Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide. Management through the deployment of host resistance genes would be facilitated by understanding the dynamics of the pathogen's population in the field. Here, to investigate the mechanism underlying the breakdown of disease resistance, we conducted a six-year field experiment to monitor the evolution of M. oryzae populations in Qujiang from Guangdong. The new variety of XYZ carrying R genes Pi50 and Pib was developed using the susceptible elite variety, MBYZ, as the recurrent line. Field trails of disease resistance assessment revealed that the disease indices of XYZ in 2012, 2013, 2016, and 2017 were 0.19, 0.39, 0.70, and 0.90, respectively, indicating that XYZ displayed a very rapid increase of disease severity in the field. To investigate the mechanism underlying the quick erosion of resistance of XYZ, we collected isolates from both XYZ and MBYZ for pathogenicity test against 6 different isogenic lines. The isolates collected from XYZ showed a similar virulence spectrum across 4 different years whereas those from MBYZ showed increasing virulence to the Pi50 and Pib isogenic lines from 2012 to 2017. Molecular analysis of AvrPib in the isolates from MBYZ identified four different AvrPib haplotypes, i.e., AvrPib-AP1-1, AvrPib-AP1-2, avrPib-AP2, and avrPib-AP3, verified by sequencing. AvrPib-AP1-1 and AvrPib-AP1-2 are avirulent to Pib whereas avrPib-AP2 and avrPib-AP3 are virulent. Insertions of a Pot3 and an Mg-SINE were identified in avrPib-AP2 and avrPib-AP3, respectively. Two major lineages based on rep-PCR analysis were further deduced in the field population, implying that the field population is composed of genetically related isolates. Our data suggest that clonal propagation and quick dominancy of virulent isolates against the previously resistant variety could be the major genetic events contributing to the loss of varietal resistance against rice blast in the field.Penicillium crustosum Thom. is a fungus commonly found on cheese and nuts, but is also a postharvest pathogen that causes blue mold disease of pome and stone fruits including plum and nectarine (Louw and Korsten 2016; Restuccia et al. 2006). The fungus produces mycotoxins (penitrem A, roquefortine C, terrestric acid, and cyclopenol) which are of concern for human health (Frisvad and Samson 2004). In Serbia, P. crustosum has been previously described on apple fruit (Vico et al. 2014). On nectarine fruit (Prunus persica var. nucipersica), after 6 weeks of cold storage, symptoms of blue mold developed in a fruit market in Belgrade, Serbia. The fruit was collected and isolations performed in November 2017. Decayed areas on infected fruit were soft, light to medium brown with blue-green sporulation on the fruit surface. Two isolates were obtained (N2AS and N2BS) and cultured on Czapek yeast autolysate agar (CYA), malt extract agar (MEA), yeast extract sucrose agar (YES) and potato dextrose agar (PDA) at 25°C for 72014. Plant Dis. 981430. https://www.selleckchem.com/products/mk-8245.html Acknowledgment This research was supported by the project III46008, No. 451-03-68/2020-14/200116, financed by the Ministry of Education, Science and Technological Development, Republic of Serbia.Chinese cabbage (Brassica rapa L.) is one of the most important vegetables in Korea due to its role as the main ingredient for the making of Kimchi. In June 2014, disease symptoms of leaves wilt, dry, and drop off on Chinese cabbage were observed in a Chinese cabbage farm located at Taebeak (37°26'50.7"N 128°95'50.0"E), Gangwon province, Korea. This disease was observed on approximately 35% of the plants in the field, causing an almost 10% decrease in total production. At the early stage of infection, the color at the edge of the plant foliage changed from green to yellow. As the disease progressed, infected leaves wilted, dried off, and detached from the plant. Soft rot that occurred at the base of the leaf stem and root tissues caused the infected leaves to dry and fell off the plant. To identify the causal agent, a small piece of infected leaf tissues was sterilized with 1% sodium hypochlorite solution for 1 min and rinsed with sterile water before it was transferred onto potato dextrose agar (PDA) media. To our knowledge, this is the first report that V. dahliae causes Verticillium wilt disease on Chinese cabbage in Korea.Improving resistance to barley leaf rust (caused by Puccinia hordei) is an important breeding objective in most barley growing regions worldwide. The development and subsequent utilization of high-throughput PCR-based codominant molecular markers remains an effective approach to select genotypes with multiple effective resistance genes, permitting efficient gene deployment and stewardship. The genes Rph20 and Rph24 confer widely effective adult plant resistance (APR) to leaf rust, are common in European and Australian barley germplasm (often in combination), and act interactively to confer high levels of resistance. Here we report on the development and validation of codominant insertion-deletion (indel) based PCR markers that are highly predictive for the resistance alleles Rph20.ai and Rph24.an (both referred to as Rph20 and Rph24).Helianthus tuberosus L. (Jerusalem artichoke) is an herbaceous perennial plant in the Asteraceae that is native to North America but introduced to China in the 17th century. The tubers of H. tuberosus are used as a vegetable, for the pharmaceutical production of inulin and as a source of ethanol biofuel, several B vitamins and minerals。From June to September 2009, severe powdery mildew infection was observed on H. tuberosus in a vegetable garden at Shangqiu Normal University, Shangqiu, China. Approximately 60% of leaves on individual plants were symptomatic, and almost 70% of the plants were infected. Initially, discrete powdery mildew colonies appeared on the upper surface of the leaves and on stems of the plants. Later, mycelial growth was amphigenous, thick, forming irregular white patches, covering the whole leaf surface. Eventually, leaves turned yellow, withered, and abscissed. Microscopic observations showed that conidia on infected leaves were ellipsoid-ovoid to barrel-shaped, with distinct fibrosin bodies visible in their cytoplasm, measuring 28 to 38 × 15 to 22 μm (n = 40).