Molecular Detection And Resistance Evaluation For Pokkah Boeng Disease Of Sugarcane

Pokkah Boeng disease of sugarcane by Gibberella fujikuroi (Saw.) Wholle causes serious damage to sugarcane industry all over the world. Recently, Pokkah Boeng Disease of sugarcane became a serious threat to the sugarcane production and sugar development in China.Using the seedings from 50 cross combinations and 13 sugarcane varieties as plant material, the resistance of sugarcane to Pokkah Boeng Disease was evaluated according to rating scales under natural field infection. The results indicated that the infection ratings of the 13 sugarcane varieties were as follows: the infection of YZ99-91 is 0. The corresponding infection rate of FN02-3924, YG18, ROC16 was 13.89%, 9.44% and 8.88% respectively. And the results also showed that the seedings from 50 cross combinations should be classified into four types, The infection rate of the 4 combinationgs (YT00-236×ROC22, Hocp93-746×YR03-806, FN91-4710×ROC10 et al.) was 0.83%-1.67% and this group accounted for 8 percent of all the 50 tested cross combinationgs. The infection rate of the other 45 combinationgs (CP84-1198×GT91-116, CP84-1198×YZ94-375 et al.) was 2.50%-10.00% and this group accounted for 90 percent of all the 50 tested cross combinationgs. Besides, the group of FN90-6652 was 15.80%.Research on the isolation, culture and identification of the corresponding pathogen should be helpful to the establishment of the fast identification system and aid to sugarcane Pokkah Boeng disease resistance breeding. In this paper, we cut and inoculation-culture the spot leaves from sugarcane cultivar infected by Gibberella fujikuroi(Saw.)Wholle culture which come from the province of Guangdong, Guangxi and Fujian, and the electron microscope and scanning electron microscopy for morphological observation of the corresponding fungi colonies were also conducted, then the separation of single-spore pathogens, the extraction of its DNA and the molecular identification by ITS-PCR, ATP-PCR and Effd-PCR were conducted. We get the targeted gene fragments of different pathogenic fungi from different sugarcane varieties by the methods of ITS-PCR, ATP-PCR and Effd-PCR. The results of bioinformatics analysis showed that the ITS sequence amplified from the above pathogen was 100% homologous with that of Gibberella moniliformis, 99% homologous with that of Gibberella fujikuroi, which demonstrated that the outcome of ITS-PCR and Effd-PCR identification existed a high degree of compliance with the observation through electron microscope and scanning electron microscope. Then, specific PCR primers were designed according to the ITS sequence and a rapid detection system of sugarcane Pokkah Boeng was established. Comparatively speaking, ATP-PCR is relatively more difficult to distinguish sugarcane Pokkah Boeng and its relative fungus. The results above is meaningful to the breeding of surgarcane variety resistant to Pokkah Boeng.