Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland.
Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
Int J Mol Sci. 2020 Dec 2;21(23):9197. doi: 10.3390/ijms21239197.
The levels of methionine sulfoxide (MetO) and the abundances of methionine sulfoxide reductases (Msrs) were reported as important for the desiccation tolerance of seeds. To determine whether the MetO/Msrs system is related to reactive oxygen species (ROS) and involved in the regulation of germination in orthodox and recalcitrant seeds, Norway maple and sycamore were investigated. Changes in water content, MetO content, the abundance of MsrB1 and MsrB2 in relation to ROS content and the activity of reductases depending on nicotinamide adenine dinucleotides were monitored. seeds differed in germination speed-substantially higher in sycamore-hydration dynamics, levels of hydrogen peroxide, superoxide anion radicals (O) and hydroxyl radicals (•OH), which exhibited peaks at different stages of germination. The MetO level dynamically changed, particularly in sycamore embryonic axes, where it was positively correlated with the levels of O and the abundance of MsrB1 and negatively with the levels of •OH and the abundance of MsrB2. The MsrB2 abundance increased upon sycamore germination; in contrast, it markedly decreased in Norway maple. We propose that the ROS-MetO-Msr redox system, allowing balanced Met redox homeostasis, participates in the germination process in sycamore, which is characterized by a much higher speed compared to Norway maple.
甲硫氨酸亚砜（MetO）的水平和甲硫氨酸亚砜还原酶（Msr）的丰度被报道为种子耐旱性的重要因素。为了确定 MetO/Msrs 系统是否与活性氧（ROS）有关，并参与调控正常型和顽拗型种子的萌发，对挪威枫和美国梧桐进行了研究。监测了与 ROS 含量和还原酶活性有关的水含量、MetO 含量、MsrB1 和 MsrB2 的丰度变化，这些还原酶依赖于烟酰胺腺嘌呤二核苷酸。种子在萌发速度上存在差异——美国梧桐的萌发速度要快得多——水合动力学、过氧化氢、超氧阴离子自由基（O）和羟自由基（•OH）水平存在差异，这些自由基在萌发的不同阶段呈现出峰值。MetO 水平动态变化，特别是在美桐胚胎轴中，它与 O 的水平和 MsrB1 的丰度呈正相关，与•OH 的水平和 MsrB2 的丰度呈负相关。MsrB2 的丰度在美桐萌发时增加；相比之下，在挪威枫中则明显减少。我们提出，ROS-MetO-Msr 氧化还原系统，允许平衡 Met 氧化还原稳态，参与了美桐的萌发过程，其萌发速度比挪威枫要快得多。
