Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola is one of the most economically important disease affecting common bean production in Ethiopia. Until now, no information has been generated regarding the pathotype and pathogenic variability and its distribution in Ethiopia. A study was undertaken to characterize the pathotype and virulence variability among 39 P. griseola isolates, ALS pathogen, occurring in Ethiopia. A total of 21 pathotypes (63:63, 63:59, 63:23, 61:51, 56:36, 55:39, 49:7, 48:60, 42:59, 41:10, 34:53, 23:61, 19:33, 17:45, 8:18, 8:0, 4:16, 1:24, 1:10, 16:18. and 4:37) were determined using 12 sets of ALS common bean differentials cultivars. These results revealed the presence of high and diverse pathogenic variability of the pathogen. Among the determined pathotypes 63:59 and 19:33 were the most frequently appeared. And the occurrence of three pathotypes (63:63, 63:59 and 63:23) were confirmed as well as the previous reports in central America and Argentina. This will be the first comprehensive report of P. griseola pathotypes existing in the common bean growing areas of Ethiopia. Except pathotype 8:0 that were compatible with Andean common bean groups, most of the isolates were pathogenic to both Andean and Mesoamerican common bean gene pools. Based on that, the isolates were classified as Mesoamerican origin pathotypes. This specific study provided major information about the pathogenic diversity and determined the pathotype of P. griseola from common bean in Ethiopia.
Bacterial Brown Stripe of Rice (BBSR), caused by Pseudomonas syringae pv. panici (Elliott) stepp and/or Acidovorax avenae subsp. avenae, also called heart rot disease of rice, was firstly reported in 1989 in China. The disease was minority rice disease and occasionally occurred at small scale in rice production area of Yangtze River basin and southern China in the past three decades. It also occurred in northern cold region of rice growing and aggravated in recent years. The rate of the diseased plants was 20% to 25% in common paddy fields infected by BBSR, whereas the disease happened seriously, the mortality rate of seedling could reach above 60%. However, the BBSR was seriously outbreak in 2018 in China, the area including Sichuan, Hunan, Hubei, Anhui and Chongqing provinces (municipality) in upper reaches of Yangtze River, Liaoning and Jilin provinces in northeast, there are more than 100 thousand hectare of rice field were seriously infected (caused large scale of rice plants destroyed) by BBSR, the major varieties are Y Liangyou 957 (hybrid rice) and Yanjing 47 (japonica), shown in Figures 1-4.
This work was supported by the projects: The National Key R&D Program of China (2018YFD0200304, 2016YFD0200801), Innovation project of Chinese Academy of Agricultural Sciences (CAAS) (CAAS-ASTIP -2013-CNRRI, CAAS-XTCX2016012).