Heterologous expression of the Hsp24 from Trichoderma asperellum improves antifungal ability of Populus transformant Pdpap-Hsp24 s to Cytospora chrysosperma and Alternaria alternate

The tolerance of plants to biotic and abiotic stresses could be improved by transforming with fungal resistance-related genes. In this study, the cDNA sequence (GenBank Acc. No. KP337939) of the resistance-related gene Hsp24 encoding the 24 kD heat shock protein was obtained from the biocontrol fungus Trichoderma asperellum ACCC30536. The promoter region of Hsp24 contained many cis-regulators related to stresses response, such as "GCN4" and "GCR1" etc. Hsp24 transcription in T. asperellum was up-regulated under six different environmental stresses, compared with the control. Furthermore, following heterologous transformation into Populus davidiana × P. alba var. Pyramidalis (Pdpap), Hsp24 was successfully transcribed in transformant Pdpap-Hsp24s. Pathogen-related genes (PRs) in four Pdpap-Hsp24s were up-regulated compared with those in the control Pdpap (Pdpap-Con). After co-culture of Pdpap-Hsp24s with the weak parasite Cytospora chrysosperma, the transcription of genes related to hormone signal pathway (JA and SA) were up-regulated in Pdpap-Hsp24s, and ethidium bromide (EtBr) and Nitro-blue tetrazolium (NBT) staining assays indicated that the cell membrane permeability and the active oxygen content of Pdpap-Hsp24s leaves were lower than that of the control Pdpap-Con. And when the Pdpap-Hsp24s were under the Alternaria alternate stress, the activities of superoxide dismutase (SOD) and peroxidase (POD) got higher in Pdpap-Hsp24s than that in Pdpap-Con, and the disease spots in Pdpap-Con leaves were obviously larger than those in Pdpap-Hsp24s leaves. In summary, Hsp24 of T. asperellum ACCC30536 is an important defense response gene, and its heterologous expression improved the resistance of transformant Pdpap-Hsp24s to C. chrysosperma and A. alternate.

Solar-thermochromism of a hybrid film of VO2 nanoparticles and CoII–Br–TMP complexes

This work reports a VO₂/Co^II–Br–TMP hybrid film with excellent optical performance and an evident temperature-dependent colour change.

Analysis of specific sequences in mutant rice generated by introduction of exogenous corn DNA

Rice variation induced by the introduction of exogenous DNA has become an important method of improving rice varieties and creating new germplasms. In this study, we transferred maize genomic DNA fragments to the receptor of Nipponbare rice using a modified "pollen-tube pathway" method. Material from mutant rice B1 and B2 were acquired and 14 specific bands were obtained from the material using amplified fragment length polymorphism analysis. From the 14 specific sequences obtained, there were 3791 bp, including 144 base mutations with a base mutation rate of 3.80%. Specific bands resulted from base mutation of selective bases or restriction endonuclease recognition sequences, or insertion or deletion of DNA fragments. The frequency of single-base mutations was significantly higher than that of double-base mutations, three-sequential base mutations, and multiple-sequential base mutations. The site frequency of base substitution (87.04%) was significantly higher than that of base insertion (3.70%) or deletion (9.26%). In all cases of base substitution, the frequency of transition (76.47%) was significantly higher than transversion (23.53%). The above results indicate that transferring foreign-species DNA into rice cells can induce base mutations in the receptor, with base substitutions occurring at the highest frequency, and the dominant type of base substitutions being transition. Preliminary analysis reveals that the molecular mechanism of transferring exogenous DNA into rice causes mutations, which provides theoretical data on biological mutagenesis for further research.

Morphology and photosynthetic enzyme activity of maize phosphoenolpyruvate carboxylase transgenic rice

The morphology and photosynthetic enzyme activity were studied in maize phosphoenolpyruvate carboxylase transgenic rice and non-transgenic rice. The results showed that compared with non-transgenic rice, phosphoenolpyruvate carboxylase transgenic rice was taller and had a stronger stalk, wider leaves, and more exuberant root system, with increased photosynthetic enzyme activity and improved yield components. Therefore, given the superiority of this plant type and heterosis, this is a novel breeding strategy for rice for the introduction of C4 photosynthesis genes into high-yielding rice.

Ion beam transformation with corn DNA alters proteinase expression in rice seedling roots

Corn DNA was introduced into dry seeds of rice (cv. 'YuJing-6') by ion beam irradiation. Proteinase activities in rice seedling roots were subsequently analyzed by renaturation electrophoresis at pH 4.5, 7.0, and 8.5. Proteinase activity was more pronounced on gels at higher pH. Irradiation of rice seedling roots caused the loss of some proteinase bands at all pH conditions although a novel 50-kDa band was found at both pH 7.0 and 8.5. No new proteinase activity was detected at pH 4.5. However, novel bands and bands showing stronger activity were observed at pH 7.0 and 8.5. The data indicate that the expression of proteinases in rice seedling roots was altered following low energy ion beam mediated transformation with corn DNA.