Faba bean (Vicia faba L.) is one of the most important legume crops in Egypt. However, production of faba bean is affected by several diseases including fungal diseases. Fusarium wilt incited by Fusarium oxysporum Schlecht. was shown to be the most common wilt disease of faba bean in Assiut Governorate. Evaluation of 16 faba bean genotypes for the resistance to Fusarium wilt was carried out under greenhouse conditions. Three molecular marker systems (inter-simple sequence repeat [ISSR], sequence related amplified polymorphism [SRAP], and simple sequence repeat [SSR]) and a biochemical marker (protein profiles) were used to study the genetic diversity and detect molecular and biochemical markers associated with Fusarium wilt resistance in the tested genotypes. The results showed that certain genotypes of faba bean were resistant to Fusarium wilt, while most of the genotypes were highly susceptible. The percentage of disease severity ranged from 32.83% in Assiut-215 to 64.17% in Misr-3. The genotypes Assiut-215, Roomy-3, Marut-2, and Giza-2 were the most resistant, and the genotypes Misr-3, Misr-1, Assiut-143, Giza-40, and Roomy-80 performed as highly susceptible. The genotypes Assiut-215 and Roomy-3 were considered as promising sources of the resistance to Fusarium wilt. SRAP markers showed higher polymorphism (82.53%) compared with SSR (76.85%), ISSR markers (62.24%), and protein profile (31.82%). Specific molecular and biochemical markers associated with Fusarium wilt resistance were identified. The dendrogram based on combined data of molecular and biochemical markers grouped the 16 faba bean genotypes into three clusters. Cluster I included resistant genotypes, cluster II comprised all moderate genotypes and cluster III contained highly susceptible genotypes.

No abstract

No abstract

Background The bacterial speck disease of tomato caused by a bacterial pathogen Pseudomonas syringae pv. tomato is a most important disease causing severe crop losses. Methods and results Present study was conducted to investigate and characterize the population diversity of P. syringae pv. tomato pathogen isolated from infected tomato plants from various regions of Egypt. Significant variation among the isolates was observed which demonstrated considerable virulence. All isolates were pathogenic and the CFU population recovered from inoculate tomato leaves by isolate Pst-2 was higher than other isolates. Genetic disparity among the isolates was investigated by PCR analysis by amplifying hrpZ gene using random amplified polymorphic DNA (RAPD), sequence-related amplified polymorphism (SRAP), and inter-simple sequence repeats (ISSR) markers. The amplified products for ITS1 were found to have 810 bp length whereas 536 bp length was observed for hrpZ gene using primer pairs (1406-f/23S-r) and (MM5-F, MM5-R) respectively. The restriction analysis of amplified regions “ITS” and hrpZ by using 5 and 4 endonucleases respectively demonstrated slight variation among the bacterial isolates. The results of RAPD, ISSR and SRAP showed higher polymorphism (60.52%) within the isolates which may assist for successful characterization by unique and specific markers based on geographical distribution, origin and virulence intensity. Conclusion The results of present study suggested that the use of molecular approach may provide successful and valuable information to differentiate and classify P. syringae pv. tomato strains in future for the detection and confirmation of pathogenicity.

No abstract