Strawberry micropropagation simplifies endomicrobiome and highlights potential for in vitro biotization with beneficial rhizobacteria
A. M. G. Sepúlveda, E. da Conceição Jesus, Y. C. Molina, V. H. Buttrós, L. Q. Carvalho, M. Pasqual, J. DóriaAbstract
Strawberry micropropagation produces uniform, disease‐free planting material. However, repeated
in vitro
subculturing can simplify the endophytic microbiome, reducing plant vigour and acclimatization success. This study investigated the impact of successive
in vitro
generations on the endomicrobiome of
Fragaria
×
ananassa
cv. San Andreas and determined if targeted biotization with beneficial rhizobacteria can enhance plant performance.
Profiled endophytic bacterial and fungal communities were analysed in the mother plant and across three
in vitro
generations using amplicon sequencing of the 16S rRNA gene and ITS markers. Ten plant growth‐promoting bacterial strains were tested
in vitro
. The most effective strains were combined into consortia, and their impact on growth, survival and phenolic and flavonoid accumulation was assessed under
in vitro
and
ex vitro
acclimatization conditions.
Successive subcultures simplified the endophytic assemblage. The mother plant exhibited substantially higher bacterial alpha‐diversity than
in vitro
generations, with richness and Shannon diversity declining significantly (
P
<0.001) across all subcultures.
In vitro
biotization with
A. brasilense
Ab‐V5 and
A. brasilense Ab‐V6
increased total dry biomass from 190.63 mg in the control to 216.75 mg and 209.11 mg, respectively. Under
ex vitro
conditions, several inoculated treatments achieved 100% survival compared with 75% in the non‐inoculated control.
Prolonged
in vitro
maintenance reduces the complexity of the strawberry endomicrobiome by imposing a selective bottleneck. Targeted introduction of beneficial bacteria partially compensates by enhancing growth, survival and secondary metabolite accumulation, supporting microbiome‐assisted strategies to improve tissue culture performance and
ex vitro
establishment.