Standardizing Protocol for Developing Pure Inoculum of Leaf Crinkle Pathogen in Blackgram [Vigna Mungo (L.) Hepper] For Further Characterization

Abstract

Blackgram [Vigna mungo (L.) Hepper] or urdbean is one of the most important leguminous crops cultivated in India, Pakistan and South-East Asian countries. The crop is known to be affected by various biotic and abiotic stresses. Among the biotic factors, Urdbean Leaf Crinkle Disease (ULCD) is an economically significant one that has devastated crops in major blackgram cultivating regions. ULCD causes severe crinkling, rugosity of lamina, stunting of plants and malformation of buds inflicting heavy yield losses. Nevertheless, the disease was reported many decades ago and resulted in economic damage to the crop throughout all the seasons; the disease was reported many decades ago and resulted in economic damage to the crop throughout all the seasons; the causal agent of the disease is still unknown. In order to find the etiology and characterize at the molecular level, state-of-the-art technology, viz., Next Generation Sequencing / High Throughput Sequencing, has to be employed. Due to the occurrence of ULCD at field level as mixed infection along with other major viruses infecting blackgram like yellow mosaic, leaf curl, stem necrosis etc., the maintenance of pure inoculum under glasshouse conditions is an essential prerequisite. In the present study, protocol for modified seed sprout abrasion method was explained that helps in maintenance of pure inoculum of ULCD infected blackgram plants under glasshouse conditions in which the symptoms started appearing 20 days post inoculation (DPI) and the disease incidence was up to 88%. Further investigation has proved this modified sprout seed abrasion method as efficient protocol to obtain transmission at higher levels at the earliest.

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