Unique morphological changes in plant pathogenic phytoplasma-infected petunia flowers are related to transcriptional regulation of floral homeotic genes in an organ-specific manner
Unique morphological changes in plant pathogenic phytoplasma-infected petunia flowers are related to transcriptional regulation of floral homeotic genes in an organ-specific manner
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DOI：
10.1111/j.1365-313x.2011.04650.x
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发表时间：
2011-09-01
期刊：
影响因子：
7.2
通讯作者：
Namba, Shigetou
中科院分区：
文献类型：
--
作者：
Himeno, Misako;Neriya, Yutaro;Namba, Shigetou
异常的花通常是由某些植物病原体的感染引起的，例如。 g。植原体，但这些畸形背后的分子机制仍然知之甚少。在这里，我们发现 OY-W 植原体（Candidatus phytoplasma asteris，洋葱黄化植原体菌株，OY-W 系）的感染以器官特异性方式影响矮牵牛植物花同源异型基因的表达。感染 OY-W 植原体后，在萼片、花瓣和雌蕊中观察到花形态变化，包括转变为叶状结构，但在雄蕊中没有观察到。由于花器官之间同源基因的表达水平差异很大，我们检查了被 OY-W 植原体感染的每个花器官中同源基因的表达水平，并与健康植物进行比较。除雄蕊外的花器官中，器官发育所需的几种同源基因（如 PFG、PhGLO1 和 FBP7）的表达水平因植原体感染而显着下调，表明植原体感染引起的独特形态变化可能是由于一些关键同源基因表达的显着降低所致。此外，已知参与花分生组织身份的TER、ALF和DOT基因的表达水平在植原体感染的矮牵牛分生组织中显着下调，这意味着植原体会影响花分生组织身份的上游信号通路。我们的结果表明，植原体感染可能对花发育产生复杂的影响，导致独特的表型，与某些同源基因敲除或过度表达产生的突变花表型明显不同。
Abnormal flowers are often induced by infection of certain plant pathogens, e. g. phytoplasma, but the molecular mechanisms underlying these malformations have remained poorly understood. Here, we show that infection with OY-W phytoplasma (Candidatus Phytoplasma asteris, onion yellows phytoplasma strain, line OY-W) affects the expression of the floral homeotic genes of petunia plants in an organ-specific manner. Upon infection with OY-W phytoplasma, floral morphological changes, including conversion to leaf-like structures, were observed in sepals, petals and pistils, but not in stamens. As the expression levels of homeotic genes differ greatly between floral organs, we examined the expression levels of homeotic genes in each floral organ infected by OY-W phytoplasma, compared with healthy plants. The expression levels of several homeotic genes required for organ development, such as PFG, PhGLO1 and FBP7, were significantly downregulated by the phytoplasma infection in floral organs, except the stamens, suggesting that the unique morphological changes caused by the phytoplasma infection might result from the significant decrease in expression of some crucial homeotic genes. Moreover, the expression levels of TER, ALF and DOT genes, which are known to participate in floral meristem identity, were significantly downregulated in the phytoplasma-infected petunia meristems, implying that phytoplasma would affect an upstream signaling pathway of floral meristem identity. Our results suggest that phytoplasma infection may have complex effects on floral development, resulting in the unique phenotypes that were clearly distinct from the mutant flower phenotypes produced by the knock-out or the overexpression of certain homeotic genes.