Browsing by Author "Manju Elizabeth, P"

Now showing 1 - 4 of 4

Amplification and sequencing of spacer region between two tRNA genes and its flanking region in the chloroplast genome of Centella asiatica L.
(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2006) Manju Elizabeth, P; Rajmohan, K
The study entitled “Amplification and sequencing of spacer region between two tRNA genes and its flanking region in the chloroplast genome of Centella asiatica L.” was conducted at the Department of Plant Biotechnology, College of Agriculture, Vellayani, Thiruvananthapuram during 2005-2006 with the objective of isolating a spacer region and its flanking regions from the chloroplast genome of Centella asiatica to develop a species specific vector for the chloroplast transformation. Heterologous primers were designed based on the chloroplast genome sequences of Arabidopsis thaliana, Nicotiana tabacum and Panax ginseng using Pimer3 software for the spacer regions trnG-trnfMet, trnE-trnT, trnT-trnL and rps16-trnQ and were amplified on genomic DNA of Centella asiatica. The entire isolated regions were sequenced except trnT-trnL spacer region. All sequenced regions were subjected to BLASTN and BLASTX similarity search. The trnG-trnfMet spacer region (270bp) showed maximum similarity to the same region in Panax ginseng (GI: 51235292, AY582139.1) chloroplast genome. The spacer region between genes rps16 and trnQ (1749bp) showed maximum similarity to rps16 gene and its intron in Centella asiatica (GI: 6692894, AF110603.1) chloroplast genome and to rps16 gene, spacer region after rps16 and starting region of trnQ gene in Panax ginseng (GI: 51235292, AY582139.1) chloroplast genome. Primers for flanking regions of rps16-trnQ spacer were designed manually based on the primers of this spacer and the chloroplast genome of Panax ginseng. The right flanking region amplified (1582bp) with primers Hf and Hr showed maximum similarity to trnQ gene, spacer region after trnQ, psbK gene, spacer region after psbK and psbI gene in Panax ginseng chloroplast genome. The left flanking region of rps16-trnQ spacer sequence amplified (1227bp) with primer combination Ff and Fr showed similarity to rps16 gene, spacer region after trnK gene, trnK gene and spacer region after matK gene of Panax ginseng chloroplast genome. The sequence amplified (1089bp) with primers Gf and Fr showed similarity to rps16 gene, spacer region after trnK of Panax ginseng and to matK gene of Centella erecta (GI: 2281236, US8599.1). The spacer region between rps16 and trnQ gene and its flanking region isolated can be used in developing a Centella asiaticaL. specific vector for chloroplast transformation.
Genetic diversity of Dimocarpus longan Lour., in Southern Western Ghats
(Department of Forest Biology and Tree Improvement,College of Forestry, Vellanikkara, 2022) Devika, P S; Manju Elizabeth, P
Longan (Dimocarpus longan Lour.), is an important commercially cultivated fruit tree, belonging to the family Sapindaceae. It is commonly known as dragon-eye. In Kerala, it is known by the names chempoovam, mullai etc. It is widely cultivatedin many Asian countries like China, Thailand, and Taiwan etc. Recently many other countries including India, Sri Lanka etc. have started cultivating longan tree as a commercial fruit tree. Longan is used as a traditional medicine in China due to its high medicinal and nutraceutical value. The global demand for longan fruit has hiked rapidly due to its sweet taste and nutritional value. Fruit consist of a white edible juicy aril which is surrounded by a leathery pericarp. The fruit is rich in various bioactive polyphenols, vitamin C, volatile compounds, minerals, amino acids, proteins, fats, carbohydrates etc. Longan leaf, fruit pericarp, seed and pulp were used for extracting various polyphenols. Extracts from various parts of longan have shown pharmaceutical properties like antioxidance, anti-tyrosinase, anti-cancerous, anti-glycated, immunomodulatory activity, antihypertensive etc. Thus the importance of fruit can also be emphasized due to its richness in nutritional value. The longan tree is a subtropical fruit tree native to the southern regions of China and Indo-Burma. D. longan is indigenous to India's Western Ghats, ranging from Konkan to Tinnevelly. Other distributions in India include Eastern Bengal and Western Peninsular regions. In the Western Ghats region of Kerala, longan is a species widely distributed in evergreen forests. There is a small distribution in the semi-evergreen forests of Kerala as well. The diversity of indigenous longan populations in Western Ghats has never been studied before. In this study, morphological and genetic diversity of longan populations from six different locations in the Western Ghats regions of Kerala were selected. Among these six locations, three were located in the north of Palghat gap and three were in the South ii of Palghat gap. Morphological parameters like crown shape, branching pattern, tree height, tree girth, leaf length and leaf width was considered for studying the morphological diversity. Results from morphological traits revealed that the population from Meppadi region from north of Palghat gap stood different from other longan populations. Cluster analysis conducted using UGPMA method based on the morphological traits showed that population from Mankulam was closely related to the Meppadi population. The populations from six locations were divided into two major clusters. ISSR primers were used to investigate the genetic diversity existing among the six populations. 