Ma Xiaoyan, Qiao Zhu, Chen Donghua, Yang Weiguo, Zhou Ruijia, Zhang Wei, Wang Mei
Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China.
Plant Mol Biol. 2015 Jun;88(3):287-99. doi: 10.1007/s11103-015-0324-z. Epub 2015 May 7.
Cyclin-dependent protein kinases are involved in many crucial cellular processes and aspects of plant growth and development, but their precise roles in abiotic stress responses are largely unknown. Here, Arabidopsis thaliana CYCLIN-DEPENDENT KINASE G2 (CDKG2) was shown to act as a negative regulator of the salinity stress response, as well as being involved in the control of flowering time. GUS expression experiments based on a pCDKG2::GUS transgene suggested that CDKG2 was expressed throughout plant development, with especially high expression levels recorded in the seed and in the flower. The loss-of-function of CDKG2 led to an increased tolerance of salinity stress and the up-regulation of the known stress-responsive genes SOS1, SOS2, SOS3, NHX3, RD29B, ABI2, ABI3, MYB15 and P5CS1. Flowering was accelerated in the cdkg2 mutants via the repression of FLC and the consequent up-regulation of FT, SOC1, AP1 and LFY. Transgenic lines constitutively expressing CDKG2 showed greater sensitivity to salinity stress and were delayed in flowering. Furthermore, the CDKG2 genotype affected the response of flowering time to salinity stress. Our data connect CDKG2 to undescribed functions related to salt stress tolerance and flowering time through the regulation of specific target genes.
细胞周期蛋白依赖性蛋白激酶参与许多关键的细胞过程以及植物生长发育的多个方面，但其在非生物胁迫响应中的精确作用在很大程度上尚不清楚。在此，拟南芥细胞周期蛋白依赖性激酶G2（CDKG2）被证明是盐胁迫响应的负调控因子，并且参与开花时间的控制。基于pCDKG2::GUS转基因的GUS表达实验表明，CDKG2在植物整个发育过程中均有表达，在种子和花中记录到的表达水平尤其高。CDKG2功能缺失导致对盐胁迫的耐受性增强，以及已知的胁迫响应基因SOS1、SOS2、SOS3、NHX3、RD29B、ABI2、ABI3、MYB15和P5CS1的上调。通过抑制FLC以及随后上调FT、SOC1、AP1和LFY，cdkg2突变体的开花加速。组成型表达CDKG2的转基因株系对盐胁迫表现出更高的敏感性，并且开花延迟。此外，CDKG2基因型影响开花时间对盐胁迫的响应。我们的数据通过调控特定靶基因，将CDKG2与与耐盐性和开花时间相关的未描述功能联系起来。
