Figure 6.

Evaluation of heat‐stress tolerance during grain filling of rice with overexpression of MSD1 (MSD1^OE) or developing endosperm‐specific suppression of MSD1 (MSD1^KD). (a–c) Expression profiles of MSD1 mRNA in different organs of Nipponbare wild type (WT) and MSD1^OE. (a) Leaf blades and (b) roots at vegetative stage and (c) developing grains at 5 days after flowering (DAF) were harvested and used for fluorescence‐based quantitative real‐time PCR. Values are means ± SD (n = 3). (d–f) Nipponbare WT and MSD1^OE plants were incubated under (d) 28/23 °C (12/12 h), (e) 30/23 °C (12/12 h) or (f) 33/28 °C (12/12 h) after heading, and the appearance quality of harvested grains was evaluated. Values are means ± SD (n = 3–7) of proportions of perfect grains. (g, h) Nipponbare WT and MSD1^KD plants were incubated under 33/28 °C after heading; MSD1 mRNA in developing grains at 5 DAF was quantified and appearance quality was evaluated (n = 5). (i, j) Yukinkomai WT and MSD1^KD plants were incubated under 33/28 °C after heading; MSD1 mRNA in developing grains at 5 DAF was quantified, and appearance quality was evaluated (n = 3–7). The ratio of MSD1 mRNA to 18S rRNA in each WT was set to 1. Columns with the same letter are not significantly different (P < 0.05, Student's t‐test).