Wang Shuang, Dong Liben, Yao Wenjing, Jiang Tingbo
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
Harbin Research Institute of Forestry Machinery, State Administration of Forestry and Grassland, Harbin 150086, China.
Plants (Basel). 2024 Jul 3;13(13):1835. doi: 10.3390/plants13131835.
The bHLH transcription factor family plays crucial roles in plant growth and development and their responses to adversity. In this study, a highly salt-induced bHLH gene, (Potri.018G141600), was identified from (84K poplar). PagbHLH35 contains a highly conserved bHLH domain within the region of 52-114 amino acids. A subcellular localization result confirmed its nuclear localization. A yeast two-hybrid assay indicated PagbHLH35 lacks transcriptional activation activity, while a yeast one-hybrid assay indicated it could specifically bind to G-box and E-box elements. The expression of reached its peak at 12 h and 36 h time points under salt stress in the leaves and roots, respectively. A total of three positive transgenic poplar lines overexpressing were generated via -mediated leaf disk transformation. Under NaCl stress, the transgenic poplars exhibited significantly enhanced morphological and physiological advantages such as higher POD activity, SOD activity, chlorophyll content, and proline content, and lower dehydration rate, MDA content and hydrogen peroxide (HO) content, compared to wild-type (WT) plants. In addition, histological staining showed that there was lower ROS accumulation in the transgenic poplars under salt stress. Moreover, the relative expression levels of several antioxidant genes in the transgenic poplars were significantly higher than those in the WT. All the results indicate that can improve salt tolerance by enhancing ROS scavenging in transgenic poplars.
bHLH转录因子家族在植物生长发育及其对逆境的响应中发挥着关键作用。在本研究中，从84K杨树中鉴定出一个高度盐诱导的bHLH基因（Potri.018G141600）。PagbHLH35在52 - 114个氨基酸区域内含有一个高度保守的bHLH结构域。亚细胞定位结果证实了其核定位。酵母双杂交试验表明PagbHLH35缺乏转录激活活性，而酵母单杂交试验表明它可以特异性结合G - box和E - box元件。在盐胁迫下，其在叶片和根中的表达分别在12小时和36小时时间点达到峰值。通过农杆菌介导的叶盘转化共获得了三个过表达PagbHLH35的阳性转基因杨树株系。在NaCl胁迫下，与野生型（WT）植株相比，转基因杨树表现出显著增强的形态和生理优势，如更高的POD活性、SOD活性、叶绿素含量和脯氨酸含量，以及更低的脱水率、MDA含量和过氧化氢（H₂O₂）含量。此外，组织化学染色表明盐胁迫下转基因杨树中ROS积累较低。而且，转基因杨树中几个抗氧化基因的相对表达水平显著高于野生型。所有结果表明PagbHLH35可以通过增强转基因杨树中的ROS清除来提高耐盐性。
