Thumbnail Image

Theses

Browse

20201
Reset filters
Subject: Plant Pathology × Author: Halabi, Mohamad Hussam × End date: 2022 × Start date: 2020 × Type: Thesis × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    Molecular Characterization of potato viruses of North Eastern region of India
    (AAU, Jorhat, 2020-05) Halabi, Mohamad Hussam; Nath, P. D.
    The present research focused on the viral disease diversity of potato in the North-Eastern states of India. The potato producing potential of these states remain untapped even though the region provides suitable climatic and varied soil conditions. One of the significant challenges to potato cultivation is the high susceptibility of the crop to infections from disease-causing organisms such as bacteria, fungus, and viruses. The bacterial and fungal agents can be treated using suitable chemical control. However, viral infections remain without any control methods such as viricides. Moreover, the aphid pest, acting as vectors for viruses responsible for infection in potato, also remains at large in the region owing to the suitability of abiotic and biotic factors. The viral infections often cause reduced yield, under-sized tubers, lower production and are further transferred to crops propagated from the infected seed stocks. The farmers in North-East also deprived from lack of access to good seed material; hence the problem continues to intensify. Thus, in lieu of increasing problems, the present research entailed towards molecular characterization of plant viruses infecting potato crops in the region. Additionally, the phylogenetic analysis was also undertaken to study the evolutionary relationships shared by the viruses with other isolates across India. The efficacy of suitable methods was also assessed in acting as a quick diagnostic of viruses in infected plants. The investigation initiated in the potato fields itself surveyed for infected plants, through visual identification of symptomatology. Following the identification of infected plants, the collection procedures were performed, wherein the plant material was stored in cold boxes and maintained at low temperatures to preserve integrity. The serological Double Antibody Sandwich – Enzyme-linked Immunosorbent Assay (DAS-ELISA) was employed for confirmation of the presence of different viruses using suitable antibodies. Post the DAS-ELISA, the molecular techniques of Reverse transcription-polymerase Chain Reaction (RT-PCR), RT- Loop-mediated Isothermal Amplification (RT-LAMP), Multiplex-PCR, and Touch-Down PCR were employed. RT-PCR technique was employed to confirm the presence of virus infections. Other techniques of RT-LAMP, Multiplex PCR, and TD-PCR were employed to assess and compare the sensitivity of RT-PCR techniques. Further, The National Center for Biotechnology Information NCBI Blast tools, multiple sequence alignment, and techniques of Phylogenetic tree construction were used for studying phylogenetic clusters. The results showed the high prevalence of Potato leafroll virus (PLRV) and Potato virus Y (PVY), with the highest prevalence of viral infection in the Shillong region of Meghalaya. The RT-PCR amplification and agarose gel electrophoresis confirmed the presence of PVY, PLRV, Potato virus X (PVX), Potato virus M (PVM), Potato virus S (PVS) and Alfalfa mosaic virus (AMV) in the potato fields ofNorth-east India. Also, different strains of the PVY virus, namely PVYO, PVYN, and PVYNTN, were also confirmed. In the present study AMV infection on potato was detected and identified for the first time in India. In terms of comparative sensitivity and efficacy, the RT-LAMP assay was found to exhibit high efficacy as compared to RT-PCR. The phylogenetic clustering showed the relationship shared among the different isolates pan-India, while the AMV isolates shared a close relationship with virus isolates from Iran. The findings from the study contributed to the present literature available for potato virus prevalence in North-East India. Also, the identification of the AMV virus also paves the way to novel research into pathways leading to infection in India. Such knowledge related to specific potato varieties can help improve intelligent breeding of the improved potato varieties for the better cultivar. Future plans of the Indian authorities to boost the agriculture and farmer’s income for a better future need to be supplemented with better technologies. It is imperative to catch the infections at early stages to avoid the use of infected seed stock produced locally for the propagation of crops in future growing seasons. This could be achieved using sensitive techniques for early diagnosis in the future, of which High-throughput sequencing can form an important part.