链霉菌769与百日草黑斑病病菌诱导百日草几丁质酶基因的表达差异

Gene expression difference between chitinase gene induced by Streptomyces gongzhulingensis 769 and Alternaria zinniae in Zinnia elegans

以百日草为试验材料,利用同源基因克隆法克隆到百日草几丁质酶基因片段和actin基因片段,分别用链霉菌769发酵液和百日草黑斑病病菌悬浮液处理百日草植株,通过半定量RT-PCR检测了不同处理的几丁质酶基因表达量的差异。结果表明,链霉菌769发酵液和百日草黑斑病病菌悬浮液均能诱导百日草几丁质酶基因的表达,其最大表达量分别在接种后24 h和6 h。百日草黑斑病病菌优先诱导植株体内几丁质酶的表达,而链霉菌769的诱导滞后。当用病原菌处理36 h后喷施链霉菌769发酵液,链霉菌769对几丁质酶基因的诱导表达高峰出现在喷施后的36 h,比单独喷施的诱导表达推迟了12 h,暗示了生防菌链霉菌769可以诱导植物的系统诱导抗性,且和百日草黑斑病病菌引发了不同的信号转导通路,以减轻由病原菌侵染引发的植物病害。

Difference of chitinase gene expression in Zinnia elegans between the treated fermentation production by Strep- tomyces gongzhulingensis 769 and spore suspension of Alternaria zinniae was determined by semi-quantitative RT-PCR. Actin gene and chitinase gene of Z. elegans were cloned by homologous gene sequence method. The results showed that chitinase gene could be induced by both S. gongzhulingensis 769 fermentation production and spore suspension of A. zin- niae, and maximum expression level emerged after inoculated 24 hours and 6 hours respectively, which indicated that chitinase could be induced earlier by A. zinniae than that by S. gongzhulingensis 769. Chitinase gene expression by induc- ing in the plant treated by spore suspension of A. zinniae for 36 h reached peak in 36 h after inoculated by S. gongzhulin- gens/s 769 fermentation production, which was 12 h later than that treated only by strain 769 fermentation. The results in- dicated that the pathogen and the biocontrol bacteria activated different signaling pathway to induce plant system resis- tance to reduce plant diseases caused by pathogens.