Improving callus regeneration of Miscanthus × giganteus J.M.Greef,Deuter ex Hodk., Renvoize ‘M161’ callus by inhibition of the phenylpropanoid biosynthetic pathway

In previous studies, the regeneration rates of Miscanthus × giganteus J.M.Greef, Deuter ex Hodk., Renvoize from callus tissue cultured on semi-solid media significantly declined after 4 mo of culture, which presents problems with germplasm conservation and use as an alternative propagation system. Due to the species’ lignocellulosic nature, it was hypothesized that the accumulation of phenolic compounds in the callus may be responsible for inhibiting regeneration. The current study aimed to optimize regeneration of M. × giganteus callus by culturing the callus tissue in the presence of 2-aminoindan-2-phosphonic acid (AIP), a competitive inhibitor of phenylalanine ammonia lyase (PAL), to reduce the biosynthesis of phenolics. Embryogenic callus was cultured on media supplemented with 9.0- or 11.3-μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0-, 1-, 10-, 100-, or 1000-μM AIP. Every 28 d for 7 mo, the callus tissue was visually classified based on morphology and regeneration rate. Over the duration of the study, regeneration of shoots was consistently highest in callus cultured on 11.3-μM 2,4-D supplemented with 10- and 100-μM AIP (13–58.3%), and in vitro plantlet development from callus cultured on all concentrations of AIP demonstrated tillering and rooting. Total soluble phenolic content of the callus decreased in a dose-dependent manner from 2242.34-μg g⁻¹ dry weight in the control to 1569.71-μg g⁻¹ dry weight in AIP-treated callus. These data indicate that inhibiting PAL in M. × giganteus cultures increased the percentage of calluses exhibiting regeneration over time.

     

Linking properties of an orb‐weaving spider's capture thread glycoprotein adhesive and flagelliform fiber components to prey retention time

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