Fig. 4
VitB1 estimation in different samples using thi6 yeast microbiological assay. The thi6 yeast assay, as described, was used to assess vitB1 content in different samples. An estimate of vitB1 content was obtained for brown (unpolished) (A) and polished (B) rice, including wild type (WT) and different genetic backgrounds generated in an earlier biofortification project via genetic engineering [29]. Values represent means ± standard deviation (SD) of 3 (WT, N = 6) biological repeats, each consisting of 2 technical replicates. Significant differences (p < 0.01; 2 asterisks; 0.01 < p < 0.05, 1 asterisk) were evaluated via a 2-sided Student’s t-test, of which the scedasticity was depending on the outcome of the F-test, as wild type values were found to depict normal distribution (Shapiro–Wilk test) allowing for parametric tests. Comparison of brown vs. polished wild type rice seeds revealed a significant (p < 0.001) drop in vitB1 upon polishing