Figure 1.

(a) GRFT accumulation in rice endosperm. An immunoglobulin‐specific sandwich ELISA was used to screen the three best‐performing independent events. The ELISA plate was coated with gp120, and GRFT protein assembly was confirmed using a primary rabbit anti‐GRFT polyclonal antiserum and a secondary HRP‐conjugated anti‐rabbit IgG antiserum. Four serial dilutions per sample are shown (neat, 1/2, 1/4 and 1/8). WT, wild‐type extracts; C⁻, negative control (PBS); C⁺, GRFT purified from E. coli (500 ng/mL) as a positive control. OD, optical density at 450 nm. (b) Transformation construct pgZ63‐GRFT for the stable expression of GRFT in rice endosperm. The expression cassette comprised the endosperm‐specific maize zein promoter, the rice α‐amylase 3A signal peptide sequence (SP), a His₆ tag, the GRFT coding region (grft) and the nos terminator (t‐nos).