Key Laboratory of Forest Silviculture and Conservation of the Ministry of Education, Beijing Forestry University, Beijing, 100083, People's Republic of China.
Plant Mol Biol. 2018 Dec;98(6):471-493. doi: 10.1007/s11103-018-0792-z. Epub 2018 Nov 7.
Picea wilsonii transcription factor PwNAC2 enhanced plant tolerance to salt and drought stress through multiple signaling pathway and interacted with PwRFCP1 to participate in flowering regulation. NAC is one of the largest transcription factor families in plants, however, its role is not yet fully understood. Here, we identified a transcription factor PwNAC2 in Picea wilsonii, which localized in nucleus with transcriptional activity in C-terminal region and can form homodimer by itself. Expression analysis by real-time PCR showed that PwNAC2 was induced by multiple abiotic stresses and phytohormones stimuli. PwRFCP1 (Resemble-FCA-contain-PAT1 domain), an interaction protein of PwNAC2 was screened via yeast two hybrid. Luciferase complementation assay confirmed the interaction in vivo and bimolecular fluorescence complementation assay showed the interaction in nucleus. PwNAC2 overexpression retarded Arabidopsis hypocotyls growth which is closely related to light, whereas promotion of hypocotyls growth by PwRFCP1 is independent on light. Under drought or salt treatment, overexpression of PwNAC2 in Arabidopsis showed more vigorous seed germination and significant tolerance for seedlings by ROS scavenging, reducing of membrane damage, slower water loss and increased stomatal closure. ABA or CBF-pathway marker genes were substantially higher in PwNAC2 transgenic Arabidopsis. Overexpression of PwRFCP1 promotes flowering in transgenic Arabidopsis, whereas PwNAC2 delayed flowering by altering the expression of FT, SOC1 and FLC. In addtioin, PwRFCP1 overexpression plants showed no higher tolerance to stress treatment than Col-0. Collectively, our results indicate that PwNAC2 enhanced plant tolerance to abiotic stress through multiple signaling pathways and participated in PwRFCP1-regulated flowering time.
云杉转录因子 PwNAC2 通过多条信号通路增强植物对盐和干旱胁迫的耐受性，并与 PwRFCP1 相互作用参与开花调控。NAC 是植物中最大的转录因子家族之一，但其作用尚未完全阐明。在这里，我们在云杉中鉴定了一个转录因子 PwNAC2，它定位于细胞核内，在 C 端区域具有转录活性，并且可以自身形成同源二聚体。实时 PCR 表达分析表明，PwNAC2 受多种非生物胁迫和植物激素刺激诱导。通过酵母双杂交筛选到 PwNAC2 的互作蛋白 PwRFCP1（Resemble-FCA-contain-PAT1 domain）。荧光素酶互补实验在体内证实了互作，双分子荧光互补实验显示互作发生在细胞核内。PwNAC2 过表达延缓拟南芥下胚轴生长，这与光密切相关，而 PwRFCP1 促进下胚轴生长不依赖于光。在干旱或盐胁迫下，PwNAC2 过表达的拟南芥种子表现出更强的萌发活力和对幼苗的显著耐受性，通过清除 ROS、减少膜损伤、减缓水分流失和增加气孔关闭来实现。PwNAC2 转基因拟南芥中 ABA 或 CBF 途径标记基因显著升高。PwRFCP1 过表达促进转基因拟南芥开花，而 PwNAC2 通过改变 FT、SOC1 和 FLC 的表达来延迟开花。此外，PwRFCP1 过表达植株在胁迫处理下的耐受性并不高于 Col-0。总之，我们的结果表明，PwNAC2 通过多条信号通路增强植物对非生物胁迫的耐受性，并参与 PwRFCP1 调控的开花时间。
