| Wheat is an important food crops in china, however, the high and stable yield seriously affected pests and fungus. In order to obtain quality varieties of wheat, the genetic engineering technology was used and riboflavin was sprayed. Transgenic plants containing antibiotic or herbicide resistance marker genes were used more, but the presence of these marker genes caused bio-safety issues. In addition, the marker genes which are in the risk assessment process take a lot of money, but also the products of these genes in transgenic plants of which the release will take some time. Therefore, the positive selection system which takes more time and money has rapid advantages of development in recent years because of its security. In our experiment, the positive selection system used pmi gene was selected. Riboflavin (vitamin B2) participates in a variety of redox that produces various functional compounds in plant defensive responses. Riboflavin applied to wheat induces pathogen resistance to powdery mildew (Blumeria graminis f.sp.tritici). Here we report that the application of riboflavin to Wheat induces defensive responses toward infection with powdery mildew. The result showed that the accumulation of H2O2in priming defenses is necessary.1. production of transformation vectors in wheatIn this study, NtTTG2and hapG10-42were selected as our laboratory has conducted a detailed study of them. Our research showed that their products can induce or regulate plant growth and defense response signal transduction. NtTTG2is homologous to NtTTG1which is critical for trichomes to precede mesophylls in activation of the HR pathway; the products of NtTTG1play an important regulatory role on growth and development of plant defense also. HapG10-42is a function fragment of harpin protein HapGXooc which is encoded by rice stripe virus gene. HapG10-42can be used in wheat which can prevent disease and promote vegetative growth of wheat but has no direct impact on the Fusarium graminearum, but the occurrence of induced resistance of plants can inhibit plant identification and contact with production of bacteria DON. We choose Yangmai16and Yangmai158immature embryos as the target collection, which were certificated had more advantage in microprojectile bombardment transformation than other varieties of wheat. Immature embryo derived from Yangmai16and Yangmai158were treated under dark envirenment for2weeks and perfect callus were obtained, then mannose selection system were used to obtain transgenic plants and do a preliminary molecular validation. The result showed that mannose phosphate isomerase gene (PMI (ManA)) is a selection marker of high efficiency for wheat transformation.2. Inhibition of powdery mildew development with foliar application of riboflavin in wheatThe effects of fungicidal activity on leaves applied with RM were detected through restriction of progress of colonies and disease severity compared with control plants. Riboflavin with the concentrations of5mg/l,10mg/l,15mg/l,25mg/l were used respectively, the result showed that foliar application of riboflavin was helpful for wheat to restricting infection of powdery mildew, there is no significantly difference among concentrations of riboflavin. The initial response to foliar application of riboflavin was hydrogen peroxide (H2O2) abruption in the leaves of wheat plants. The content of H2O2also showed higher level in12h after pathogen inoculation compared with control.3d after pathogen inoculation, colonies were abruptly increased in control plants. However, the plants with foliar application of riboflavin showed absolutely defensive symptom.9d after pathogen inoculation, colonies in plants with foliar application of riboflavin were also lower than control. However, when riboflavin was used with CAT (catalase) which can remove H2O2, the defense against powdery mildew induced by riboflavin disappeared; suggesting that the role of H2O2regenerated by riboflavin in priming defenses is necessary and it may be subject to signaling process which was unknown. |
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