作物学报2016，Vol.42Issue(5)：734-742,9.DOI:10.3724/SP.J.1006.2016.00734
多胺氧化酶(PAO)调控光诱导玉米中胚轴伸长的生理机制
Physiological Mechanism Regulating Light-induced Mesocotyl Elongation by Polyamine Oxidase (PAO) in Maize
摘要
Abstract
In this study, maize inbred line PH4CV was cultured under in MS medium under both dark and light conditions to in-vestigate the relationship of length of mesocotyl with activity of polyamine oxidase (PAO), activity of peroxidase (POD), contents of H2O2 and lignin. In addition, after treated with 5 mmol L-12-hydroxyethyl hydrazine (2-HEH) and 5 mmol L-1 N, N'-Dimethylthiourea (DMTU), the origin and accumulation site of H2O2 in mesocotyl elongation were assessed by using histo-chemical staining method and the effect of light on expression of ZmPAO gene was evaluated. The results indicated that the elon- gation of mesocotyl was significantly inhibited while the contents of H2O2 and lignin and the activities of POD and PAO were enhanced by light. Correlation analysis showed that the length of mesocotyl was negatively correlated with the PAO activity, H2O2 content, POD activity, and lignin content, and the PAO activity was positively correlated with the H2O2 content, the POD activity, and the lignin content. The assay with 2-HEH and DMTU, the microgram of epidermal cells, and histochemical localization of H2O2 revealed that H2O2 participated in mesocotyl elongation, in which PAO catalyzed polyamines (PAs) degradation to produce H2O2 resulting in the inhibition of mesocotyl elongation. Results of qRT-PCR revealed that the expression level of ZmPAO was relatively stable in dark and rose rapidly of 0.5 hour after exposing to light, with a maximum value after three hours of light treatment, then declined gradually, and finally showed a steady level after ten hours. This study suggests that the activity of PAO can be promoted by light treatment, and initiate the PAs-mediated induction of H2O2, resulting in the oxidation of lignin mono-mers on cell wall by POD. The produced free radicals are then transformed into lignin in a polyforming process which marked the cell wall hardened and cell elongation inhibited. This study may provide a theoretical basis for understanding the physiological mechanism underlying the PAO-mediated mesocotyl elongation and gain insights into the response of maize mesocotyl to the light stress.关键词
玉米/光照/中胚轴伸长/多胺氧化酶/表达分析Key words
Maize/Light/Mesocotyl elongation/Polyamine oxidase/Expression analysis引用本文复制引用
张同祯,李永生,李玥,姚海梅,赵娟,王婵,赵阳,王汉宁,方永丰..多胺氧化酶(PAO)调控光诱导玉米中胚轴伸长的生理机制[J].作物学报,2016,42(5):734-742,9.基金项目
本研究由国家重点基础研究发展计划(973计划)前期研究专项(2012CB722902),国家自然科学基金项目(31371708, 31201279)和甘肃省干旱生境作物学重点实验室开放基金项目(GSCS-2012-10)资助. This study was supported by National Basic Research Program of China (973 Program, 2012CB722902), the National Natural Science Foun-dation of China (31371708, 31201279), and Research Program Sponsored by Gansu Provincial Key Laboratory of Aridland Crop Science (GSCS201210). （973计划）
