GIGANTEA-like genes control seasonal growth cessation in Populus

First author: Jihua Ding; Affiliations: Swedish University of Agricultural Sciences (瑞典农业科学大学): Umeå, Sweden

Corresponding author: Ove Nilsson

Survival of trees growing in temperate zones (温带) requires cycling between active growth and dormancy (休眠). This involves growth cessation (生长停止) in the autumn triggered by a photoperiod (光周期) shorter than the critical day length (临界日长). Variations in GIGANTEA (GI)-like genes have been associated with phenology (物候) in a range of different tree species, but characterization of the functions of these genes in the process is still lacking. We describe the identification of the Populus orthologs of GI and their critical role in short-day-induced growth cessation. Using ectopic expression (异位表达) and silencing, gene expression analysis, protein interaction and chromatin immunoprecipitation experiments, we show that PttGIs are likely to act in a complex with PttFKF1s (FLAVIN-BINDING, KELCH REPEAT, F-BOX 1) and PttCDFs (CYCLING DOF FACTOR) to control the expression of PttFT2, the key gene regulating short-day-induced growth cessation in Populus. In contrast to Arabidopsis, in which the GI-CONSTANS (CO)-FLOWERING LOCUS T (FT) regulon (调节子) is a crucial day-length sensor for flowering time, our study suggests that, in Populus, PttCO-independent regulation of PttFT2 by PttGI is more important in the photoperiodic control of growth cessation and bud set (驻芽).

林木在温带地区生长必需能够进行生长和休眠之间的循环。这需要林木在秋天能够被比临界日长更短的光周期所诱导进入生长中止。已知类GI基因在许多不同物种中与物候相关，但这些基因在这个过程中的功能研究还不多。本文鉴定了杨树的GI同源基因及其在短日照诱导的生长中止中的重要作用。利用异位表达和沉默、基因表达分析、蛋白互作及染色质免疫沉淀试验，本文的研究显示PttGIs可能与PttFKF1s和PttCDFs形成复合物以控制PttFT2基因的表达，而PttFT2基因是杨树中短日照诱导的生长中止关键基因。拟南芥中GI-CO-FT调控子对于感应短日照进而控制植物开花时间至关重要，而与拟南芥相反，杨树中不依赖于PttCO基因的PttGI调控PttFT2在光周期调控生长中止和驻芽更加重要。

通讯：Ove Nilsson (https://www.upsc.se/researchers/4643-control-of-flowering-time-and-meristem-identity-ove-nilsson.html#cv-dr-ove-nilsson)

个人简历：1987年，哥德堡大学，学士；1988年，于默奥大学，学士；1995年，瑞典农业科学大学，博士；1995年，美国索尔克生物研究所，博士后。

研究方向：利用模式植物拟南芥和杨树研究分生组织一致性和开花时间调控。

doi: 10.1111/nph.15087

Journal: New Phytologist

Published date: 13 March, 2018

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