Frequently occurring drought stress negatively affects the production of maize worldwide. Numerous efforts have been made to develop drought-tolerant maize lines and to explore drought tolerant mechanisms in maize. However, there is a lack of comparative studies on transcriptomic changes between drought-tolerant and control maize lines. In the present study, we have developed a drought-tolerant maize mutant (C7–2t) by irradiating the seeds of maize inbred line ChangC7–2 (C7–2) with 60Co-γ. Compared to its wild type C7–2, C7–2t exhibited a significantly delayed wilting and higher drought tolerance under both the controlled and field conditions, indicating its high water-holding ability. Transcriptomic profiling was performed to identify differentially expressed genes (DEGs) between C7–2 and C7–2t during drought. As a result, a total of 4552 DEGs were implied in drought tolerance of C7-2 and C7-2t. In particular, the expression of photosynthesis-related genes in C7–2 was inhibited, whereas these genes in C7–2t were almost unaffected under drought. Moreover, a specific set of the DEGs were involved in phenylpropanoid biosynthesis and taurine (hypotaurine) metabolism in C7–2t; these DEGs were enriched in cell components associated with membrane systems and cell wall biosynthesis. The drought tolerance of C7–2t was largely due to its high water-holding ability, stable photosynthesis (for supporting osmoregulation) and strengthened biosynthesis of cell walls under drought conditions.

中文翻译：

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基于生理，生化和转录组学分析，鉴定耐旱玉米突变体中的耐旱机制。

经常发生的干旱胁迫对全世界玉米的生产产生负面影响。已经做出了许多努力来开发玉米的耐旱品系，并探索玉米的耐旱机理。但是，目前尚缺乏关于耐旱玉米和对照玉米之间转录组变化的比较研究。在本研究中，我们通过用60Co-γ辐照玉米自交系ChangC7-2（C7-2）的种子，开发了一种耐旱的玉米突变体（C7-2t）。与野生型C7–2相比，C7–2t在受控和田间条件下均表现出明显的枯萎延迟和较高的耐旱性，表明其具有较高的持水能力。进行了转录组分析，以鉴定干旱期间C7–2和C7–2t之间的差异表达基因（DEG）。结果是，总共4552个DEG暗示了C7-2和C7-2t的耐旱性。特别是，光合作用相关基因在C7–2中的表达受到抑制，而C7–2t中的这些基因在干旱下几乎不受影响。此外，在C7–2t中，一组特定的DEG参与了苯丙烷的生物合成和牛磺酸（hypotaurine）的代谢。这些DEG富含与膜系统和细胞壁生物合成相关的细胞成分。C7-2t的耐旱性主要是由于其高持水能力，稳定的光合作用（用于支持渗透调节）和在干旱条件下增强了细胞壁的生物合成。而C7-2t中的这些基因在干旱下几乎不受影响。此外，在C7–2t中，一组特定的DEG参与了苯丙烷的生物合成和牛磺酸（hypotaurine）的代谢。这些DEG富含与膜系统和细胞壁生物合成相关的细胞成分。C7-2t的耐旱性主要是由于其高持水能力，稳定的光合作用（用于支持渗透调节）和在干旱条件下增强了细胞壁的生物合成。而C7–2t中的这些基因在干旱下几乎不受影响。此外，在C7–2t中，一组特定的DEG参与了苯丙烷的生物合成和牛磺酸（hypotaurine）的代谢。这些DEG富含与膜系统和细胞壁生物合成相关的细胞成分。C7-2t的耐旱性主要是由于其高持水能力，稳定的光合作用（用于支持渗透调节）和在干旱条件下增强了细胞壁的生物合成。