Intronic T-DNA Insertion Renders Arabidopsis opr3 a Conditional Jasmonic Acid-Producing Mutant
Intronic T-DNA Insertion Renders Arabidopsis opr3 a Conditional Jasmonic Acid-Producing Mutant
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DOI：
10.1104/pp.111.174169
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发表时间：
2011-06-01
期刊：
影响因子：
7.4
通讯作者：
Braam, Janet
中科院分区：
文献类型：
--
作者：
Chehab, E. Wassim;Kim, Se;Braam, Janet
茉莉酸及其衍生代谢物（JAs）协调植物对昆虫和真菌的防御。12-氧代-植物二烯酸（OPDA），一种JA前体，也参与植物防御。我们试图通过比较三种拟南芥（Arabidopsis thaliana）基因型的防御敏感性特征来定义JAs和OPDA功能：aos，缺乏JAs和OPDA; opda还原酶3（opr 3），缺乏JA生产但可以积累OPDA;和过表达OPR 3的转基因。opr 3与aos一样，对甘蓝夜蛾（Trichoplusianni）敏感，但相对于aos，opr 3对坏死营养型真菌具有增强的抗性。气相色谱-质谱法显示，opr 3产生OPDA，但没有检测到的JA受伤和环虫感染后，出乎意料的是，大量水平的JA积累在opr 3真菌感染。全长OPR 3转录物在真菌感染的opr 3中积累，可能是通过剪接含有内含子的T-DNA。真菌抗性与JA水平相关，而与OPDA水平相关;因此，opr 3对某些害虫的抗性可能是由于JA积累所致，应重新评估归因于OPDA的信号传导活性，因为opr 3可以产生JA。总之，这些数据（1）加强了JAs在植物防御昆虫和坏死性真菌中的主要作用，（2）主张重新评估归因于OPDA的信号活性，（3）提供证据表明插入内含子的突变体可以保留基因功能。
Jasmonic acid and its derived metabolites (JAs) orchestrate plant defense against insects and fungi. 12-Oxo-phytodienoic acid (OPDA), a JA precursor, has also been implicated in plant defense. We sought to define JAs and OPDA functions through comparative defense susceptibility characteristics of three Arabidopsis (Arabidopsis thaliana) genotypes: aos, lacking JAs and OPDA; opda reductase3 (opr3), deficient in JA production but can accumulate OPDA; and transgenics that overexpress OPR3. opr3, like aos, is susceptible to cabbage loopers (Trichoplusia ni) but, relative to aos, opr3 has enhanced resistance to a necrotrophic fungus. Gas chromatography-mass spectrometry reveals that opr3 produces OPDA but no detectable JAs following wounding and looper infestation; unexpectedly, substantial levels of JAs accumulate in opr3 upon fungal infection. Full-length OPR3 transcripts accumulate in fungal-infected opr3, potentially through splicing of the T-DNA containing intron. Fungal resistance correlates with levels of JAs not OPDA; therefore, opr3 resistance to some pests is likely due to JA accumulation, and signaling activities ascribed to OPDA should be reassessed because opr3 can produce JAs. Together these data (1) reinforce the primary role JAs play in plant defense against insects and necrotrophic fungi, (2) argue for a reassessment of signaling activities ascribed to OPDA, and (3) provide evidence that mutants with intron insertions can retain gene function.