与萱草（Hemerocallis fulva）花程序性细胞死亡相关的两个 NAC 转录因子 HfNAP1 和 HfNAC090 的功能特征。

Functional characterization of two NAC transcription factors HfNAP1 and HfNAC090 associated with flower programmed cell death in daylily (Hemerocallis fulva).

机构信息

Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing, China.

出版信息

Plant Sci. 2023 Dec;337:111872. doi: 10.1016/j.plantsci.2023.111872. Epub 2023 Sep 18.

DOI:10.1016/j.plantsci.2023.111872

PMID:37729968

Abstract

Daylily (Hemerocallis fulva) is one of the most widely used perennial flowers, but its ornamental and economic value is greatly limited due to its ephemeral flowering period. In general, the flower senescence is regulated by the developmental signals and considered as an irreversible process of programmed cell death (PCD). However, the molecular mechanism of flower PCD in daylily still remains unclear. In this study, two NAC transcription factors, namely HfNAP1 and HfNAC090, are first identified and found to be upregulated significantly in both the age-induced and the ABA-induced flower PCD processes in daylily. Then, the functions of HfNAP1 and HfNAC090 in regulating the flower PCD are investigated through transgenic phenotypes analysis. The results demonstrate that the ectopic and transient overexpression of these two genes can effectively regulate the flower PCD in tobacco and daylily. While the overexpression of HfNAP1 accelerates the flower PCD process, the overexpression of HfNAC090 significantly delays that. Furthermore, the yeast two-hybrid assay is performed to discover potential interactions related to these two genes, and the results demonstrate that HfNAP1 and HfNAC090 can interact with each other, or interact with other flower aging-related genes. Additionally, the yeast one-hybrid assay suggests that HfNAP1 and HfNAC090 can bind directly to the promoters of downstream senescence-associated genes HfSAG39 and HfSAG15. Taken overall, this study provides sufficient evidences to confirm that HfNAP1 and HfNAC090 play dominant roles in regulating the flower PCD in daylily, supporting the development of new strategies to prolong the longevity of daylily flowers.

摘要

萱草（Hemerocallis fulva）是最广泛使用的多年生花卉之一，但由于其短暂的开花期，其观赏和经济价值受到极大限制。一般来说，花的衰老受发育信号的调节，被认为是细胞程序性死亡（PCD）的不可逆过程。然而，萱草花 PCD 的分子机制仍不清楚。在本研究中，首次鉴定出两个 NAC 转录因子，即 HfNAP1 和 HfNAC090，并发现它们在萱草的年龄诱导和 ABA 诱导的花 PCD 过程中均显著上调。然后，通过转基因表型分析研究了 HfNAP1 和 HfNAC090 调节花 PCD 的功能。结果表明，这些基因的异位和瞬时过表达可以有效地调节烟草和萱草的花 PCD。而过表达 HfNAP1 加速了花 PCD 过程，而过表达 HfNAC090 则显著延迟了该过程。此外，进行了酵母双杂交实验以发现与这两个基因相关的潜在相互作用，结果表明 HfNAP1 和 HfNAC090 可以相互作用，或与其他与花衰老相关的基因相互作用。此外，酵母单杂交实验表明 HfNAP1 和 HfNAC090 可以直接结合到下游衰老相关基因 HfSAG39 和 HfSAG15 的启动子上。总的来说，本研究提供了充分的证据证实 HfNAP1 和 HfNAC090 在调节萱草花 PCD 中起主导作用，支持开发延长萱草花寿命的新策略。