Russian Academy of Sciences, Institute of Basic Biological Problems, Institutskaya Street 2, Pushchino, Moscow 142290, Russia.
Russian Academy of Sciences, Institute of Basic Biological Problems, Institutskaya Street 2, Pushchino, Moscow 142290, Russia; Russian Academy of Sciences, Timiryazev Institute of Plant Physiology, Botanicheskaya Street 35, Moscow 127276, Russia.
J Photochem Photobiol B. 2019 May;194:14-20. doi: 10.1016/j.jphotobiol.2019.02.003. Epub 2019 Feb 18.
The effect of UV-B irradiation on the photosystem II (PSII) activity, the content of photosynthetic and UV-absorbing pigments (UAPs), activity of antioxidant enzymes such as catalase (CAT) and peroxidase (POD), as well as HO content in 25-day-old wild type (WT) and the cryptochrome 1 (Cry1) mutant hy4 of Arabidopsis thaliana Col-0 plants was studied. In addition, expression of photoreceptor genes Cry1, Cry2 and UVR8, photomorphogenetic gene COP1 and transcription factors genes HY5, HYH, the gene of chlorophyll-binding protein of the PSII CAB1 as well as the flavonoid biosynthesis genes CHS, PAL and thylakoid ascorbate peroxidase gene tAPX was examined. It has been shown that UV-B leads to a decrease in the photochemical activity of PSII (F/F) and the PSII performance index (PI) of WT plants grown on white (WL) and red (RL) light and also hy4 mutants grown on WL, RL and blue light (BL). In plants grown on BL and WL, the decrease in the PSII photochemical activity was significantly greater in hy4 compared to WT. The PSII of WT plants grown in BL was resistant to UV-B. The UAPs content of hy4 grown on BL and WL was lower than that in WT. The POD and CAT activities of WT grown in BL were significantly higher than in the mutant. In WT and hy4 plants grown in RL, a noticeable difference in these enzymes activity was not found. In both types of plants grown in BL and RL, the expression of photomorphogenetic genes HYH, HY5 markedly increased after UV-B treatment but the expression of the UV-B photoreceptor gene UVR8 was reduced in hy4 grown in BL and RL. It is assumed that reduced resistance of PSII in hy4 plants grown in BL and WL can be associated with low UAPs content as well as lowered POD and CAT activities. In addition, we suggest the lowered expression of UVR8 and COP1 genes caused by Cry1 deficiency leads to a shift of balance of oxidants and antioxidants towards oxidants.
研究了 25 天大的拟南芥野生型（WT）和隐花色素 1（Cry1）突变体 hy4 中 UV-B 辐射对光系统 II（PSII）活性、光合和 UV 吸收色素（UAP）含量、过氧化氢酶（CAT）和过氧化物酶（POD）等抗氧化酶活性以及 HO 含量的影响。此外，还检测了光受体基因 Cry1、Cry2 和 UVR8、光形态建成基因 COP1 和转录因子基因 HY5、HYH、PSII CAB1 叶绿素结合蛋白基因以及类黄酮生物合成基因 CHS、PAL 和类囊体抗坏血酸过氧化物酶基因 tAPX 的表达。结果表明，UV-B 导致在白光（WL）和红光（RL）下生长的 WT 植物和在 WL、RL 和蓝光（BL）下生长的 hy4 突变体的 PSII 光化学活性（F/F）和 PSII 性能指数（PI）降低。在 BL 和 WL 下生长的植物中，与 WT 相比，hy4 中 PSII 光化学活性的降低更为明显。在 BL 下生长的 WT 植物的 PSII 对 UV-B 具有抗性。在 BL 和 WL 下生长的 hy4 的 UAPs 含量低于 WT。在 BL 下生长的 WT 的 POD 和 CAT 活性明显高于突变体。在 RL 下生长的 WT 和 hy4 植物中，这些酶活性没有明显差异。在 BL 和 RL 下生长的两种类型的植物中，UV-B 处理后，光形态建成基因 HYH、HY5 的表达显著增加，但在 BL 和 RL 下生长的 hy4 中 UV-B 光受体基因 UVR8 的表达降低。我们假设 BL 和 WL 下生长的 hy4 植物 PSII 抗性降低可能与 UAPs 含量低以及 POD 和 CAT 活性降低有关。此外，我们认为 Cry1 缺乏导致 UV-B 光受体基因 UVR8 和 COP1 基因表达降低，导致氧化剂和抗氧化剂之间的平衡向氧化剂转移。
