FIGURE 1.

Phakopsora pachyrhizi lesion formation, pre-infection structures formation, and hydrophobicity on CNF-treated soybean leaves. Disease lesions (A) and lesion numbers (B) resulting from P. pachyrhizi infection on the abaxial leaf surface of control, and leaves covered with 0.1% cellulose nanofiber (CNF). Soybean plants were spray-inoculated with P. pachyrhizi (1 × 10⁵ spores/ml). Photographs were taken 10 days after inoculation. Bars indicate 0.2 cm. Lesion numbers were counted to calculate lesion number per cm². Vertical bars indicate the standard error of the means (n = 54). Asterisks indicate a significant difference between control and CNF-treatments in a t-test (**p < 0.01). (C) Urediniospore attachment quantification on the leaf surface of control and leaves covered with 0.1% CNF derived. Soybean plants were spray-inoculated with P. pachyrhizi (1 × 10⁵ spores/ml) and immediately total RNAs including soybean and P. pachyrhizi were purified. Relative expression of soybean ubiquitin 3 (GmUBQ3) and P. pachyrhizi ubiquitin 5 (PpUBQ5) were evaluated using RT-qPCR. Vertical bars indicate the standard error of the means (n = 4). Droplet profiles (D) and quantification of contact angles (E) on the adaxial and abaxial leaf surface of control, and leaves covered with 0.1% CNF derived. Contact angles were evaluated as described in section “Materials and Methods”. Vertical bars indicate the standard error of the means (n = 60). Asterisks indicate a significant difference between control and CNF-treatments in a t-test (**p < 0.01). P. pachyrhizi pre-infection structure formation (F) and percentage of urediniospores (G) on the adaxial and abaxial surfaces of control, and leaves covered with 0.1% CNF, treated with 0.1% DMSO and 500 mM scopoletin (Sco). Soybean plants were spray-inoculated with P. pachyrhizi (1 × 10⁵ spores/ml). The pre-infection structures were stained with Calcofluor White and photographs were taken 6 h after inoculation. Bars indicate 50 μm. The percentage of germinated (Ge) urediniospores and differentiated germ-tubes with appressoria (Ap) were evaluated as described in section “Materials and Methods.” Vertical bars indicate the standard error of the means (n = 21). Significant differences (p < 0.05) are indicated by different letters based on a Tukey’s honestly significant difference (HSD) test.