Plant Breeding and Acclimatization Institute-National Research Institute, 05-870 Błonie, Poland.
Int J Mol Sci. 2021 Dec 17;22(24):13572. doi: 10.3390/ijms222413572.
Brassinosteroids (BRs) control many plant developmental processes by regulating different groups of transcription factors, and consequently gene expressions. The most known is BZR1, the main member of the BES1 family. However, to date, it is poorly characterized in crop species. The main goal of the presented study was to identify BZR1 and determine its activity in 5-day-old barley (the stage is related to one leaf on the main shoot and a few seminal roots) using two cultivars with different sensitivities to BRs. Using the anti-BZR1 antibody, we identified the forms of BZR1 transcription factor with different molecular weights, which can be related to different phosphorylated forms of serine/threonine residues. Two phosphorylated forms in the shoots and one dephosphorylated form in the roots were determined. A minor amount of the dephosphorylated form of the BZR1 in the Haruna Nijo shoots was also found. The phosphorylated forms gave a higher band intensity for Golden Promise than Haruna Nijo. The bands were similar in their intensity, when two different phosphorylated forms were compared in Golden Promise, while a reduced intensity was detected for the phosphorylated form with a lower molecular weight for Haruna Nijo. Degradation of the phosphorylated forms in the shoots (complete degradation in Golden Promise and significant but not complete in Haruna Nijo) and the presence of the dephosphorylated form in the roots were proven for the etiolated barley. In the case of Haruna Nijo, a wider range of the regulators of the BR biosynthesis and signaling pathways induced the expected effects, 24-EBL (0.001 µM) and bikinin (10 and 50 µM) caused low amount of the phosphorylated forms, and at the same time, a tiny band of dephosphorylated form was detected. However, the expression of genes related to the BR biosynthesis and signaling pathways was not a determinant for the protein amount.
油菜素内酯 (BRs) 通过调节不同转录因子组，从而影响基因表达，来控制许多植物的发育过程。其中最为人熟知的是 BZR1，它是 BES1 家族的主要成员。然而，到目前为止，它在作物物种中的特征还描述得不够清楚。本研究的主要目标是鉴定 BZR1，并使用对 BR 具有不同敏感性的两种品种确定其在 5 天大的大麦（此时主茎上有一叶和几根初生根）中的活性。我们使用抗 BZR1 抗体鉴定了具有不同分子量的 BZR1 转录因子形式，这些形式可能与丝氨酸/苏氨酸残基的不同磷酸化形式有关。在茎中确定了两种磷酸化形式和一种去磷酸化形式，在根中确定了一种去磷酸化形式。在 Haruna Nijo 茎中还发现了少量的 BZR1 去磷酸化形式。与 Haruna Nijo 相比，磷酸化形式在 Golden Promise 中给出了更高的带强度。当在 Golden Promise 中比较两种不同的磷酸化形式时，这些带的强度相似，而在 Haruna Nijo 中，检测到磷酸化形式的强度降低，分子量较小。在暗培养的大麦中，证明了磷酸化形式在茎中的降解（在 Golden Promise 中完全降解，在 Haruna Nijo 中显著但不完全降解）和去磷酸化形式在根中的存在。在 Haruna Nijo 的情况下，BR 生物合成和信号转导途径的更多调节剂诱导了预期的效果，24-EBL（0.001 µM）和 bikinin（10 和 50 µM）导致低量的磷酸化形式，同时检测到微小的去磷酸化形式带。然而，与 BR 生物合成和信号转导途径相关的基因的表达不是蛋白质数量的决定因素。
