Molecular Detection And Disease Resistance Identification Of TiMYB2R-1and PgPGIP1in Wheat

The disease take-all, caused by fungus Gaeumannomyces graminis var. tritici, and thedesease common root rot, caused by fungus Bipolaris sorokiniana, are the destructive rootdiseases of wheat worldwide. Breeding resistant cultivars is the most safe and effective wayto protect wheat from take-all and common root rot. As lacking of perfect resistantgermplasms, little progress has made in improving the diseases resistance level in commercialwheat cultivars. Therefore, it is very important to breeding resistant cultivars through geneticengineering.MYB transcription factors play important roles in plant responses to biotic and abioticstresses. Up to now, there is no report about the function of MYB transcription factors inimproving the take-all resistance level in wheat. Polygalacturonase-inhibiting proteins canreduce the infection of some fungal phytopathogens through inhibiting the polygalacturonaseactivity of the pathogens. In the previous work of Institute of Crop Sciences, CAAS, an R2R3MYB transcription factor gene TiMYB2R-1was isolated from a wheat wild-relativeThinopyrum intermedium. The TiMYB2R-1was transformed into wheat cultivar Yangmai12via microprojectile bombardment. After regeneration and resistance selection byGaeumannomyces graminis, resistant plants were grown in plots. The full cDNA sequence ofPgPGIP1gene was synthesized and trnasformed into wheat cultivar Yangmai18viamicroprojectile bombardment. After regeneration and resistance selection byGaeumannomyces graminis and Bialaphos sorokiniana, resistant plants were grown in plots.This study evaluates the inherit stability of TiMYB2R-1and PgPGIP1and whether theexpression of TiMYB2R-1or PgPGIP1enhances the transgenic wheat resistance to take-alland common root rot. TiMYB2R-1and PgPGIP1may be useful for improving these cropresistance.The main results summarized as follows:1. In molecular detection and disease resistant analysis to TiMYB2R-1tansgenic wheat,the hereditary stability of TiMYB2R-1transgenic wheat was confirmed. After PCR detectionto all transgenic wheat plants of T4–T5generation, three of the transgenic wheat linesexpressed TiMYB2R-1. The results indicated the hereditary stability and the homozygous ofTiMYB2R-1gene in the three transgenic wheat lines. 2. In molecular detection and disease resistant analysis to TiMYB2R-1transgenic wheat,the improved resistance to Ggt in over-expression TiMYB2R-1transgenic wheat wasconfirmed. The overexpression of TiMYB2R-1gene in the three transgenic wheat lines wasproved by RT-PCR, Q-RT-PCR and western blotting. And the transcript levels of at least6wheat defense-related genes were significantly elevated. Based disease response assessments,the significantly enhanced-resistance to take-all was observed in the three transgenic wheatlines, and the relative Ggt abundance was significantly lower in the TiMYB2R-1transgenicwheat lines. These results indicate the high transcript level of TiMYB2R-1can enhanceresistance to take-all.3. In molecular detection and disease resistant analysis to PgPGIP1tansgenic wheat, thehereditary stability of PgPGIP1transgenic wheat were confirmed. After PCR detection to alltransgenic wheat plants of T1–T4generation, four of the transgenic wheat lines expressedPgPGIP1. The results indicated the hereditary stability of PgPGIP1gene in the fourtransgenic wheat lines.4. In molecular detection and disease resistant analysis to PgPGIP1transgenic wheat,the improved resistance to Ggt and B. sorokiniana in over-expression PgPGIP1transgenicwheat was confirmed. The transgenic wheat(Yangmail8) plants of T4generation wereinoculated Ggt and B. sorokiniana. The overexpression of PgPGIP1gene in the fourtransgenic wheat lines was manifest by RT-PCR and Q-RT-PCR. The resistance test wasperformed by inoculating Ggt and B. sorokiniana that the PgPGIP1transgenic individuals inT4generation showed high resistance to take-all and common root rot, suggesting that theoverexpression of PgPGIP1enhanced the resistance to take-all and common root rot. So thePgPGIP1gene have a positive role in regulating the plants reaction to diseases.