Muhammad Naeem Sattar

Geminiviruses, members of the Geminiviridae family characterized by their unique twinned icosahedral particles, pose a significant threat to global agriculture. Geminiviruses infest numerous crops such as tomatoes, cassava, cotton, and beans that result in huge losses to agriculture as well as in matters related to food security, more so in tropical and subtropical areas. The complex interplay between geminiviruses and their hosts is an intriguing but complex research area, ranging from molecular to cellular to ecological intersections. This Research Topic, "Interactive Dynamics of Geminiviruses with Host Plants", compiled by Drs. Muhammad Naeem Sattar, Zahir Ali, and Jesus Mendez-Lozano, included seven research articles and one review article. The articles in this Research Topic address different facets in relation to geminivirus interactions with their hosts. These discussed the complex relationship between geminiviruses with their plant hosts ranging from their efficient diagnosis, functional characterization to controlling them efficiently. Initial detection of geminiviruses often relies on observing characteristic symptoms in infected plants, such as leaf curling, mosaic patterns, and stunting. However, molecular approaches play an important role in definite identification as well as complete characterization. Atik and Paylan (2023) highlights the importance of seed testing and updating quarantine lists to control various viral pathogens. They identified the presence of tobacco mosaic virus (TMV) in 12% of the seeds, tomato mosaic virus (ToMV) in 23%, and cucumber mosaic virus (CMV) in 8% of the seeds, including instances of mixed infections. The findings underscore the necessity for developing robust seed health testing and the use of new generation diagnostics tools to effectively manage and control viral diseases. This was further highlighted by the findings from Sattar et al. (2024). The research discovered several distinct begomoviruses in the Al-Ahsa region of Saudi Arabia using high-throughput sequencing technique. They further highlighted the importance of continuous disease monitoring and understanding the evolutionary dynamics of begomoviruses to provide crucial information for effective disease management. The key findings of Yoboué et al. ( 2025) revealed specific alternative weed hosts that show diverse interactions with different cassava mosaic begomoviruses (CMBs) species, suggesting their key role in the emergence of new viruses in cassava. Several studies focus on the role of Bemisia tabaci, the whitefly vector, in shaping virus evolution and spread. The diversity of B. tabaci biotypes and their varying transmission efficiencies underscore the importance of vector biology in geminivirus epidemiology. Using RNA interference (RNAi) technique, Thesnim et al. ( 2023) identified TLR3 and TOB1 as potentially new genetic targets that could help control B. tabaci populations and reduce the transmission of chili leaf curl virus (ChiLCV). Other contributions examine the genetic and epigenetic changes in host plants during infection, providing insights into how viruses manipulate host gene expression and chromatin structure to their advantage.Geminiviruses are masters of manipulation, exploiting host cellular machinery to replicate and spread. The small, single-stranded DNA genomes of geminiviruses and their associated DNAsatellites encode a limited number of proteins, yet these proteins exhibit remarkable functional versatility. Viral proteins such as TrAP interact with host factors to hijack the plant's transcriptional and replication machinery. Meanwhile, proteins like C4 and V2 play critical roles in suppressing host immune responses, including RNA silencing and hormone-mediated defenses. Understanding these interactions at the molecular level is crucial for developing targeted strategies to disrupt viral infection cycles. Gupta et al. ( 2022) discovered a previously unknown βV1 protein, originating from the radish leaf curl betasatellite (RaLCB). This protein functions as both an elicitor, inducing a hypersensitive response (HR) that causes cell death in plants, and a virulence factor that may promote viral infection by interacting with the replication enhancer protein (AC3) of the helper virus within the nucleus. They highlighted that betasatellites associated with begomoviruses can encode proteins that actively contribute to disease development not only by enhancing viral replication but also by directly triggering plant defense responses that ultimately cause damage. This highlights the complex ways in which these viral components manipulate host plants to their advantage. Host plants, on the other hand, are not passive victims. They have evolved sophisticated defense mechanisms to detect and counteract viral infections. Siskos et al. ( 2023) identified the host plant's DNA Primase Large subunit (PRiL) as a crucial factor required for the replication of geminiviruses. Resistance to tomato leaf curl New Delhi virus (ToLCNDV) in melon was found to be consistently associated with a specific mutation in the PRiL gene. Furthermore, silencing the PRiL gene in Nicotiana benthamiana significantly reduced the levels of three different geminiviruses, confirming PRiL's essential role in their multiplication. The study proposes a model where PRiL, like its function in host DNA replication, helps generate the initial RNA primer needed for the conversion of the viral single-stranded DNA into the double-stranded form, a critical first step in geminivirus replication. Understanding such interactions may unveil new paths for resistance development to these common and destructive plant viruses by targeting this particular host protein.Integrated strategies are crucial for combating geminiviruses, as highlighted in this Research Topic. Traditional methods, such as breeding for resistance, have shown promise but are often undermined by the rapid evolution of viral strains....

