Research Journal of Biotechnology

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Vol. 14(12) December 2019

Inheritance of ascorbic acid and nature of gene action for nutritional traits in tomato

Chauhan V.B.S., Kumar R., Behera T.K., Yadav R.K., Kaur C., Choudhury H. and Verma A.K.

Page No: 1-7

Abstract: The objectives of this study were to cognize the inheritance of ascorbic acid and type of gene action controlling some nutritional traits in tomato. To understand the inheritance of ascorbic acid, high ascorbic acid (21.56 mg/100 g) cultivar Roma was crossed with low ascorbic acid (8.55 mg/100 g) cultivar cherry orange to develop F1 and F2 populations. The F2 population of the cross was segregated in ratio of 15:1 (15 high ascorbic acid: 1 low ascorbic acid) and indicated digenic inheritance with over-dominance of high ascorbic acid over low ascorbic acid. The implicitness of much variability in ascorbic acid content in tomato apparently raises the possibility of presence of multiple allelic series for major gene allied with ascorbic acid determination. To know the nature of gene action, cross Roma × Cherry Orange was used for studying the genetic parameters of nutritional traits.

Additive gene effects were found to be important in the inheritance of lycopene, ascorbic acid and viscosity. Dominant gene effects were important in the inheritance of viscosity. Concerning to the positive and significant epistatic gene effects, additive × additive was recorded for lycopene, titrable acidity and viscosity and dominance × dominance for ascorbic acid, total phenolics and total soluble solid. Complimentary epistasis was recorded in most of the studied traits such as lycopene, total phenolics, titrable acidity and total soluble solid while duplicate epistasis were recorded for ascorbic and viscosity.

Evaluation of molecular diversity in some Red sea parrotfish species based on mitochondrial 16S ribosomal RNA gene sequence variations

Saad Y.M., Shaikh Omar A.K.M. and Gharbawi W.M.

Page No: 8-21

Abstract:The evolution of parrotfishes including Scarus species in the Red Sea is unclear. The true phylogenetic relations among these fishes have remained problematic especially between the closely related taxa. Developing of molecular markers could be applied for detecting biodiversity and understanding the evolution in these aquatic biological resources. In this study, the capability of 16S rRNA gene system in identification of some parrotfish species (Scarus fuscopurpureus, S. ghobban, S. ferrugineus S. psittacus and Chlorurus sordidus) comparatively with other fishes belonging to two families (labridae and scaridae) was established.

DNA polymorphism and sequence conservation values were calculated for overall estimated sites and for each evaluated 16s r-RNA gene fragment. The phylogenetic relations that were reconstructed among evaluated fishes showed that fishes were clustered into unique groups. One of them is including 10 fish species belonging to family scaridae. The other fish species (20 species) were belonging to the family labridae. This study could be preliminary for the next comprehensive investigation which takes more molecular techniques, especially at the nuclear DNA for reconstructing the true phylogenetic relations among the evaluated fish taxa.

Chitosan-based in-vitro propagation of banana (Cv. Grand Naine) and its genetic uniformity assessment

Kandha Laxman, Kumar Rahul, Hembram Krushna C. and Bindhani Birendra Kumar

Page No: 22-29

Abstract:The right selection of explants with optimum regeneration potential is the most limiting step in the production of banana plants of stable genetic uniformity. To increase the survival rate of in-vitro propagated banana with stable genetic uniformity, a modified methodology is developed in this study. The fungal and bacterial contamination are the main hindrances in the production of tissue cultured plants. Few groups reported that chitosan (CS) is very effective in controlling general infections in tissue culture. The chitosan is also promoting the growth of explants by controlled release of nutrients and phytohormones. Rhizome and sucker explants were used as explants and regenerated successfully under the influence of BAP (8 mg/L), IAA (0.5 mg/L) and chitosan (25 mg/L). The rooting after shoot generation was induced by IBA (1 mg/L) in the growth media.

The plants were hardened successfully in the greenhouse with a survival rate of 90% in the sucker and 86% in the rhizome as well as 69% and 63% of both positive controls respectively. Random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) DNA molecular markers were used to assess the genetic uniformity of in-vitro regenerated plants of Musa paradisiacal (Grand Naine). There were 30 primer sets of RAPD and ISSR molecular markers used to screen the genetic uniformity of regenerated plants. Out of 30 primer sets, 10 sets of RAPD and 11 sets of ISSR produced a similar pattern of DNA bands. The result was confirmed by after more than three sets of experiments repeated in similar conditions. The amplified products were found monomorphic like all micro-propagated plants with the mother plant. The present optimized method may be helpful in the micro-propagation of other important banana cultivars.

