Cotton Leaf Curl Virus (CLCuD/Begomovirus): Evolutionary Dynamics, Vector Transmission Biophysics, and 2026 Reverse-Genetics Infectious Clone Diagnostics

The production integrates high-definition field cinematography, living vector kinematics, real-time Electrical Penetration Graph (DC-EPG) signal waveforms, rolling-circle DNA replication (RCR), and recent reverse-genetics breakthroughs from ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi.</p><p><br></p><p dir="ltr">Chapters & Scientific Scope</p><ol><li>Epidemic Trajectory & Evolutionary Genesis (1912–1993): Historical records from Nigeria (1912) and the Sudan Gezira Scheme (1924) through the devastating 1993 Multan epidemic in northern India and Pakistan, which decimated elite cultivar S-12 (>9 million bales lost).

Unmasking the monopartite Begomovirus (CLCuMuV, ~2.75 kb) and circular ssDNA betasatellite (CLCuMB, ~1.35 kb) complex encoding the master pathogenicity suppressor protein βC1.</li><li>Molecular Silencing & Capsid Biophysics: Cryo-EM geminate virion architecture (twin incomplete T=1 icosahedra, 22×38 nm; 22 pentameric capsomers) and ICAR-IARI insights into βC1-mediated dual suppression of Post-Transcriptional (PTGS) and Transcriptional Gene Silencing (TGS), host methyltransferase (SAHH) inhibition, and 26S ubiquitin-proteasome disruption.</li><li>2001 Burewala Breakdown & Recombination Genetics: Multi-year field surveillance across Punjab, Haryana, and Rajasthan documenting the inter-species crossing over of CLCuMuV × CLCuKoV into CLCuBuV, and the pathognomonic 99-bp deletion within the CLCuMB βC1 ORF (118 aa → 93 aa), evading host immune surveillance in resistant cultivars (FH-901, CIM-1100, RS-2013).</li><li>Vector Transmission Biophysics & DC-EPG: Bionomics of the predominant indigenous whitefly biotype *Bemisia tabaci* Asia II-1, GroEL endosymbiont capsid protection against hemolymph proteases, cibarial suction pumping (3–5 Hz), and micro-electrometry of stylet penetration waveforms: Pathway C (intercellular probing), Potential Drop (pd, –105 mV intracellular puncture), Phase E1 (salivary injection / phloem inoculation), and Phase E2 (sustained phloem ingestion / acquisition).</li><li>Histopathology & ICAR-CICR Resistance Breeding: Ectopic homeobox WUSCHEL/KNOX gene reactivation driving abaxial foliar enations and 100% boll failure, contrasted with durable introgression of immunity from diploid Asiatic desi cotton (*Gossypium arboreum*) into elite donor germplasm lines (GVS-8, GVS-9).</li><li>May 2026 Infectious Clones & CRISPR Frontiers: Comprehensive presentation of the reverse-genetics milestone published in *Physiology and Molecular Biology of Plants* (May 2026, 32(5): 1091–1105, DOI: 10.1007/s12298-026-01752-0) by M. Elangovan, S. Godara, U.K. Bhattacharyya, K.K. Biswas et al. Details the binary vector pCAMBIA2301 harboring a 1.4-mer partial tandem dimer of *Begomovirus gossypikokranense* (CLCuKoV) and a 2.0-mer complete dimer of *Betasatellite gossypimultanense* (CLCuMB), agroinoculation fulfilling Koch's postulates on cotton cvs.