Tahir Rehman Samiullah

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.

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.