Investigation of the producibility of the mannanase and phytase enzymes by Brevibacillus brevis (P14) and Brevibacillus borstelensis (P15) in the same conditions

Sadigh Shadi, Adiguzel Ahmet and Nadaroglu Hayrunnisa

Page No: 30-40

Abstract: In this study, the production of phytase and mannanase enzymes in the same medium was executed in a natural medium with Carob and Corn using free and immobilized Brevibacillus brevis (P14) and Brevibacillus borstelensis (P35) bacteria. For this purpose, after inoculating the test bacteria in different ratios of corn (10, 20, 30 and 40 g) and carob (10, 15 and 20 g) media (pH 7.0), the flasks were incubated at 55 oC for 24-48 hours. The florisil support material was first attached to the APTES and -NH2 groups to prepare the immobilization material. The intermediate arm was then formed with L-glutaraldehyde. The activated florisil support material was magnetized with nano- Fe3O4 compound and used for immobilization of bacteria. The immobilization experiments showed that both bacteria were immobilized at about 60% to the magnetite florisil nanoparticles prepared.

In consequence of the analysis, the immobilized forms of B. brevis and B. borstelensis bacteria inoculated into medium containing Carob and Corn natural carbon sources showed an increase in the phytase and mannanase enzyme production potentials in the same conditions by 59-81% compared to the free ones. This has shown us that the test strains of magnetite florisil nanoparticles can be used safely in many industrial areas, chiefly in food, agriculture, pharmaceutical and feed industries.

Annexin A2 mediated down regulation of BRCA1 in sporadic breast cancer

Bargale Anil Bapu, Shetty K. Jayaram, Shetty Praveenkumar, Suchetha Kumari N., Patil Vidya S. and Sarathkumar E.

Page No: 41-46

Abstract:Breast cancer is the leading cause of deaths in women worldwide. BRCA1 is known for its multiple vital functions in tumor suppressor activity. Recent reports had shown that the several genes are regulated by mRNA binding proteins. AnnexinA2 is a RNA binding protein which is highly expressed in basal BC where BRCA1 expression is very low or null. AnxA2 is highly expressed in the surface of human tumor cells and promotes cell migration and invasion by activating plasminogen and cleaving extracellular matrix. AnxA2 stimulates cell proliferation, angiogenesis and invasion and can be a prognostic indicator in human cancer.

BRCA1 and AnxA2 expression in TNBC tissue samples and different cell lines was analyzed by IHC, Western Blotting respectively. AnxA2 knock down/Knock in studies was conducted to demonstrate BRCA1 and AnxA2 expression. Immunohistochemistry analysis of TNBC paraffin embedded tissue specimens showed low BRCA1 and high AnxA2 expression and vice versa. These findings were studied by Knock in/Knock down experiments and validated by si-RNA mediated silencing of AnxA2, which leads to increased expression of BRCA1. In the present study, we showed that BRCA1 and AnxA2 are reciprocally regulated. AnxA2 down regulation could be attributed to the BRCA1 functioning and cell damage repair.

Computational characterization of lipoxygenase and hydroperoxide lyase enzymes and Real Time PCR-based expression analysis of their encoding genes in peanut under heat and drought stress

Anand Preeti, Singh Shaifali, Prajapati Gopal Kumar and Pandey Dev Mani

Page No: 47-57

Abstract:Peanut (Arachis hypogaea) is an important legume that is grown wide-reaching for its need as seed and oil. Currently efforts are being taken into consideration to increase shelf life, seed quality and odor quality of peanut oil under adverse condition. It is vital to understand gene regulation as well as their involvement in corresponding metabolic pathways. Here, we aim to study the enzymes as well as genes responsible for flavor and sensory attributes. Characterization of two proteins like lipoxygenase (Ahlox) and hydroperoxide lyase (Ahhpl) because of their involvement to flavor and odor attributes as well as expression of their encoding genes was performed. Phylogenetic tree analysis of enzymes was performed by using MEGA X, structure prediction by ITASSER, analysis of secondary structure by SOPMA, Ramachandran plot and analysis by PROCHECK while conserved domain was identified by using NCBI search tool.

