Pathogen-induced calmodulin isoforms in basal resistance against bacterial and fungal pathogens in tobacco
Pathogen-induced calmodulin isoforms in basal resistance against bacterial and fungal pathogens in tobacco
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DOI：
10.1093/pcp/pcm011
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发表时间：
2007-03-01
影响因子：
4.9
通讯作者：
Ohashi, Yuko
中科院分区：
文献类型：
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作者：
Takabatake, Reona;Karita, Eri;Ohashi, Yuko
13个烟草钙调素（CaM）基因可分为三种不同的氨基酸同源型。烟草花叶病毒（TMV）介导的超敏反应中，伤口诱导型NtCaM1和2有中度诱导作用，III型NtCaM13有高度诱导作用，II型NtCaM3-NtCaM12反应不明显。利用NtCaM1和ntcam13的反向重复序列分别构建了I型和III型低敲烟草株系，以评估病原体诱导的钙调素（CaMs）对抗病的贡献。在证实了两种转基因系中I型和III型CaM基因表达的特异性降低后，我们分析了对TMV感染的反应，发现与对照系相比，III型CaM敲低系的TMV易感性略有增强。对细菌病原菌茄枯菌、真菌病原菌茄根丝核菌和蛇皮霉的抗性在ⅲ型植物中显著降低，而在ⅰ型植物中则没有。茉莉酸（JA）和/或乙烯诱导的基本PR基因的表达在这些品系中没有受到影响，这表明III型CaM亚型可能以独立于JA和乙烯信号的方式参与对坏死性病原体的基础防御。
Thirteen tobacco calmodulin (CaM genes fall into three distinct amino acid homology types. Wound-inducible type I isoforms NtCaM1 and 2 were moderately induced by tobacco mosaic virus (TMV)-mediated hypersensitive reaction, and the type III isoform NtCaM13 was highly induced, while the type II isoforms NtCaM3-NtCaM12 showed little response. Type I and III knockdown tobacco lines were generated using inverted repeat sequences from NtCaM1 and 13, respectively, to evaluate the contribution of pathogen-induced calmodulins (CaMs) to disease resistance. After specific reduction of type I and III CaM gene expression was confirmed in both transgenic lines, we analyzed the response to TMV infection, and found that TMV susceptibility was slightly enhanced in type III CaM knockdown lines compared with the control line. Resistance to a compatible strain of the bacterial pathogen Ralstonia solanacearum, and fungal pathogens Rhizoctonia solani and Pythium aphanidermatum was significantly lower in type III but not in type I CaM knockdown plants. Expression of jasmonic acid (JA)- and/or ethyleneinducible basic PR genes was not affected in these lines, suggesting that type III CaM isoforms are probably involved in basal defense against necrotrophic pathogens in a manner that is independent of JA and ethylene signaling.