College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, Jiangsu, China.
J Exp Bot. 2021 Feb 24;72(4):1399-1410. doi: 10.1093/jxb/eraa507.
Drought stress severely limits the growth, development, and productivity of crops, and therefore understanding the mechanisms by which plants respond to drought is crucial. In this study, we cloned a maize NAC transcription factor, ZmNAC49, and identified its function in response to drought stress. We found that ZmNAC49 is localized in the nucleus and has transcriptional activation activity. ZmNAC49 expression is rapidly and strongly induced by drought stress, and overexpression enhances stress tolerance in maize. Overexpression also significant decreases the transpiration rate, stomatal conductance, and stomatal density in maize. Detailed study showed that ZmNAC49 overexpression affects the expression of genes related to stomatal development, namely ZmTMM, ZmSDD1, ZmMUTE, and ZmFAMA. In addition, we found that ZmNAC49 can directly bind to the promoter of ZmMUTE and suppress its expression. Taken together, our results show that the transcription factor ZmNAC49 represses ZmMUTE expression, reduces stomatal density, and thereby enhances drought tolerance in maize.
干旱胁迫严重限制了作物的生长、发育和生产力，因此了解植物对干旱的响应机制至关重要。在这项研究中，我们克隆了一个玉米 NAC 转录因子 ZmNAC49，并鉴定了它在应对干旱胁迫中的功能。我们发现 ZmNAC49 定位于细胞核，具有转录激活活性。干旱胁迫可快速且强烈诱导 ZmNAC49 的表达，过表达可增强玉米的胁迫耐受性。过表达还可显著降低玉米的蒸腾速率、气孔导度和气孔密度。详细研究表明，ZmNAC49 过表达影响与气孔发育相关的基因的表达，即 ZmTMM、ZmSDD1、ZmMUTE 和 ZmFAMA。此外，我们发现 ZmNAC49 可以直接结合 ZmMUTE 启动子并抑制其表达。综上所述，我们的结果表明，转录因子 ZmNAC49 抑制 ZmMUTE 的表达，降低气孔密度，从而增强玉米的耐旱性。
