Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology Ministry of Education, Nanjing Forestry University, Nanjing 210037, China.
Willow Nursery of the Jiangsu Provincial Platform for Conservation and Utilization of Agricultural Germplasm, Jiangsu Academy of Forestry, Nanjing 211153, China.
Int J Mol Sci. 2023 Jul 12;24(14):11334. doi: 10.3390/ijms241411334.
The NAC (NAM-ATAF1/2-CUC) transcription factor family is one of the largest plant-specific transcription factor families, playing an important role in plant growth and development and abiotic stress response. As a short-rotation woody plant, () has high lead (Pb) phytoremediation potential. To understand the role of NAC in Pb tolerance, 53 transcripts were identified using third-generation and next-generation transcriptomic data from exposed to Pb stress, and a phylogenetic analysis revealed 11 subfamilies. A sequence alignment showed that multiple subfamilies represented by TIP and ATAF had a gene that produced more than one transcript under Pb stress, and different transcripts had different responses to Pb. By analyzing the expression profiles of at 9 Pb stress time points, 41 of 53 were found to be significantly responsive to Pb. Short time-series expression miner (STEM) analysis revealed that 41 had two significant Pb positive response patterns (early and late), both containing 10 . The with the most significant Pb response were mainly from the ATAF and NAP subfamilies. Therefore, 4 and 3 from the ATAF and NAP subfamilies, respectively, were selected as candidate Pb-responsive for further structural and functional analysis. The RT-qPCR results of 7 transcripts also confirmed the different Pb response patterns of the ATAF and NAP subfamilies. SiNAC004 and SiNAC120, which were randomly selected from two subfamilies, were confirmed to be nuclear localization proteins by subcellular localization experiments. Functional prediction analysis of the associated transcripts of seven candidate showed that the target pathways of ATAF subfamily SiNACs were "sulfur metabolism" and "glutathione metabolism", and the target pathways of NAP subfamily SiNACs were "ribosome" and "phenylpropanoid biosynthesis". This study not only identified two NAC subfamilies with different Pb response patterns but also identified Pb-responsive that could provide a basis for subsequent gene function verification.
NAC（NAM-ATAF1/2-CUC）转录因子家族是植物特有的最大转录因子家族之一，在植物生长发育和非生物胁迫响应中发挥重要作用。作为一种短轮伐期木本植物，()具有较高的铅（Pb）植物修复潜力。为了了解 NAC 在 Pb 耐受中的作用，使用来自 Pb 胁迫下的第三代和下一代转录组数据鉴定了 53 个转录本，系统发育分析揭示了 11 个子家族。序列比对表明，TIP 和 ATAF 代表的多个亚家族在 Pb 胁迫下产生了一个以上的转录本，并且不同的转录本对 Pb 的响应不同。通过分析 53 个在 9 个 Pb 胁迫时间点的表达谱，发现其中 41 个对 Pb 有明显响应。短时间序列表达挖掘器（STEM）分析显示，41 个转录本具有两种显著的 Pb 正响应模式（早期和晚期），均包含 10 个转录本。具有最显著 Pb 响应的转录本主要来自 ATAF 和 NAP 亚家族。因此，分别从 ATAF 和 NAP 亚家族中选择了 4 和 3 个作为候选的 Pb 响应转录本，用于进一步的结构和功能分析。7 个转录本的 RT-qPCR 结果也证实了 ATAF 和 NAP 亚家族的不同 Pb 响应模式。随机从两个亚家族中选择的 SiNAC004 和 SiNAC120 通过亚细胞定位实验证实为核定位蛋白。对 7 个候选 相关转录本的功能预测分析表明，ATAF 亚家族 SiNACs 的靶途径为“硫代谢”和“谷胱甘肽代谢”，NAP 亚家族 SiNACs 的靶途径为“核糖体”和“苯丙烷生物合成”。本研究不仅鉴定了具有不同 Pb 响应模式的两个 NAC 亚家族，还鉴定了 Pb 响应转录本，可为后续基因功能验证提供依据。
