HISTONE DEACETYLASE 19 and the flowering time gene FD maintain reproductive meristem identity in an age-dependent manner

First author: Sasha R Gorham; Affiliations: American University (美利坚大学): Washington D.C., USA

Corresponding author: Naden T Krogan

The shoot apical meristem (SAM; 茎尖分生组织) undergoes developmental transitions that include a shift from vegetative to reproductive growth. This transition is triggered by flowering time genes, which up-regulate floral meristem (FM) identity genes that, in turn, control flower development by activating floral organ identity genes. This cascade of transcriptional activation is refined by repression mechanisms that temporally and spatially restrict gene expression to ensure proper development. Here, we demonstrate that HISTONE DEACETYLASE 19 (HDA19) maintains the identity of the reproductive SAM, or inflorescence meristem (IM), late in Arabidopsis thaliana development. At late stages of growth, hda19 IMs display a striking patterning defect characterized by ectopic expression of floral organ identity genes and the replacement of flowers with individual stamenoid organs (雄蕊器官). We further show that the flowering time gene FD has a specific function in this regulatory process, as fd hastens (加速) the emergence of these patterning defects in hda19 growth. Our work therefore identifies a new role for FD in reproductive patterning, as FD regulates IM function together with HDA19 in an age-dependent fashion. To effect these abnormalities (异常), hda19 and fd may accentuate (强调) the weakening of transcriptional repression that occurs naturally with reproductive meristem proliferation.

茎尖分生组织SAM会经历从营养生长到生殖生长的发育转变。该转变有开花时间基因触发，开花时间基因上调花分生组织决定基因，进而通过激活花器官决定基因控制花的发育。该转录激活级联受时空限制基因表达的抑制机制精确调控以保证发育过程的顺利进行。本文的研究揭示了组蛋白去乙酰化酶HDA19基因在拟南芥发育后期维持生殖SAM或者花序分生组织的特性。在拟南芥发育后期，hda19突变体的花序分生组织显示出明显的发育缺陷，包括花器官决定基因的异位表达以及完整的花器官变为单独的雄蕊器官。作者进一步的研究显示开花时间基因FD在调控过程中发挥了特殊的作用，fd突变体加速了hda19突变体发育缺陷的出现。本文的研究鉴定了FD基因在生殖器官发育中的新的作用，即FD基因与HDA19基因通过年龄依赖的方式共同调控花序分生组织的功能。这些突变体异常性状的产生可能是hda19和fd突变削弱了原本自然发生的生殖分生组织扩增过程中的转录抑制。

通讯：Naden T Krogan (https://www.american.edu/cas/faculty/nkrogan.cfm)

个人简介：加拿大里贾纳大学，生物学学士；加拿大里贾纳生物大学，理学硕士；加拿大多伦多大学，植物学与发育生物学博士。

研究方向：拟南芥中花器官形成和干细胞功能的转录调控研究。

doi: https://doi.org/10.1093/jxb/ery239

Journal: Journal of Experimental Botany

Published date: 11 July, 2018

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