تقييم بعض التراكيب الوراثية والمستحضر الاحيائي النانوي والمبيدات الكيميائية في مكافحة بعض الفايروسات المشخصة بتقانة Next Generation Sequencing في نبات الباميا

Evaluation of Some Genotypes, Nano-Biological Formulation, and Chemical Insecticides in Controlling Viruses Identified by Next Generation Sequencing in Okra Plants

This study aimed to identify the virus community (virome) affecting okra crops and evaluate an integrated pest management strategy against them, which includes genetic varieties, Nano biopreparation, and insecticides.
After collecting infected plant samples from different fields of okra crops, Next-Generation Sequencing (NGS) technology using the Metatranscriptomics method was employed to fully identify and characterize the viruses infecting okra plants. The bioagent Trichoderma koningiopsis was used to produce nanoparticles of zinc oxide (ZnO) as Nano biopreparation, which was used alongside genetic varieties and insecticides in an integrated pest management program for controlling the viruses and whitefly insects affecting okra crops.
The results of the NGS data analysis revealed the presence of several viruses and viral satellites alongside one fungal virus. These included the Cotton leaf curl Gezira virus (CLCuGeV), identified through multiple contiguous overlapping sequences similar to the reference genome of the virus in plant samples, with raw read sequences coverage of the full genome 100% and a similarity rate of 97.7%, with a copy number of 413.7 X. Consequently, the full genome of this virus was reported in the GenBank database under the name Cotton leaf curl Gezira virus isolate Okra/Iraq-1 with the accession number PP837748.1. The results also indicated the presence of the viral satellites Cotton leaf curl Gezira alphasatellite (CLCuGA), Cotton leaf curl Gezira betasatellite (CLCuGB), and Okra leaf curl alphasatellite (OLCuA), with multiple contiguous overlapping sequences similar to their genomes, with coverage rates of 100% for all of them, and similarity rates ranging from 93% to 100%. These three genomes were documented in GenBank with the following names and accession numbers: Cotton leaf curl Gezira alphasatellite isolate Okra/Iraq-1 (PP837749.1), Cotton leaf curl Gezira betasatellite isolate Okra/Iraq-1 (PP837750.1), and two isolates for Okra leaf curl alphasatellite isolate Iraq-1+2 (PP779765.1) and (PP839930.1), respectively, noting that the latter satellite is recorded for the first time in Iraq. The results also showed the presence of the Cotton bunchy top virus (CBTV), with coverage and similarity to the reference genome of 85.4% and 97.3%, respectively, and an average copy number of 12.1 X. The full genome of this virus was deposited in the NCBI-GenBank under the name Cotton bunchy top virus isolate Iraq-1 with the accession number PP680224.1, marking its first record in Iraq.
In addition to these viruses identified in this study, the fungal virus (Mycovirus) Erysiphe necator-associated virus (EnVS) was identified by finding multiple contiguous overlapping sequences similar to a part of the reference genome. The Iraqi isolate had a high similarity rate of 93.48% with the type EnVS-1, leading to the documentation of the RdRp gene of the Iraqi isolate in the GenBank under the name Erysiphe necator -associated virus 1 isolate Iraq-1 with the accession number PP352232.1.
Moreover, the process of manufacturing a Nano biopreparation was accomplished for the first time in Iraq using the bioagent Trichoderma koningiopsis and zinc oxide (ZnO). The nanoparticles were of diverse sizes and were loaded onto the surface of the bioagent’s spores. They were successfully used in field experiments.
Finally, field experiment results confirmed that the integrated pest management method was preferable for reducing the number of whitefly insects and the disease severity percentage of the virus infection. The best-integrated treatments included planting the genetic variety Hort-5 and applying the Conan insecticide with either the bioagent alone or the Nano biopreparation alone, reducing the disease severity percentage to 31.0% and 33.3%, respectively, and the number of whitefly insects to an average of 9.8 and 8.5 insects, respectively. These were followed by the treatment of planting the genetic variety Hort-5 and applying the Actara insecticide and the Nano biopreparation, with a disease severity percentage of 33.3% and an average number of insects reaching 9.4. Compared with the control treatments that involved planting the genetic varieties only, which showed disease severity percentage and number of whitefly insects for the Hort-5 variety of 50.7% and 12.1 insects, respectively, while the Abeer variety had 73.3% and 16.4 insects, respectively.