miR156-SPLs Module Regulates Somatic Embryogenesis Induction in Citrus Callus

First author: Jian-Mei Long; Affiliations: Huazhong Agricultural University (华中农业大学): Wuhan, China

Corresponding author: Xiao-Meng Wu& Wen-Wu Guo

As a highly conserved plant miRNA, miR156 has been intensively investigated for its versatile (多功能的) roles in plant development. Herein we report a novel role of miR156 in regulating somatic embryogenesis (SE) of citrus, one of the most widely cultivated fruit crops in the world. SE is an important way of regeneration, but SE potential of the preserved citrus embryogenic callus always declined during long-term sub-culturing (继代), becoming a key obstacle (障碍) for citrus biotechnology. In our study, either overexpression of csi-miR156a or individual knock-down of the two target genes CsSPL3 and CsSPL14 significantly enhanced SE competence of citrus callus, indicating that the effect of miR156-SPLs module was established for the initial phases of SE induction. Biological processes that might promote SE in response to miR156 overexpression were explored by RNA-seq, mainly including hormone signaling pathways, stress response, DNA methylation and cell cycle. CsAKIN10 was identified to interact with CsSPL14. In this study, effect of miR156-SPLs module on SE potential enhancement was validated in in vitro callus system of citrus, the corresponding regulatory pathway was explored and discussed, which provides theoretical basis for improvement of plant SE competence.

作为植物中高度保守的小RNA，miR156已被证明在植物发育过程中发挥多方面的作用。本文报道了miR156在调控柑橘体胚发生过程中的作用，柑橘是世界上栽培最多的水果作物之一。体胚发生是再生的重要途径，然而柑橘胚性愈伤在长时间的继代过程中体胚发生潜力会不断下降，这已经成为了柑橘生物技术的主要障碍。在本文的研究中，无论过表达 csi-miR156a或者单独敲掉CsSPL3和CsSPL14均能够显著提升柑橘愈伤诱导出体胚的能力，显示miR156-SPLs模块在体胚发生诱导的初期发挥作用。作者通过RNA-seq对于miR156过表达促进体胚发生的生物学过程进行了探索，结果显示与激素信号途径、胁迫响应、DNA甲基化和细胞周期相关。经鉴定，CsAKIN10与CsSPL14互作。本文同时还通过柑橘体外的愈伤体系验证了miR156-SPLs模块对于体胚发生潜在的增强影响，并讨论了相应的调控通路，为植物体胚发生的能力提升提供理论基础。

通讯：郭文武 (http://hortilab.hzau.edu.cn/yjdw/cspi/yj1/201109/t20110927_12489.htm)

个人简介：1993年，华中农业大学，园艺系学士；1993-1998年，华中农业大学，硕士、博士；1998年，华中农业大学，讲师；1999年，华中农业大学，副教授；2001-2003年，美国佛罗里达大学，柑橘研究与教育中心博士后；2003年，华中农业大学，教授；2007年，澳大利亚CSIRO园艺部、澳大利亚国立大学，高级访问学者；2009年，日本鹿儿岛大学，高级访问学者。

研究方向：柑橘种质创新与遗传改良。1）体细胞胚 / 珠心胚发育的分子机理；2）细胞工程与种质创新：体细胞杂种 / 胞质杂种创制，倍性杂交结合幼胚挽救培养创制三倍体，同源多倍体发掘与利用，纯系创制，细胞工程新品种选育；3）细胞工程新种质特殊性状解析：胞质杂种雄性不育性状解析与基因发掘，同源 / 异源多倍体的遗传 / 表观遗传变异分析，分子育种。

doi: https://doi.org/10.1093/jxb/ery132

Journal: Journal of Experimental Botany

Published online: 05 April, 2018

（P.S. 欢迎关注微信公众号：微信号Plant_Frontiers）