Presence of two glycolytic gene clusters in a severe pathogenic line of Candidatus Phytoplasma asteris.
Presence of two glycolytic gene clusters in a severe pathogenic line of Candidatus Phytoplasma asteris.
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DOI：
10.1111/j.1364-3703.2007.00408.x
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发表时间：
2007-07
影响因子：
4.9
通讯作者：
K. Oshima;S. Kakizawa;R. Arashida;Y. Ishii;A. Hoshi;Y. Hayashi;S. Kagiwada;S. Namba
中科院分区：
文献类型：
--
作者：
K. Oshima;S. Kakizawa;R. Arashida;Y. Ishii;A. Hoshi;Y. Hayashi;S. Kagiwada;S. Namba
摘要植原体是植物病原细菌，与多种植物病害有关。我们以前报道过星状假丝酵母Oy株、Oy-M株的全基因组序列，该株能引起轻微症状。植原体基因组缺乏几个重要的代谢基因，这意味着植原体对代谢产物的消耗可能会引起植物的病害症状。在这里，我们发现包括糖酵解基因在内的大约30kb的区域在Oy-W植原体基因组中被随机复制，这会导致严重的症状。几乎重复的基因通过移码和终止密码子突变成为假基因，可能是因为它们的功能冗余。然而，包括两个糖酵解基因在内的5种基因仍然是全长ORF，这表明植原体在其生活方式中保留这些基因是有利的。特别是，6-磷酸果糖激酶是糖酵解的限速酶，这意味着Oy-W和Oy-M之间不同数量的糖酵解基因可能会影响它们各自的糖酵解活性。我们以前报道过，Oy-W的植原体数量高于Oy-M的感染植株。考虑到这一结果，较高的碳源消耗可能会影响植原体的生长速度，也可能直接或间接造成更严重的症状。
SUMMARY Phytoplasmas are plant-pathogenic bacteria that are associated with numerous plant diseases. We have previously reported the complete genomic sequence of Candidatus Phytoplasma asteris, OY strain, OY-M line, which causes mild symptoms. The phytoplasma genome lacks several important metabolic genes, implying that the consumption of metabolites by phytoplasmas in plants may cause disease symptoms. Here we show that the approximately 30-kb region including the glycolytic genes was tandemly duplicated in the genome of OY-W phytoplasma, which causes severe symptoms. Almost duplicated genes became pseudogenes by frameshift and stop-codon mutations, probably because of their functional redundancy. However, five kinds of genes, including two glycolytic genes, remained full-length ORFs, suggesting that it is advantageous for the phytoplasma to retain these genes in its lifestyle. In particular, 6-phosphofructokinase is known as a rate-limiting enzyme of glycolysis, implying that the different number of glycolytic genes between OY-W and OY-M may influence their respective glycolysis activities. We previously reported that the phytoplasma population of OY-W was higher than that of OY-M in their infected plants. Taking this result into account, the higher consumption of the carbon source may affect the growth rate of phytoplasmas and also may directly or indirectly cause more severe symptoms.