College of Life Sciences, National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou, China.
BMC Plant Biol. 2020 Jul 3;20(1):315. doi: 10.1186/s12870-020-02526-w.
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 Co-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.
频繁发生的干旱胁迫对全球范围内的玉米生产产生负面影响。人们已经做出了许多努力来开发耐旱玉米品系，并探索玉米的耐旱机制。然而，对于耐旱和对照玉米品系之间的转录组变化，缺乏比较研究。
在本研究中，我们通过用 Co-γ 辐照玉米自交系 ChangC7-2（C7-2）的种子，培育出了一个耐旱的玉米突变体（C7-2t）。与野生型 C7-2 相比，C7-2t 在受控和田间条件下表现出明显的延迟萎蔫和更高的耐旱性，表明其具有较高的持水能力。进行了转录组谱分析，以鉴定 C7-2 和 C7-2t 在干旱条件下的差异表达基因（DEGs）。结果表明，共有 4552 个 DEGs 参与了 C7-2 和 C7-2t 的耐旱性。特别是，C7-2 中与光合作用相关的基因表达受到抑制，而 C7-2t 中的这些基因在干旱下几乎不受影响。此外，一组特定的 DEGs 参与了 C7-2t 中的苯丙烷生物合成和牛磺酸（次牛磺酸）代谢；这些 DEGs在与膜系统和细胞壁生物合成相关的细胞成分中富集。
C7-2t 的耐旱性主要归因于其高持水能力、稳定的光合作用（支持渗透调节）和在干旱条件下增强细胞壁的生物合成。