The whitefly-transmitted begomoviruses (family Geminiviridae) infect dicotyledonous plants and occur in tropical and sub-tropical regions. Although most commonly found in herbaceous plants, recently begomoviruses have increasingly been identified in woody plants. Leaf samples from five mulberry (Morus alba L.) plants with leaf yellowing and curling symptoms were collected in Lahore (Pakistan) and shown by PCR to be associated with a begomovirus, an alphasatellite and a betasatellite. The complete sequences of two begomovirus clones, as well as an alphasatellite clone and a betasatellite clone, were determined. The begomovirus clones were shown to be isolates of ageratum enation virus (AEV), a virus most commonly identified in weeds but increasingly being identified in crops such as tomato, soybean and fenugreek. Analyses of the sequences of the alphasatellite and betasatellite clones showed them to be isolates of Guar leaf curl alphasatellite and Papaya leaf curl betasatellite, respectively. Both the virus and the alphasatellite sequences showed evidence of a recombination. This is the first report of the weed-infecting monopartite begomovirus AEV, and associated satellites, infecting the woody plant mulberry.

The genetic modifications through breeding of crop plants have long been used to improve the yield and quality. However, precise genome editing (GE) could be a very useful supplementary tool for improvement of crop plants by targeted genome modifications. Various GE techniques including ZFNs (zinc finger nucleases), TALENs (transcription activator-like effector nucleases), and most recently clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 (CRISPR-associated protein 9)-based approaches have been successfully employed for various crop plants including fruit trees. CRISPR/Cas9-based approaches hold great potential in GE due to their simplicity, competency, and versatility over other GE techniques. However, to the best of our knowledge no such genetic improvement has ever been developed in date palm—an important fruit crop in Oasis agriculture. The applications of CRISPR/Cas9 can be a challenging task in date palm GE due to its large and complex genome, high rate of heterozygosity and outcrossing, in vitro regeneration and screening of mutants, high frequency of single-nucleotide polymorphism in the genome and ultimately genetic instability. In this review, we addressed the potential application of CRISPR/Cas9-based approaches in date palm GE to improve the sustainable date palm production. The availability of the date palm whole genome sequence has made it feasible to use CRISPR/Cas9 GE approach for genetic improvement in this species. Moreover, the future prospects of GE application in date palm are also addressed in this review.

Cotton leaf curl disease (CLCuD), the most complex disease of cotton, is a major limiting biotic factor to worldwide cotton productivity. Several whitefly-transmitted monopartite begomoviruses causing CLCuD have been characterized and designated as CLCuD-associated begomoviruses. Despite of being reported over 100 years ago in Africa, CLCuD became economically pandemic causing massive losses to cotton production in Pakistan and India during past couple of decades. In Asia, cotton has faced two major epidemics during this period viz. “Multan epidemic” and “Burewala epidemic.” The “Multan epidemic” era was 1988–1999 after which the virus remained calm until 2002 when “Burewala epidemic” broke into the cotton fields in Indo-Pak subcontinent, till 2013–2014. However, both the epidemics were caused by monopartite begomovirus complex. Similarly in Africa, Cotton leaf curl Gezira virus with associated DNA-satellites causes CLCuD. Quite recently, in the Old World (both Asia and Africa), bipartite begomoviruses have started appearing in the areas under cotton cultivation. Under such aggravated circumstances, it seems we are heading toward another epidemic of CLCuD in the Old World. Here we articulate the causes and potential emergence of the third epidemic of CLCuD in Asia. The current situation of CLCuD in Asia and Africa is also discussed.

Leaf samples from Malva parviflora plants exhibiting vein yellowing and chlorosis were collected during 2013–14 from Lahore, Pakistan and analysed for the presence of begomovirus and associated DNA satellites through PCR and subsequent sequencing. The identified full-length begomovirus genome shared maximum nucleotide (nt) sequence identity at 92.5% with Hollyhock leaf curl virus (HoLCV), representing a new strain, which was tentatively designated as HoLCV-Mal. The betasatellite shared maximum nt sequence identity (92.8%) with Kenaf leaf curl betasatellite (KLCuB) and represents a new isolate of KLCuB. The two identified alphasatellites were 86% identical to each other and shared maximum nt sequence identities at 94.3 and 93.2% with Ageratum conyzoides symptomless alphasatellite (ACSLA) and Ageratum yellow vein India alphasatellite (AYVIA), respectively. Thus, these are the new isolates of ACSLA and AYVIA identified from M. parviflora in Pakistan. To the best of our knowledge, this is the first report of a complete monopartite begomovirus complex from M. parviflora in Pakistan.