PDF(Pubmed)
Abstract：
The GhNAC2 transcription factor identified from G. herbaceum improves root growth and drought tolerance through transcriptional reprogramming of phytohormone signaling. The promoter of such a versatile gene could serve as an important genetic engineering tool for biotechnological application. In this study, we identified and characterized the promoter of GhNAC2 to understand its regulatory mechanism. GhNAC2 transcription factor increased in root tissues in response to GA, ethylene, auxin, ABA, mannitol, and NaCl. In silico analysis revealed an overrepresentation of cis-regulatory elements associated with hormone signaling, stress responses and root-, pollen-, and seed-specific promoter activity. To validate their role in GhNAC2 function/regulation, an 870-bp upstream regulatory sequence was fused with the GUS reporter gene (uidA) and expressed in Arabidopsis and cotton hairy roots for in planta characterization. Histochemical GUS staining indicated localized expression in root tips, root elongation zone, root primordia, and reproductive tissues under optimal growth conditions. Mannitol, NaCl, auxin, GA, and ABA, induced the promoter-driven GUS expression in all tissues while ethylene suppressed the promoter activity. The results show that the 870 nt fragment of the GhNAC2 promoter drives root-preferential expression and responds to phytohormonal and stress signals. In corroboration with promoter regulation, GA and ethylene pathways differentially regulated root growth in GhNAC2-expressing Arabidopsis. The findings suggest that differential promoter activity governs the expression of GhNAC2 in root growth and stress-related functions independently through specific promoter elements. This multifarious promoter can be utilized to develop yield and climate resilience in cotton by expanding the options to control gene regulation.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s12298-024-01411-2.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s12298-024-01411-2.
摘要：
从甘草酵母中鉴定的GhNAC2转录因子通过植物激素信号的转录重编程改善根生长和耐旱性。这种多功能基因的启动子可以作为生物技术应用的重要基因工程工具。在这项研究中,我们鉴定并鉴定了GhNAC2的启动子以了解其调控机制。GhNAC2转录因子在根组织中响应GA而增加，乙烯,生长素,ABA,甘露醇,和NaCl。计算机模拟分析显示，与激素信号相关的顺式调节元件过度表达，应激反应和根-，花粉-,和种子特异性启动子活性。为了验证它们在GhNAC2功能/调节中的作用，将870bp的上游调控序列与GUS报告基因（uidA）融合，并在拟南芥和棉花毛状根中表达，用于植物鉴定。组织化学GUS染色显示根尖局部表达，根伸长区，根原基，和生殖组织在最佳生长条件下。甘露醇,NaCl,生长素,GA,ABA,在所有组织中诱导启动子驱动的GUS表达，而乙烯抑制启动子活性。结果表明，GhNAC2启动子的870nt片段驱动根优先表达并响应植物激素和胁迫信号。在启动子调控的佐证中，GA和乙烯途径在表达GhNAC2的拟南芥中差异调节根的生长。研究结果表明，差异启动子活性通过特定的启动子元件独立地控制GhNAC2在根生长和胁迫相关功能中的表达。通过扩展控制基因调控的选择，可以利用这种多样化的启动子来发展棉花的产量和气候适应力。
■在线版本包含补充材料，可在10.1007/s12298-024-01411-2获得。
■在线版本包含补充材料，可在10.1007/s12298-024-01411-2获得。
