Chen Zhiwei, Huang Jianhua, Muttucumaru Nira, Powers Stephen J, Halford Nigel G
Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Road, Minhang District, Shanghai 201106, Peoples' Republic of China.
Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom.
J Cereal Sci. 2013 Sep;58(2):255-262. doi: 10.1016/j.jcs.2013.06.009.
The expression of genes encoding components of ABA and metabolic signalling pathways in developing barley endosperm and embryo was investigated. The genes included and (encoding ABA receptors), (protein phosphatase 2C), , and (SnRK2-type protein kinases) and (ABA response element binding protein; AREBP), as well as two genes encoding SnRK1-type protein kinases. Both SnRK1 and SnRK2 phosphorylate AREBPs, but SnRK2 is activated by ABA whereas SnRK1 may be broken down. Multiple cereal AREBPs with two conserved SnRK1/2 target sites and another class of BZIP transcription factors with SnRK1/2 binding sites, including HvBLZ1, were identified. Barley grain (cv. Triumph) was sampled at 15, 20, 25 and 30 days post-anthesis (dpa). , , and were expressed highly in the endosperm but at much lower levels in the embryo. Conversely, and were expressed at higher levels in the embryo than the endosperm, while was expressed at similar levels in both. , , and all peaked in expression in the endosperm at 20 dpa. A model is proposed in which ABA brings about a transition from a SnRK1-dominated state in the endosperm during grain filling to a SnRK2-dominated state during maturation.
研究了发育中的大麦胚乳和胚中编码脱落酸（ABA）及代谢信号通路组分的基因表达情况。这些基因包括PYL1和PYL4（编码ABA受体）、PP2C（蛋白磷酸酶2C）、SnRK2.2、SnRK2.3和SnRK2.6（SnRK2型蛋白激酶）以及AREB1（ABA反应元件结合蛋白），还有两个编码SnRK1型蛋白激酶的基因。SnRK1和SnRK2都能使AREBPs磷酸化，但SnRK2被ABA激活，而SnRK1可能会被分解。已鉴定出多个具有两个保守SnRK1/2靶位点的谷物AREBPs以及另一类具有SnRK1/2结合位点的BZIP转录因子，包括HvBLZ1。在开花后15、20、25和30天（dpa）采集大麦籽粒（品种Triumph）。PYL1、PYL4、PP2C和SnRK2.6在胚乳中高表达，但在胚中的表达水平低得多。相反，SnRK2.2和SnRK2.3在胚中的表达水平高于胚乳，而AREB1在两者中的表达水平相似。PYL1、PYL4、PP2C和SnRK2.6在胚乳中的表达均在20 dpa时达到峰值。提出了一个模型，其中ABA导致从灌浆期胚乳中以SnRK1为主导的状态转变为成熟期以SnRK2为主导的状态。
