TY - JOUR
T1 - A response surface methodology approach to improve nitrogen use efficiency in maize by an optimal mycorrhiza-to-Bacillus co-inoculation rate
AU - Ganugi, Paola
AU - Fiorini, Andrea
AU - Rocchetti, Gabriele
AU - Bonini, Paolo
AU - Tabaglio, Vincenzo
AU - Lucini, Luigi
PY - 2022
Y1 - 2022
N2 - Co-inoculation of arbuscular mycorrhizal fungi (AMF) and bacteria can synergically and potentially increase nitrogen use efficiency (NUE) in plants, thus, reducing nitrogen (N) fertilizers use and their environmental impact. However, limited research is available on AMF-bacteria interaction, and the definition of synergisms or antagonistic effects is unexplored. In this study, we adopted a response surface methodology (RSM) to assess the optimal combination of AMF (Rhizoglomus irregulare and Funneliformis mosseae) and Bacillus megaterium (a PGPR—plant growth promoting rhizobacteria) formulations to maximize agronomical and chemical parameters linked to N utilization in maize (Zea mays L.). The fitted mathematical models, and also 3D response surface and contour plots, allowed us to determine the optimal AMF and bacterial doses, which are approximately accorded to 2.1 kg ha–1 of both formulations. These levels provided the maximum values of SPAD, aspartate, and glutamate. On the contrary, agronomic parameters were not affected, except for the nitrogen harvest index (NHI), which was slightly affected (p-value of < 0.10) and indicated a higher N accumulation in grain following inoculation with 4.1 and 0.1 kg ha–1 of AMF and B. megaterium, respectively. Nonetheless, the identification of the saddle points for asparagine and the tendency to differently allocate N when AMF or PGPR were used alone, pointed out the complexity of microorganism interaction and suggests the need for further investigations aimed at unraveling the mechanisms underlying this symbiosis.
AB - Co-inoculation of arbuscular mycorrhizal fungi (AMF) and bacteria can synergically and potentially increase nitrogen use efficiency (NUE) in plants, thus, reducing nitrogen (N) fertilizers use and their environmental impact. However, limited research is available on AMF-bacteria interaction, and the definition of synergisms or antagonistic effects is unexplored. In this study, we adopted a response surface methodology (RSM) to assess the optimal combination of AMF (Rhizoglomus irregulare and Funneliformis mosseae) and Bacillus megaterium (a PGPR—plant growth promoting rhizobacteria) formulations to maximize agronomical and chemical parameters linked to N utilization in maize (Zea mays L.). The fitted mathematical models, and also 3D response surface and contour plots, allowed us to determine the optimal AMF and bacterial doses, which are approximately accorded to 2.1 kg ha–1 of both formulations. These levels provided the maximum values of SPAD, aspartate, and glutamate. On the contrary, agronomic parameters were not affected, except for the nitrogen harvest index (NHI), which was slightly affected (p-value of < 0.10) and indicated a higher N accumulation in grain following inoculation with 4.1 and 0.1 kg ha–1 of AMF and B. megaterium, respectively. Nonetheless, the identification of the saddle points for asparagine and the tendency to differently allocate N when AMF or PGPR were used alone, pointed out the complexity of microorganism interaction and suggests the need for further investigations aimed at unraveling the mechanisms underlying this symbiosis.
KW - Bacillus megaterium
KW - Funneliformis mosseae
KW - Rhizoglomus irregulare
KW - biostimulants
KW - nutrients uptake
KW - plant growth promoting rhizobacteria
KW - Bacillus megaterium
KW - Funneliformis mosseae
KW - Rhizoglomus irregulare
KW - biostimulants
KW - nutrients uptake
KW - plant growth promoting rhizobacteria
UR - http://hdl.handle.net/10807/223496
U2 - 10.3389/fpls.2022.956391
DO - 10.3389/fpls.2022.956391
M3 - Article
SN - 1664-462X
VL - 13
SP - 956391-N/A
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
ER -