A. Samad

Emerging threats of begomoviruses to the cultivation of medicinal and aromatic crops and their management strategies

Begomoviruses (family Geminiviridae) are responsible for extreme yield reduction in a number of economically important crops including medicinal and aromatic plants (MAPs). Emergence of new variants of viruses due to recombination and mutations in the genomes, modern cropping systems, introduction of susceptible plant varieties, global trade in agricultural products, and changes in climatic conditions are responsible for aggravating the begomovirus problems during the last two decades. This review summaries the current research work on begomoviruses affecting MAPs and provides various traditional and advanced strategies for the management of begomoviruses and vector in MAPs.

In silico and in vitro Studies on Begomovirus Induced Andrographolide Biosynthesis Pathway in Andrographis Paniculata for Combating Inflammation and Cancer

Andrographolide and neoandrographolide are major bioactive molecules of Andrographis paniculata, a well‐known medicinal plant. These molecules exhibited varying degrees of anti‐inflammatory and anticancer activities in‐vitro and in‐vivo. Role of begomovirus protein C2/TrAP in biosynthesis of andrographolide was identified through molecular modeling, docking and predicted results were substantiated by in vitro studies. Homology molecular modeling and molecular docking were performed to study the binding conformations and different bonding behaviors, in order to reveal the possible mechanism of action behind higher accumulation of andrographolide. It was concluded that C2/TrAP inhibit the activation of SNF1‐Related Protein Kinase‐1 (SnRK1) in terpenoid pathway and removes the negative regulation of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGR) by SnRK1, leading to higher accumulation of andrographolide and neoandrographolide in begomovirus infected plants. The binding site residues of SnRK1 docked with C2/TrAP were found to be associated with ATP binding site, substrate binding site and activation loop. Predicted results were also validated by HPTLC. This study provides important insights into understanding the role of viral protein in altering the regulation of biosynthesis of andrographolide and could be used in future research to develop biomimetic methods for increasing the production of such phytometabolites having anti‐cancerous and anti‐inflammatory properties.

Molecular and biological characterization of begomoviruses infecting Andrographis paniculata and their genetic recombination lineage

Begomoviruses infect a wide range of plant species and are emerging as one of the most detrimental pathogens. Recombination has led to the evolution and emergence of new species of begomoviruses that are better adapted to new hosts. With the development of computational recombination detection programs, better detection methods and increased availability of complete genome sequences in the database, it has become easier to identify recombination events. Andrographis paniculata is an important medicinal plant and known for the synthesis of various metabolites of high pharmaceutical value. In a recent field survey, a new strain of begomovirus infecting A. paniculata was discovered and full genome analysis revealed it to be different from the two isolates of begomoviruses reported earlier on this plant. Recombination Detection Program and SimPlot analysis showed the inter-species recombination in these begomoviruses infecting A. paniculata, while no recombination was detected in the previous isolates of these viruses. This study highlights the diversity of begomoviruses infecting A. paniculata in nature and also analyzes the role of recombination events responsible for the emergence of new begomovirus isolates/strains.