Ningbo First Hospital, Ningbo, China ; College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University, State Key Laboratory of Crop Genetics & Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P.R. China.
PLoS One. 2013 Dec 12;8(12):e81470. doi: 10.1371/journal.pone.0081470. eCollection 2013.
Greening of etiolated plants is predominantly stimulated by light but the complete molecular mechanism is still unknown. Multiple studies currently focus on the important physiological effects of heme oxygenase (HO)/carbon monoxide (CO) in plants. In this report, firstly, the role of HO/CO in light-induced de-etiolation process was investigated. We discovered that light could significantly increase HO activities, HO-1 gene expression, CO release, and chlorophyll accumulation, all of which were sensitive to zinc protoporphyrin (ZnPPIX), the potent inhibitor of HO-1, respectively. Both HO-1 inducer hematin (H) and CO aqueous solution were able to relieve etiolation in wheat seedling leaves under completely darkness by up-regulating endogenous HO/CO system, so as nitric oxide (NO) donor sodium nitroprusside (SNP) did. Similarly, endogenous NO production was also boost in response to light, SNP, hematin and CO aqueous solution in wheat seedling leaves. Additionally, the restoration of chlorophyll contents was blocked, when the inhibitor of mammalian nitric oxide synthase N(G)-nitro-L-arginine methylester hydrochloride (L-NAME) or the specific scavenger of NO 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO) was added, respectively. Furthermore, the inducible effects of light were different from those of SNP, hematin, and CO on Pfr accumulation and PHYA transcripts. However, all of sodium nitroprusside (SNP), hematin, and CO could accelerate NO emission, which suggested that HO/CO in wheat seedlings de-etiolation under dark-light transition may have a cross talk with NO.
植物黄化后的变绿主要受光刺激，但完整的分子机制尚不清楚。目前多项研究集中于血红素加氧酶（HO）/一氧化碳（CO）在植物中的重要生理效应。在本报告中，首先研究了 HO/CO 在光诱导去黄化过程中的作用。我们发现，光照能显著提高 HO 活性、HO-1 基因表达、CO 释放和叶绿素积累，这些都对 HO-1 的强效抑制剂锌原卟啉（ZnPPIX）敏感。HO-1 诱导剂血红素（H）和 CO 水溶液均可在完全黑暗条件下通过上调内源性 HO/CO 系统来缓解小麦幼苗叶片的黄化，一氧化氮（NO）供体硝普钠（SNP）也有此作用。同样，NO 产生也会响应光照、SNP、血红素和 CO 水溶液而增加，在小麦幼苗叶片中。此外，当添加哺乳动物一氧化氮合酶抑制剂 N(G)-硝基-L-精氨酸甲酯盐酸盐（L-NAME）或 NO 特异性清除剂 2-(4-羧基苯基)-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物钾盐（cPTIO）时，叶绿素含量的恢复被阻断。此外，光的诱导效应与 SNP、血红素和 CO 对 Pfr 积累和 PHYA 转录物的诱导效应不同。然而，SNP、血红素和 CO 都能加速 NO 的释放，这表明 HO/CO 在黑暗-光照转换过程中对小麦幼苗去黄化可能与 NO 存在交叉对话。
