Late blight disease of potato and tomato, caused by Phytophthora infestans, results in serious losses to Egyptian and global potato and tomato production. To understand the structure and dynamics of the Egyptian population of P. infestans, 205 isolates were collected from potato and tomato plants during three growing seasons in 2010–2012. The characterization was achieved by mating-type assay, metalaxyl sensitivity assay, and virulence pattern. Additionally, genotyping of 85 Egyptian isolates and 15 reference UK isolates was performed using 12 highly informative microsatellite (SSR) markers David E. L. Cooke and five effector (RxLR) genes. Mating-type testing showed that 58% (118 of 205) of the isolates belonged to mating type A1, 35% (71 isolates) to mating type A2, and the rest 8% (16 isolates) were self-fertile. The phenotype of metalaxyl response was represented as 45% resistant, 43% sensitive, and 12% as intermediate. Structure analysis grouped the 85 identified genotypes into two main clonal lineages. The first clonal lineage comprised 21 isolates belonging to A2 mating type and 8 self-fertile isolates. This clonal lineage was identified as Blue_13 or EU_13_A2. The second main clonal lineage comprised 55 isolates and was identified as EU_23_A1. A single isolate with a novel SSR genotype that formed a distinct genetic grouping was also identified. The effector sequencing showed good correspondence with the virulence data and highlighted differences in the presence and absence of loci as well as nucleotide polymorphism that affect gene function. This study indicated a changing population of P. infestans in Egypt and discusses the findings in the context of late blight management.

Early blight incurs huge losses to solanaceous crops at both pre- and post-harvest stages by reducing yields up to 35–78%. Large-spored Alternaria spp. were isolated and characterized from the symptomatic tomato and potato plants. Morphological characterization revealed heterogeneity in the different traits of the isolates, which were subsequently confirmed by molecular characterization and two different Alternaria spp. viz. A. solani and A. linariae were characterized. A multi-locus phylogenetic analysis was conducted to infer the taxonomic position of the isolates within Alternaria spp. The five conserved genome regions used to infer phylogenetic lineage and evolutionary relationship were the internal transcribed spacer (ITS), the translation elongation factor (TEF), the glyceraldehyde-3-phosphate dehydrogenase (GADPH), the major allergen Alt a1 (Alt a1) and the RNA-polymerase 2 (RPB2) genes. All A. linariae isolates were closely related and formed a clade to A. linariae isolated from the United States. Similarly, A. solani isolates were closely related to each other and formed an independent clade indicating their unique nature. Koch’s postulates were fulfilled for all the isolates. Among six different tested fungicides, aveet (azoxystrobin 5% + mancozeb 70%) inhibited the mycelial growth the most and saver (cymoxanil 5% + chlorothalonil 37%) the least. All the isolates infected tomato and potato leaves with varying severity except A. linariae isolate Egy-T2 was non-pathogenic on potato leaves, while the rest of A. linariae isolates were more aggressive. Here, we demonstrated that early blight in Egypt is caused by two different species of fungal pathogens, A. linariae and A. solani, and reported isolation of A. linariae from Egypt. © 2021 Friends Science Publishers

The importance of broccoli (Brassica oleracea var. italica) consumption has increased in recent years due to its significant amount of anticarcinogenic and antioxidant compounds, as well as its many vitamins. However, broccoli florets are a highly perishable product which rapidly senesce and turn yellow after harvest, resulting in losses in nutritional and bioactive compounds. Thus, in this study, we evaluated the effect of postharvest exogenous of salicylic acid (SA) and calcium chloride (CaCl2) and their combination on the quality of broccoli florets stored at 5 °C for 28 days to minimize the rapid senescence of broccoli florets. Samples treated with 2 mM SA alone or in combination with 2% CaCl2 showed lower weight loss and lower losses of chlorophyll content, vitamin C, phenolic compounds, carotenoids, flavonoids, and glucosinolates compared with the control samples. Additionally, antioxidant activity was maintained by either SA or SA + CaCl2 treatments while peroxidase activity was decreased. For higher quality and lower losses in antioxidant compounds of broccoli florets during refrigerated storage at 5 °C, SA + CaCl2 treatment could be helpful for up to 21 days.