中国农业科学 ›› 2022, Vol. 55 ›› Issue (20): 3875-3884.doi: 10.3864/j.issn.0578-1752.2022.20.001

• 作物遗传育种·种质资源·分子遗传学 • 上一篇    下一篇

FCS-Like锌指蛋白OsFLZ18在调控水稻抽穗期中的作用

马雅美(),张少红,赵均良(),刘斌()   

  1. 广东省农业科学院水稻研究所/广东省水稻育种新技术重点实验室/广东省水稻工程实验室,广州 510640
  • 收稿日期:2022-05-20 接受日期:2022-06-23 出版日期:2022-10-16 发布日期:2022-10-24
  • 通讯作者: 赵均良,刘斌
  • 作者简介:马雅美,E-mail: mayamei@gdaas.cn
  • 基金资助:
    广东省自然科学基金(2022A1515012361);广东省自然科学基金(2019A1515010003);广州市科技计划(202002030375);科技创新战略建设专项资金(高水平农科院建设)(R2021PY-QF001);广东省现代农业产业技术体系农业种业共性关键技术创新团队建设项目(2020KJ106);广东省现代农业产业技术体系农业种业共性关键技术创新团队建设项目(2021KJ106);广东省重点实验室运行费(2020B1212060047)

Function of FCS-Like Zinc-Finger Protein OsFLZ18 in Regulating Rice Flowering Time

MA YaMei(),ZHANG ShaoHong,ZHAO JunLiang(),LIU Bin()   

  1. Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640
  • Received:2022-05-20 Accepted:2022-06-23 Online:2022-10-16 Published:2022-10-24
  • Contact: JunLiang ZHAO,Bin LIU

摘要:

【目的】 抽穗期是水稻重要的农艺性状,适时抽穗是确保水稻产量和区域适应性的关键因素。然而,水稻抽穗期调控的基因及其调控网络仍需进一步研究。已知FCS-like锌指蛋白是植物特有且在植物生长发育和逆境响应过程中发挥重要作用的蛋白家族,但其调控植物开花的功能未知。研究OsFLZs在调控水稻抽穗期中的功能,有助于完善水稻抽穗期调控网络,同时为抽穗期遗传育种提供新的理论基础和基因资源。【方法】 根据RGAP数据库公布的基因序列,构建OsFLZ18的过量表达载体和CRISPR-Cas9敲除载体,通过农杆菌介导的遗传转化方法转化日本晴愈伤组织,从而获得相应的水稻转基因植株;利用PCR技术筛选并鉴定OsFLZ18敲除纯合株系;在水稻生长过程中,调查过量表达、敲除植株和日本晴植株的抽穗时间;采用qRT-PCR方法分析OsFLZ18的时空表达模式,昼夜节律性以及OsFLZ18对抽穗期调控基因表达的影响;通过酵母双杂交试验验证OsFLZ18与调控水稻抽穗期关键因子的相互作用。【结果】 OsFLZ18的表达无明显组织特异性,在14 d的幼苗中表达量最高,其次是分蘖期的叶鞘和叶片,以及生殖生长阶段的茎和幼穗;成功构建了OsFLZ18-CRISPR载体,并转入粳稻日本晴中,筛选并鉴定获得2个CRISPR敲除纯合突变体。采用表达量较高的2个OE植株(OE-2和OE-3)以及纯合的敲除植株(CRISPR-21和CRISPR-25)进行抽穗期表型观察。结果发现,在广州自然短日照和自然长日照条件下,OE植株均出现明显的晚花表型,但是CRISPR敲除植株的抽穗时间较野生型无明显差异。qRT-PCR结果表明,在人工短日照条件下,与野生型相比,OE-2植株中Ehd1Hd3aRFT1的表达量明显被抑制,但Hd1的表达量没有明显的变化。酵母双杂交试验表明OsFLZ18和正向调控水稻抽穗期的转录因子OsMADS51存在互作。同时,OsFLZ18的表达量存在昼夜节律性,在白天表达量低,夜晚表达量高,并在半夜达到最高值。【结论】 过量表达OsFLZ18可以导致水稻延迟抽穗。

关键词: 水稻, 抽穗期, FLZ, OsMADS51

Abstract:

【Objective】Flowering time is an important agronomic trait which determines the yield and regional adaptability of rice, but the underlining molecular regulatory mechanism need further study. FCS-like Zinc finger proteins (FLZs) are a class of plant specific regulatory proteins which play essential roles in plant growth and stress response, but their functions in regulating flowering time have not been reported. This study aims to investigate the potential function of FLZ proteins in rice flowering time control. The finding will broaden our understanding on the molecular regulatory mechanism of rice flowering time.and provide new theoretical basis and gene resource for rice breeding. 【Method】Based on the target sequences published in RGAP database, OsFLZ18 overexpression vector and CRISPR-Cas9 vector were generated and introduced into Japonica variety Nipponbare by Agrobacterium tumefaciens-mediated genetic transformation assay. Homozygous CRISPR knockout mutants were screened by PCR and sequencing analyses. The quantitative real-time PCR (qRT-PCR) assay was used to examine the spatial-temporal expression and diurnal rhythmic expression of OsFLZ18, as well as the effects of OsFLZ18 on the transcription of several known flowering time-related genes. Yeast two-hybrid assay (Y2H) was used to test the interaction between OsFLZ18 and the flowering time-related regulatory proteins.【Result】OsFLZ18 was ubiquitously expressed in various rice tissues, with the highest expression level in 14 day-old seedling, followed by leaf sheaths and leaf blades at the tillering stage, and stem and young panicles at reproductive stages. The OsFLZ18-CRISPR vector was constructed and transformed into Nipponbare. Two independent homozygous OE lines (OE-2, OE-3) with higher OsFLZ18 expression level and two homozygous mutants (CRISPR-21, CRISPR-25) were selected for further study. Phenotypic observation showed that the OE lines flowered later than the wild-type plants under both natural long-day and short-day conditions in Guangzhou, while the CRISPR lines had no obvious differences in heading date when compared to the wild-type plants. The expression levels of Ehd1, Hd3a and RFT1 were significantly decreased in OE-2 plants compared with those in the wild-type plants under artificial short-day conditions, but no significant difference in the expression level of Hd1 was observed between them. The results of Y2H experiment showed that OsFLZ18 interacted with OsMADS51, a positive regulator of rice flowering time. Furthermore, OsFLZ18 exhibits a diurnal rhythmic expression profile, showing lower expression levels in the daytime and higher expression levels at night with a peak at midnight. 【Conclusion】Overexpression of OsFLZ18 delays rice flowering time.

Key words: rice, flowering time, FLZ, OsMADS51