Muhammad Azmat Ullah Khan

Risk assessment of Bt crops on the non‐target plant‐associated insects and soil organisms

Transgenic plants containing Bacillus thuringiensis (Bt) genes are being cultivated worldwide to express toxic insecticidal proteins. However, the commercial utilisation of Bt crops greatly highlights biosafety issues worldwide. Therefore, assessing the risks caused by genetically modified crops prior to their commercial cultivation is a critical issue to be addressed. In agricultural biotechnology, the goal of safety assessment is not just to identify the safety of a genetically modified (GM) plant, rather to demonstrate its impact on the ecosystem. Various experimental studies have been made worldwide during the last 20 years to investigate the risks and fears associated with non-target organisms (NTOs). The NTOs include beneficial insects, natural pest controllers, rhizobacteria, growth promoting microbes, pollinators, soil dwellers, aquatic and terrestrial vertebrates, mammals and humans. To highlight all the possible risks associated with different GM events, information has been gathered from a total of 76 articles, regarding non-target plant and soil inhabiting organisms, and summarised in the form of the current review article. No significant harmful impact has been reported in any case study related to approved GM events, although critical risk assessments are still needed before commercialisation of these crops.

In-Silico Determination of Insecticidal Potential of Vip3Aa-Cry1Ac Fusion Protein Against Lepidopteran Targets Using Molecular Docking.

Study and research of Bt (Bacillus thuringiensis) transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac) insecticidal protein and vegetative insecticidal protein (Vip3Aa) have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN) and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua, and Spodoptera litura) revealed that the Ser290, Ser293, Leu337, Thr340, and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein.

Molecular and Biochemical Characterization of Cotton Epicuticular Wax in Defense Against Cotton Leaf Curl Disease

BACKGROUND Gossypium arboreumis resistant to Cotton leaf curl Burewala virus and its cognate Cotton leaf curl Multan beta satellite (CLCuBuV and CLCuMB). However, the G. arboreum wax deficient mutant (GaWM3) is susceptible to CLCuV. Therefore, epicuticular wax was characterized both quantitatively and qualitatively for its role as physical barrier against whitefly mediated viral transmission and co-related with the titer of each viral component (DNA-A, alphasatellite and betasatellite) in plants. OBJECTIVES The hypothesis was the CLCuV titer in cotton is dependent on the amount of wax laid down on plant surface and the wax composition. RESULTS Analysis of the presence of viral genes, namely alphasatellite, betasatellite and DNA-A, via real-time PCR in cotton species indicated that these genes are detectable in G. hirsutum, G. harknessii and GaWM3, whereas no particle was detected in G. arboreum. Quantitative wax analysis revealed that G. arboreum contained 183 μg.cm-2 as compared to GaWM3 with only 95 μg.cm-2. G. hirsutum and G. harknessii had 130 μg.cm-2 and 146 μg.cm-2, respectively. The GCMS results depicted that Lanceol, cis was 45% in G. harknessii. Heptadecanoic acid was dominant in G. arboreum with 25.6%. GaWM3 had 18% 1,2,-Benenedicarboxylic acid. G. hirsutum contained 25% diisooctyl ester. The whitefly feeding assay with Nile Blue dye showed no color in whiteflies gut fed on G. arboreum. In contrast, color was observed in the rest of whiteflies. CONCLUSIONS From results, it was concluded that reduced quantity as well as absence of (1) 3-trifluoroacetoxytetradecane, (2) 2-piperidinone,n-|4-bromo-n-butyl|, (3) 4-heptafluorobutyroxypentadecane, (4) Silane, trichlorodocosyl-, (5) 6- Octadecenoic acid, methyl ester, and (6) Heptadecanoicacid,16-methyl-,methyl ester in wax could make plants susceptible to CLCuV, infested by whiteflies.

An overview of phytochrome: An important light switch and photo-sensory antenna for regulation of vital functioning of plants

Abstract Plants are the primary source of nutrition and essential to maintain life on earth. They have evolved very delicate and advanced photo-sensory antennae to sense their outer environment and transduce the received information for their growth and development accordingly. This “light switch” phenomenon of plants has slowly being unraveled and various plant photoreceptors, their role in downstream molecular signaling, mutual interaction, response to circadian cycle and light signals have been discovered. The photosensory antennae in plants; phytochromes, cryptochromes and phototropins play a very crucial role in sensing the ambient light intensities. By direct interaction with the environment through these photosensory antennae, plants shift their homeostasis to regulate their growth and development. The phytochrome light receptors of plants are responsive to R/FR light and by inducing signaling pathways, trigger the physiological responses such as germination and flowering. The phytochromes also directly contribute to plant development by affecting its photosynthetic rate. To elucidate the role of phytochromes in plant metabolism, this review will focus on the importance of phytochromes, their mechanism of action and their application as an emerging field in plant biology.

A Novel approach to study relationship between Cotton leaf curl virus (CLCuV) and Beta satellites

Cotton is very important cash crop of Pakistan and due to non-motile nature of the plants it is susceptible to different kinds of biotic and abiotic stresses. Lethal threat to cotton is cotton leaf curl virus (CLCuV) which belongs to family Geminiviridae and genus Begomovirus. Geminiviridae is often associated with sub viral agents called DNA satellites. These small pathogenic viruses which are transmitted by insects are responsible for various diseases in cotton crop. These defective interfering particles are associated with the infection like Begomovirus which is having monopartite and bipartite genomes. Our study is concerned with the DNA ß or betasatellite component of cotton leaf curl virus which is playing a tender role in cotton crop damage. Plants positive for betasatellites were confirmed for this study first by using specific primers. Then viral titre of full length virus or original virus was identified by using molecular techniques like southern blotting and real time PCR. After the detection of defective virus by southern blotting correlation study has been done between defective betasatellites and cotton leaf curl virus effected plants. Plants containing different symptoms were used in this study. Viral titers for different plants was compared with the positive plants for betasatellites. This correlation study between betasatellites and CLCuV depicts the role of betasatellites in the symptom advancements and their number is higher in highly affected plants. If infection is acute then number of betasatellites is higher. Our study helps to focus on the need to investigate another class of defective virus (alphasatellites) and their role in the infection. 230

Science Behind Cotton Transformation

The introduction of foreign genes into plant has made possible to bring out desired traits into crop of our own interest. With the advancement in cell biology, regeneration of plants from single cell and advent of different procedures for gene transformation to the plants have opened new avenues for the efficient and applicable implementation of biotechnology for the modifications of desired crop characteristics. Identifications and isolation of different genes for various traits from different organisms have made possible to get the crop plants with modified characters. Over time improvement has been made in transformation technology depending upon the crop of interest. The efficiency of plant transformation has been increased with advances in plant transformation vectors and methodologies, which resulted in the improvement of crops. A detailed discussion on advanced techniques for genetic modification of plants with their handy use and limitation has been focused in this chapter.