Gai Ying-Ping, Han Xue-Juan, Li Yi-Qun, Yuan Chuan-Zhong, Mo Yao-Yao, Guo Fang-Yue, Liu Qing-Xin, Ji Xian-Ling
State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, Shandong, 271018, China.
Plant Cell Environ. 2014 Jun;37(6):1474-90. doi: 10.1111/pce.12255. Epub 2014 Jan 9.
To analyse the molecular mechanisms of phytoplasma pathogenicity, the comprehensive metabolomic changes of mulberry leaf and phloem sap in response to phytoplasma infection were examined using gas chromatography-mass spectrometry. The metabolic profiles obtained revealed that the metabolite compositions of leaf and phloem sap were different, and phytoplasma infection has a greater impact on the metabolome of phloem sap than of leaf. Phytoplasma infection brought about the content changes in various metabolites, such as carbohydrates, amino acids, organic acids, etc. Meanwhile, the results of biochemical analysis showed that the degradation of starch was repressed, and the starch content was increased in the infected leaves. In addition, we found that phytoplasma infection changed the levels of abscisic acid and cytokinin and break phytohormone balance. Interestingly, our data showed that the contents of H2O2 and superoxide were increased in the infected leaves, but not in the phloem saps. Based on the results, the expression levels of the genes involved in the metabolism of some changed metabolites were examined, and the potential molecular mechanisms of these changes were discussed. It can be concluded that both the leaf and phloem saps have a complicated metabolic response to phytoplasma infection, but their response mechanisms were different.
为分析植原体致病性的分子机制，利用气相色谱-质谱联用技术检测了桑树叶片和韧皮部汁液对植原体感染的综合代谢组变化。所得代谢谱显示，叶片和韧皮部汁液的代谢物组成不同，且植原体感染对韧皮部汁液代谢组的影响大于对叶片的影响。植原体感染导致多种代谢物含量发生变化，如碳水化合物、氨基酸、有机酸等。同时，生化分析结果表明，感染叶片中淀粉降解受到抑制，淀粉含量增加。此外，我们发现植原体感染改变了脱落酸和细胞分裂素水平，打破了植物激素平衡。有趣的是，我们的数据显示，感染叶片中过氧化氢和超氧化物含量增加，但韧皮部汁液中未增加。基于这些结果，检测了一些变化代谢物代谢相关基因的表达水平，并探讨了这些变化的潜在分子机制。可以得出结论，叶片和韧皮部汁液对植原体感染均有复杂的代谢反应，但它们的反应机制不同。
