Nuclear protein delivery underlies an array of biotechnological and therapeutic applications. While many variations of protein delivery methods have been described, it can still be difficult or inefficient to introduce exogenous proteins into plants. A major barrier to progress is the cell wall which is primarily composed of polysaccharides and thus only permeable to small molecules. Here, we report a partial enzymatic cell wall digestion-mediated uptake method that efficiently delivers protein into the nucleus of plant cells. Such a method allowed efficient nuclear delivery of green fluorescent protein (GFP) flanked by two nuclear localization sequences (NLS) into Arabidopsis thaliana epidermal root cells without the usual need for large doses of nanoparticles or tissue cultures. We also show that switching from daylight to far-red light-grown conditions promotes effective protein penetration into deep cell layers. This study establishes that a partial enzymatic cell wall degradation could be applied to other cell organelles by changing the localization sequence, paving the way toward the rational engineering of plants.

Anionic polyelectrolytes, such as DNA, are attracted to anionic surfaces in the presence of multivalent cations. A major barrier toward molecular-level understanding of these attractive interactions is the paucity of measurements of the binding strength. Here, atomic force microscopy-based single molecule force spectroscopy was used to quantify the binding free energy of double-stranded DNA to an anionic surface, with complementary density functional theory calculations of the binding energies of metal ion-ligand complexes. The results support both electrostatic attraction and ion-specific binding. Our study suggests that the correlated interactions between counterions are responsible for attraction between DNA and an anionic surface, but the strength of this attraction is modulated by the identity of the metal ion. We propose a mechanism in which the strength of metal-ligand binding, as well as the preference for particular binding sites, influence both the concentration dependence and the strength of the DNA-surface interactions.