Shandong Academy of Agricultural Sciences, Jinan, Shandong, China.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.
Mol Biol Rep. 2019 Aug;46(4):3937-3944. doi: 10.1007/s11033-019-04840-5. Epub 2019 Apr 30.
Maize (Zea mays L.) is an important model plant with an important role in agriculture and national economies all over the world. The optimum growth temperature of maize is between 25 and 28 °C. At temperatures below 12 °C, maize is vulnerable to damage by chilling stress. MYB transcription factors play important roles in plants' response to low temperature stress. Maize ZmMYB31 encodes a R2R3-MYB transcription factor, ZmMYB31, which localized in the nucleus. ZmMYB31 expression was induced by chilling stress and the highest expression level was detected with the 24 h chilling treatment. ZmMYB31 expression also increased in overexpressing Arabidopsis lines. The minimal fluorescence (Fo) with all photosystem II reaction centers open increased in wild type (WT) and transgenic plants under chilling stress, with the highest increase in WT. The maximal photochemical efficiency of photosystem II (Fv/Fm) decreased more in WT than in transgenic plants during chilling stress. Furthermore, the ZmMYB31-overexpressing lines showed higher superoxide dismutase and ascorbate peroxidase activity and lower reactive oxygen species (ROS) content than the WT. The expression of genes related to chilling stress was higher in transgenic plants than in WT. These results suggest that ZmMYB31 plays a positive regulatory role in chilling and peroxide stress by regulating the expression of chilling stress-related genes to reduce ion extravasation, ROS content, and low-temperature photoinhibition, thereby improving low temperature resistance.
玉米（Zea mays L.）是一种重要的模式植物，在世界各国的农业和国民经济中都具有重要作用。玉米的最佳生长温度在 25 到 28°C 之间。在 12°C 以下的温度下，玉米容易受到冷胁迫的伤害。MYB 转录因子在植物对低温胁迫的反应中起着重要作用。玉米 ZmMYB31 编码一个 R2R3-MYB 转录因子，ZmMYB31，它定位于细胞核中。ZmMYB31 的表达受冷胁迫诱导，在 24 小时冷胁迫处理时检测到最高表达水平。ZmMYB31 的表达在过表达拟南芥系中也增加了。在冷胁迫下，野生型（WT）和转基因植物的所有光合系统 II 反应中心开放的最小荧光（Fo）增加，WT 中的增加最大。冷胁迫下，WT 中光系统 II 的最大光化学效率（Fv/Fm）下降幅度大于转基因植物。此外，ZmMYB31 过表达系的超氧化物歧化酶和抗坏血酸过氧化物酶活性高于 WT，活性氧（ROS）含量低于 WT。与冷胁迫相关的基因在转基因植物中的表达高于 WT。这些结果表明，ZmMYB31 通过调节与冷胁迫相关基因的表达，在冷胁迫和过氧化物胁迫中发挥正向调节作用，从而减少离子渗出、ROS 含量和低温光抑制，提高低温抗性。
