Antiserum production, biological and serological detection of Cucurbit yellow stunting disorder crinivirus (CYSDV) in Egypt.

Cucurbit yellow stunting disorder crinivirus (CYSDV) causes significant yield losses in the field- and greenhouse grown cucurbits. In Egypt, it has become serious problems for open fields and greenhouses production of all cucurbit (Family: Cucurbitaceae) plants i.e., cantaloupe, cucumber, pumpkin, squash and watermelon. Inspection of (Cucumis sativus L.) cv. El-Safa plants grown in the fields exhibited extensive interveinal yellowing and green veins are most apparent on the older leaves and reduced plant vigor, whereas new growth appears normal. Whilst in the greenhouse trail, CYSDV-infected plants showed prominent interveinal yellowing typical to naturally infected ones, 3-4 weeks after whiteflies inoculation. In whiteflies transmission experiments, the maximum transmission efficiency (86%) was recorded, when applying fifteen insects in each treatment to transmit CYSDV after 48hr for both AAP and IAP. The highest percentages reached to 93 and 86% respectively, in CYSDV-naturally infected and whiteflies inoculated squash cv. Escandarani plants. The lowest percentages were recorded in watermelon and pumpkin being 6% and 13% respectively, in natural infection and whiteflies transmission. In Egypt, CYSDV infects noncucurbit plants belonging to the families Amaranthaceae, Chenopodiaceae, Leguminosae (Fabaceae), Malvaceae and Solanaceae. The purified virus has Amax at 260 and Amin at 240 of 1.3. Virus yield was 20mg/200g of fresh weight. Evalution of cucumber varietal reaction against CYSDV-infection using the induced antibody (CYSDV-Pab) in DAS-ELISA, after 1h and overnight incubation with paranitrophenyl phosphate (PNPP) substrate gave nearly similar results. The induced polyclonal antibody (CYSDV-Pab) was also evaluated in detecting CYSDV antigen in the infected plants through serological tests i.e., tissue and dot blot immuno-printing assay (DBIA&TBIA, respectively) in naturally-and whiteflies infected plants. Both DBIA and TBIA proved to be effective in differentiating between healthy and infected samples, faster, sensitive and reliable techniques for the detection CYSDV in cucumber leaf petioles.