Fig. 3: Asp/PDPA-NP loosens the cell wall and enhances uptake by Asp transporters.

a, b Cell wall or protoplasmic (a) distribution and (b) accompanying quantification of DiO signal delivered by PDPA-NP or Asp/PDPA-NP in onion scale epidermal cells after plasmolysis. Green fluorescence: DiO signal. Bar = 100 μm. Yellow: protoplasm; pink: apoplastic compartment. Total fluorescence of each cell was determined from Mean ± SEM of three biological replicates, measurement of 15 cells were determined for each replicate. Significant differences were determined using Turkey’s one-way multiple comparison ANOVA test, the P value are as per noted. Data are presented as box-and-whisker plots in (b), where median and 25th and 75th percentiles are represented by the middle line and the box itself, respectively; means are indicated by a “+”. Created in BioRender. Shi, B. (2025) BioRender.com/txwwnta. c GO analysed of differentially expressed genes identified as cell wall remodelling groups at 48 h post spray. Numbers mark the number of differentially expressed genes identified. The y-axis marks the significant change in the scale of the identified differentially expressed genes. d Asp/PDPA-NP@ABA enabled drought resistance are abolished in ataap1 and atlht1 mutants. Three-week-old mutant plants grown under short-day conditions were sprayed (~ 60 μL) with ½ MS medium (MS), 10 μM ABA, PDPA-NP or Asp/PDPA-NP loaded with/without an equivalent of 10 μM ABA. e qPCR analyses of expression profiles of Response to desiccation 29 A (RD29A) in ataap1 and ataap6 mutant plants at 0, 6 and 72 h post foliar spray (n = 3 biological replicates, each replicate is the total RNA extracted from 3 plants. Data are presented as mean values ± SEM. Significant differences were determined using Turkey’s one-way multiple comparison ANOVA test, the P value are as per noted). f Tracking of Asp/PDPA-NP@DiO in Arabidopsis seedling root with/without clathrin inhibitor Tyra23 at 50 μM. Green fluorescence: DiO signal. Bar = 100 μm, n = 3 biological replicates. Data are presented as mean values ± SEM. Significant differences were determined using Student’s two-tailed t-test, the P value are as per noted. Created in BioRender. Shi, B. (2025) BioRender.com/4464gbd. g Schematic illustration of the hypothesis of Asp/PDPA-NP sequentially loosening, and hence transporting within, the cell wall, followed by uptake across the plasma membrane via AAP1 or LHT1 transporter(s). Once within the protoplasm, Asp/PDPA-NP may upregulate expression of cell wall remodelling gene expression to positively feedback to further sustain cell wall loosening. Created in BioRender. Shi, B. (2025) BioRender.com/iz4jut6. Source data are provided as a Source Data file.