Zhang Zhengguang

Mammalian pro-apoptotic bax gene enhances tobacco resistance to pathogens

Emerging evidence suggests that plants and animals may share certain biochemical commonalities in apoptosis, or programmed cell death (PCD) pathways, though plants lack key animal apoptosis related genes. In plants, PCD has many important functions including a role in immunity and resistance to pathogen infection. In this study, a rice phenylalanine ammonia-lyase promoter is used to regulate the expression of the mouse pro-apoptotic bax gene in transgenic tobacco plants. Ectopic expression of the bax negatively affects the growth of transgenic plants. Nonetheless, results show that the bax transgene is induced upon infection by plant pathogens and accumulation of Bax is observed by Western blot analysis. By estimating and measuring the extent of cell death, release of active oxygen species, and accumulation defense-associated gene transcripts, it is shown that bax transgenic plants mount a more robust cell death response compared to control plants. The bax transgenic tobacco plants are also more resistant to infection by Phytophthoraparasitica and Ralstoniasolanacearum, but have no obvious resistance to tobacco mosaic virus. These results substantiate past studies and illustrate the powerful effects mammalian bax genes may have on plant development and disease resistance.Emerging evidence suggests that plants and animals may share certain biochemical commonalities in apoptosis, or programmed cell death (PCD) pathways, though plants lack key animal apoptosis related genes. In plants, PCD has many important functions including a role in immunity and resistance to pathogen infection. In this study, a rice phenylalanine ammonia-lyase promoter is used to regulate the expression of the mouse pro-apoptotic bax gene in transgenic tobacco plants. Ectopic expression of the bax negatively affects the growth of transgenic plants. Nonetheless, results show that the bax transgene is induced upon infection by plant pathogens and accumulation of Bax is observed by Western blot analysis. By estimating and measuring the extent of cell death, release of active oxygen species, and accumulation defense-associated gene transcripts, it is shown that bax transgenic plants mount a more robust cell death response compared to control plants. The bax transgenic tobacco plants are also more resistant to infection by Phytophthora parasitica and Ralstonia solanacearum, but have no obvious resistance to tobacco mosaic virus. These results substantiate past studies and illustrate the powerful effects mammalian bax genes may have on plant development and disease resistance.

No significant differences in rhizosphere bacterial communities between Bt maize cultivar IE09S034 and the near-isogenic non-Bt cultivar Zong31

Liang J.G., Luan Y., Jiao Y., Xin L.T., Song X.Y., Zheng X.B., Zhang Z.G. (2018): No significant differences in rhizosphere bacterial communities between Bt maize cultivar IE09S034 and the near-isogenic non-Bt cultivar Zong31. Plant Soil Environ., 64: 427–434. The release of genetically modified (GM) crops has potential to alter the bacterial population within rhizosphere. Here, the potential effect of GM maize cv. IE09S034 containing the Cry1Ie toxin gene from Bacillus thuringiensis (Bt) was investigated under the field conditions. The community composition and the relative abundance of the bacteria in rhizosphere soil were estimated by analysing 16S rRNA PCR amplicons. Our results indicated that Bt maize IE09S034 has no significant effects on the rhizosphere bacterial community. Instead, it was found that factors such as plant growth stage and year have a stronger effect on the bacterial population dynamics. Our findings therefore provide reliable evidence supporting the potential commercial cultivation of the cv. IE09S034.