interact mutualistically with plants) promote growth and flowering of various plant species, including crops. In Arabidopsis plants exposed to VCs emitted by the phytopathogen Alternaria alternata, changes included enhancement of
photosynthesis and accumulation of high levels of cytokinins (CKs) and sugars. Evidence obtained using transgenic Arabidopsis plants with altered CK status show that CKs play essential roles in this phenomenon, because growth and
flowering responses to the VCs were reduced in mutants with CK-deficiency (35S:AtCKX1) or low receptor sensitivity (ahk2/3). Further, we demonstrate that the plant responses to fungal VCs are light-dependent. Transcriptomic analyses of
Arabidopsis leaves exposed to A. alternata VCs revealed changes in the expression of light- and CK-responsive genes involved in photosynthesis, growth and flowering. Notably, many
genes differentially expressed in plants treated with fungal VCs were also differentially expressed in plants exposed to VCs emitted by the plant growth promoting rhizobacterium Bacillus subtilis GB03, suggesting that plants react to microbial
VCs through highly conserved regulatory mechanisms.
