文章目录

1. Introduction

2. Materials and methods

2.1. Plant materials and growth conditions

2.2. Rice transformation and transgenic plant analysis

2.3. RNA extraction and q RT-PCR analysis of gene expression

2.4.3,3-Diaminobenzidine (DAB) staining

2.5. Metabolite profiling

2.6. GWAS and linkage map analyses

2.7. Phylogenetic analysis

2.8. In vitro enzyme assays

2.9. Enzyme kinetics

2.1 0. Pathogen infection

2.1 1. Electrophoretic mobility shift assay (EMSA)

2.1 2. One-hybrid assays in yeast

2.1 3. Transcriptional repression assay in N.benthamiana leaves

2.1 4. Chromatin immunoprecipitation (Ch IP)-q PCR analysis

2.1 5. Statistics

3. Results

3.1. Os ODC,Os PHT3,and Os PHT4 clusters on chromosome 9

3.2. M.oryzae infection induces HP cluster genes

3.3. Os PHT3 and Os PHT4 confer PHT activity-dependent resistance

3.4. Os PHT3 and Os PHT4 overexpression in rice leads to cell death phenotypes

3.5. TF APIP5 binds to the Os PHT4 promoter

3.6. APIP5 represses the Os PHT4 transcript levels

3.7. The HP gene cluster is conserved in monocots

4.Discussion and conclusion

4.1. Conservation of the HP gene cluster in monocots

4.2. Involvement of PAs in disease resistance and cell death

4.3. Regulation of the HP gene expression by the TF APIP5

Conflict of interest

文章摘要:酚胺代谢物是一类丰富多样的次级代谢物,主要包括羟基肉桂酰腐胺、羟基肉桂酰胍丁胺和羟基肉桂酰色胺,在生物胁迫中扮演着至关重要的角色.然而,其生物合成和调控机制尚不清楚.本研究利用基于代谢物的全基因关联分析（m GWAS）鉴定了一个水稻（Oryza sativa）脂肪族酚胺代谢基因簇-羟基肉桂酰腐胺（HP）基因簇,该基因簇由1个鸟氨酸脱羧酶（Os ODC）和2个串联的腐胺羟基肉桂酰转移酶（Os PHT3和Os PHT4）组成.超量表达Os PHT3和Os PHT4促进了HP的显著积累,诱发了强烈的植物细胞死亡,同时显著提高了水稻对稻瘟菌的抗病性,且它们的表型依赖于其酰基转移酶活性. Os ODC过表达植物也增强了水稻对稻瘟菌的抗病性.进一步研究发现,水稻免疫及细胞死亡负调控转录因子APIP5直接结合Os PHT4的启动子并抑制其表达,进而影响HP的积累.比较基因组学分析表明, HP生物合成基因簇在单子叶植物中具有保守性,暗示HP基因簇在单子叶植物中可能有相似的生物学功能.本研究揭示了单子叶植物特异的脂肪族酚胺代谢基因簇调控水稻免疫及细胞死亡的新机制,为植物细胞死亡及免疫在代谢水平上的研究提供了新的见解.

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