Laboratory Diagnosis of COVID-19 Infection: Current Issues and Challenges: An Indian Perspective

COVID-19, a disease caused by SARS-CoV-2 has become a public health emergency affecting morethan 215 countries worldwide. It originated from Wuhan district of China and in a very short span of time, it has spread rapidlycausing millions of deaths worldwide. India reported its first case on 30thJanuary 2020 and since then the numbers have been increasing exponentially every day. As of 9thAugust 2020, India had recorded 21, 09,631 confirmed cases and 43,379 deaths. Because of the complex dynamics involved in its infection and immunity, proper diagnosis is imperative in order to unravel this ongoing mystery. It has clearly told us the importance of establishing and strengthening a strong network of molecular virology laboratories in the country enabling us to strengthen the diagnostic arm which is the first step in disease control. The addition of serological tests has helped in surveillance and also to estimate the overall burden of disease.

Do leaf surface characteristics affect Agrobacterium infection in tea [Camellia sinensis (L.) O Kuntze]?

The host range specificity of Agrobacterium with five tea cultivars and an unrelated species (Artemisia parviflora) having extreme surface characteristics was evaluated in the present study. The degree of Agrobacterium infection in the five cultivars of tea was affected by leaf wetness, micro-morphology and surface chemistry. Wettable leaf surfaces of TV1, Upasi-9 and Kangra jat showed higher rate (75%) of Agrobacterium infection compared to Upasi-10 and ST-449, whereas non-wettable leaves of A. parviflora showed minimum (25%) infection. This indicated that the leaves with glabrous surface having lower q (larger surface area covered by water droplet), higher phenol and wax content were more suitable for Agrobacterium infection. Caffeine fraction of tea promoted Agrobacterium infection even in leaves poor in wax (Upasi-10), whereas caffeine-free wax inhibited both Agrobacterium growth and infection. Thus, study suggests the importance of leaf surface features in influencing the Agrobacterium infection in tea leaf explants. Our study also provides a basis for the screening of a clone/cultivar of a particular species most suitable for Agrobacterium infection the first step in Agrobacterium-mediated genetic transformation.