Hughes Ariel M, Zwack Paul J, Cobine Paul A, Rashotte Aaron M
Department of Biological Sciences Auburn University Auburn AL USA.
Plant Direct. 2020 Dec 8;4(12):e00291. doi: 10.1002/pld3.291. eCollection 2020 Dec.
Cytokinin (CK) is a plant hormone crucial to plant development and growth. Cytokinin Response Factor 6 (CRF6) is a CK-induced transcription factor that is part of the CK signaling cascade. While the role of CRF6 has been examined in oxidative stress response, there has been surprisingly little investigation of CRF6 in the context of CK signaling, including identifying CK-regulated targets of CRF6. Here, we conduct a transcriptomic study of Arabidopsis examining the CRF6 mutant () in the presence and absence of CK, revealing 163 downstream CRF6-dependent CK-regulated differentially expressed genes (DEGs). 15.3% of these DEGS were found as overlapping with larger number of standardly identified CK-regulated DEGs, suggesting that CRF6 is involved in regulating a subset of downstream CK responses through these gene targets. The general transcriptional regulation of CRF6-dependent CK-regulated DEGs indicates that CRF6 may function as a negative regulator of CK response. We investigated one subset of CRF6 CK-dependent targets (, and ) involved in an underexamined functional role of CK response: the uptake and transportation of potassium. To determine how CK and CRF6 are involved in potassium acquisition and distribution, ionomic and physiological experiments were conducted on plants grown in media with sufficient and deficient potassium concentrations and in the presence and absence of CK. In order to investigate how CK alone affects potassium transport, similar experiments were performed on and mutant lines of these CRF6-dependent CK-regulated targets. These findings indicate novel connections between CK and potassium transport, which appear to be regulated in a CRF6-dependent manner.
细胞分裂素（CK）是一种对植物发育和生长至关重要的植物激素。细胞分裂素响应因子6（CRF6）是一种由CK诱导的转录因子，是CK信号级联反应的一部分。虽然已经研究了CRF6在氧化应激反应中的作用，但令人惊讶的是，在CK信号传导的背景下，对CRF6的研究很少，包括确定CRF6的CK调节靶标。在这里，我们对拟南芥进行了一项转录组学研究，检测了存在和不存在CK时的CRF6突变体（），揭示了163个下游CRF6依赖性CK调节的差异表达基因（DEG）。发现这些DEG中有15.3%与大量标准鉴定的CK调节的DEG重叠，这表明CRF6通过这些基因靶标参与调节下游CK反应的一个子集。CRF6依赖性CK调节的DEG的一般转录调控表明，CRF6可能作为CK反应的负调节因子发挥作用。我们研究了CRF6 CK依赖性靶标的一个子集（、和），它们参与了CK反应中一个研究不足的功能作用：钾的吸收和运输。为了确定CK和CRF6如何参与钾的获取和分配，对在钾浓度充足和不足的培养基中生长且存在和不存在CK的植物进行了离子组学和生理学实验。为了研究单独的CK如何影响钾的运输，对这些CRF6依赖性CK调节靶标的和突变体品系进行了类似的实验。这些发现表明CK与钾运输之间存在新的联系，它们似乎以CRF6依赖性方式受到调节。
