Fruit‐dependent epigenetic regulation of flowering in Citrus

First author: Manuel Agustí; Affiliations: Universitat Politècnica de València (瓦伦西亚理工大学): Valencia, Spain

Corresponding author: Miguel A. Blázquez 

In many perennial plants, seasonal flowering is primarily controlled by environmental conditions, but in certain polycarpic plants, environmental signals are locally gated by the presence of developing fruits initiated in the previous season through an unknown mechanism. Polycarpy is defined as the ability of plants to undergo several rounds of reproduction during their life time, alternating vegetative and reproductive meristems in the same individual. To understand how fruits regulate flowering in polycarpic plants, we have focused on alternate bearing in Citrus trees that had been experimentally established as fully flowering or non flowering. We have found that the presence of the fruit causes epigenetic changes correlating with the induction of the CcMADS19 floral repressor, which prevents the activation of the floral promoter CiFT2 even in the presence of the floral inductive signals. In contrast, newly emerging shoots display an opposite epigenetic scenario associated with CcMADS19 repression, thereby allowing the activation of CiFT2 the following cold season.

在很多多年生植物中，季节性的开花主要是由环境条件控制的，但在某些多次结实的植物中，上个季节起始、目前正在发育中的果实会通过某种未知的机制抑制局部的环境信号。多次结实的植物定义为在其整个生命周期过程中会经历多次生殖，在同一个体中营养和生殖分生组织轮流交替出现。为了研究多次结实植物中果实是如何调控开花的，作者主要利用柑桔树大小年结果的特性，即一年完全开花，下一年完全不开花，交替出现。作者发现柑桔树结出果实会导致开花抑制子CcMADS19基因诱导相关的表观改变，而CcMADS19基因能够防止开花促进基因CiFT2的激活，这种抑制效果存在开花诱导信号的条件下仍然可发挥作用。相反，新形成的芽会导致一个完全相反的表观变化，抑制CcMADS19基因的表达， 从而使得CiFT2基因在冷季过后能够顺利激活。

通讯：Miguel A. Blázquez (http://www.ibmcp.upv.es/en/staff/mblazquezibmcpupves)

个人简介：1995年，马德里自治大学，博士。

研究方向：控制植物早期发育的信号转导。

doi: https://doi.org/10.1111/nph.16044

Journal: New Phytologist

First Published: July 05, 2019