15 ISSR primers screened from total of 19 primers were used to amplify the DNA sample from different longan populations. Average polymorphism rate of 69.51% was observed. Matrix data was obtained and hierarchical dendrogram was produced using UGPMA method in NTsys pc 2.02 and DARwin software which clusters the populations into two major groups. Jaccard’s dissimilarity index was calculated using R software and the values ranged from 0.00 to 0.51. Genetic relation existing between the natural populations of longan in Kerala, cultivated longan cultivars and litchi were identified. Cluster analysis using UGPMA method pooled different populations into four major clusters and study proved that litchi is genetically more related to the cultivated longan variety rather than the wild populations. This is the first report on the molecular characterization of D. longan from Western Ghats regions in India. The results from this research study can provide valuable information to distinguish, classify and identify the origin of longan populations in India and can be applied for future breeding programs.
Genetic relations in Meliaceae family and diversity analysis in Swietenia marcophylla King accessions
(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2025-01-15) Nibin Antony, K; Manju Elizabeth, P
Regulation of long noncoding RNA(LNCRNA) in response to spike disease in santalum album Linn.
(Department of Forest and Tree Improvement, College of Forestry, Vellanikkara, 2024-08-06) Sreelakshmi Dhanesh.; Manju Elizabeth, P
Sandalwood (Santalum album Linn.), is listed as vulnerable on the IUCN Red List. The tree is highly priced for its aromatic heartwood and essential oil which is used for many medicinal purposes and perfumery. One of the major reason for decline in population is the Sandal Spike Disease (SSD) caused by a phytoplasma which often lead to the death of the plants. No effective measures for recovering diseased plants from the spike disease have been identified and removal of diseased trees from the field is considered as the usual method for controlling the spread of the disease. Many studies were carried out in agricultural crops and tree to elucidate the role of the lncRNA both in biotic and abiotic stress response. Identifying the spike responsive lncRNA and analysing the expression level of these lncRNA will help in developing management strategies for sandal spike disease. Reserve No. 52 of Marayoor sandal division is mostly infected with spike disease and is selected as the study location. Based on morphological characters observed in the field, 15 trees were marked as spike infected and 15 trees as non infected. Molecular level disease confirmation was carried out in these 30 selected samples using reported SSD I primer pair for 16sRNA for sandal spike phytoplasma. It was found that among designated 15 non infected trees, two were infected. Bimonthly observations on leaf area (cm2), leaf thickness (mm) and total chlorophyll (mg g-1) content were made. These morphological parameters were significantally varied between spike infected and non-infected trees. Earlier reported six phytoplasma responsive lncRNAs were amplified in the genomic DNA of sandalwood. Differential expression of these six lncRNAs were analyzed by Q RT PCR method and 2–∆∆Ct method. Among the lncRNAs analysed, TCONS_00021785, TCONS_00019890, TCONS_00004908 were down regulated and TCONS_00012735, TCONS_00033648, TCONS_00034613 were upregulated in the spike infected samples. In earlier studies, these phytoplasma responsive lncRNAs were reported 90 to play a key role in defense mechanism, photosynthesis, metabolism, stress resistance and cell signal transduction. Analysing the expression profile of spike responsive lncRNAs at regular interval in more number of trees will throw light on how the lncRNA is regulated on the progression of the sandal spike disease compared to non infected plants. Identification of more number of spike responsive lncRNA will be helpful in using as a biomarker for the early detection of spike disease, even if the symptom is not present in the plant. Understanding the role of these lncRNAs in defensive signaling pathway will help to regulate the pathway in desirable manner.