Suppression of phospholipase D genes improves chalky grain production by high temperature during the grain-filling stage in rice

Figures & data

Figure 1. Changes in chalky grain production of the PLD gene-KD plants in HT growth conditions.

(a) Each plant was grown in a greenhouse in normal conditions (27°C/25°C) before flowering, and then it was grown in HT conditions (33°C/29°C). Values represent the ratio of chalky grains and average of triplicate experiments of two individual plants, and the error bars indicate SD. The symbols, *, **, and *** indicate a significant difference from the control (HT) at the 0.2%, 0.03%, and 0.01% levels, respectively, as determined by using Student’s t-test. (b) Appearance of grains. (c) Accumulation of OsPLDα1, OsPLDα3, or OsPLDβ2 mRNAs in the grains of the OsPLDα1-KD, OsPLDα3-KD, OsPLDβ2-KD, or vector-control plants in HT growth conditions. Homozygote KD and vector-control plants were grown in a greenhouse, and after flowering they were grown in HT conditions. Total RNA was extracted from grains at 10 DAF. The values were standardized using the expression level of a rice polyubiqutin gene (RUBIQ1). Values represent the averages of three individual plants, and the error bars indicate SD.

Figure 2. Accumulation of H₂O₂ (a) and ROS-scavenging activity (b) in developing grain grown in normal or HT conditions. Each plant was grown in a greenhouse in normal conditions (27°C/25°C) before flowering and then, it was grown under normal or high temperature conditions (33°C/29°C). Each test sample was harvested at 10 DAF. (a) H₂O₂ was analyzed in the grains using the luminol chemiluminescence method. Values represent averages of triplicate experiments of three individual plants, and the error bars indicate SD. (b) The catalase-like activity was analyzed using H₂O₂ as a substrate. The values represent the average of triplicate experiments of three individual plants, and the error bars indicate SD. The symbol indicates a significant difference from the control plants at the 0.2% level.

Figure 3. Accumulation of OsCATA, OsCATB, or OsCATC mRNA in the grains of the vector-control or OsPLDβ2-KD plants in HT growth conditions. Each plant was grown in a greenhouse, and after flowering they were grown in HT conditions. Total RNA was extracted from the grains at 10 DAF. The values were standardized using the expression levels of a rice polyubiqutin gene (RUBIQ1). Values represent the average of triplicate experiments of three individual plants, and the error bars indicate SD. The symbol indicates a significant difference from the control at the 0.05% level.

Figure 4. Changes in chalky grain production of the catalase gene overexpression plants in HT growth conditions. (a) Each plant was grown in a greenhouse in normal conditions (27°C/25°C) before flowering, and then it was grown in HT conditions (33°C/29°C). Values represent the ratio of chalky grains and the average of triplicate experiments, and the error bars indicate SD. The symbol indicates a significant difference from the control plants (HT) at the 0.01% level. (b) Appearance of grains. (c) Accumulation of OsCATA, OsCATB, or OsCATC mRNA in the grains of the OsCATA-ox, OsCATB-ox, OsCATC-ox, or vector-control plants in HT growth conditions. The homozygote ox and vector-control plants were grown in a greenhouse and after flowering they were grown in HT conditions. Total RNA was extracted from the grains at 10 DAF. Values were standardized to the expression levels of a rice polyubiqutin gene (RUBIQ1). Values represent the average of three individual plants, and the error bars indicate SD.