Expression pattern of Ahlox and Ahhpl encoding genes (Ahlox and Ahhpl respectively) was performed using Real Time PCR. Phylogeny based evolutionary relationship, ITASSER based structure prediction having a model with high C-score and high confidence and Ramachandran plot by PROCHECK analysis having higher stability of the predicted Ahlox and Ahhpl proteins were observed. Conserved domain analysis indicated that Ahlox belongs to the lipoxygenase superfamily and Ahhpl belongs to the P450 superfamily. However, Ahlox and Ahhpl genes were found to be differentially expressed in ICR48 as well as ICGV91114 varieties under heat and drought stresses.

Virulence, cross infectivity and molecular characterization of Spilosoma obliqua MNPV from north India for Bihar hairy caterpillar management

Sujayanand G.K., Mohammad Akram, Nigam Ashish, Konda Aravind, Bhat Shripad, Sachan Deepak Kumar, Husain Raja and Pandey Sonika

Page No: 58-70

Abstract:The Bihar hairy caterpillar (BHC), Spilosoma obliqua Walker is a polyphagous insect infesting >100 crops. Heavy infestation of BHC was recorded in Uttar Pradesh, a northern state of India during January 2014. In the present investigation, BHC incidence was estimated along with its pathogen SpobMNPV incidence in the natural epizootic conditions. The BHC infestation was found to be in the range of 32-40 larvae/m2 in potato and 10 larvae/plant in pigeonpea. The SpobMNPV incidence ranged from 24% to 40%. Further transmission electron microscope studies revealed it as multiple nucleopolyhedrovirus (MNPV). The polyhedral occlusion bodies (POBs) were found to have irregular shape with a dimension of 0.466 μm  0.363 μm.

The LC50 and ST50 value of SpobMNPV against 3rd instar S. obliqua larvae was 4.46  105 POBs/ml and 72 h respectively. In an endeavor to characterize the SpobMNPV five genes (polh, lef 1, lef 2, lef 9 and p47) were cloned and sequenced. The analysis of these genes indicated close evolutionary relationship of SpobMNPV with Hyphantria cunea NPV and it belongs to α Baculovirus group I. Interestingly, the SpobMNPV was found to cross infect another Erebidae member commonly known as wollybear, Olepa ricini. We report a highly virulent α baculovirus (SpobMNPV) against BHC isolated from a natural epizootic. This promising bioagent has the potential for transforming into a novel bio-pesticide for the eco-friendly management of two agriculturally important insect pests.

Development and characterization of microsatellite markers from enriched genomic libraries in safflower (Carthamus tinctorius L.)

Usha Kiran Betha, Mobeen Shaik, Kadirvel P., Mukta N. and Senthilvel S.

Page No: 71-87

Abstract: Microsatellite markers are the ideal genetic markers for crop improvement. In this study, we developed and characterized a set of 200 genomic SSR markers in safflower, an important oilseed crop of the world. A microsatellite enriched genomic library was constructed from an Indian cultivar, A-1. A total of 750 SSR-positive clones was generated of which 617 were identified as unique sequences and sequencing of them revealed 238 SSR motifs. The SSRs are validated in a panel of 24 genotypes and found 42 polymorphic markers. The number of alleles ranged from 2 to 4 with an average of 2.7 with polymorphic markers.

The polymorphic information content (PIC) value ranged from 0.08 to 0.61 with an average of 0.33. A dendrogram based on the polymorphic SSR loci clearly indicated the genetic relationships among genotypes. The reported SSR markers would be useful for characterization of genetic diversity and trait mapping purposes in safflower.

Prevalence of urinary tract infections (UTI) and its etiological agents among pregnant woman at Qurrayat region

Bi Bi Zainab Mazhari and Mohammed H. Saiemaldahr

Page No: 88-91

Abstract: Urinary tract infection (UTI) is the most common medical complication of pregnancy together with anaemia and hypertension and it occurs approximately in 5% - 10% of all pregnancies. The present study determines the incidence of UTI and prevalence of uropathogens among pregnant women. During the study period from August 2018 to February 2019, 80 urine samples were analysed. UTI was diagnosed by growth of 105 CFU/ml of a urinary tract pathogen in culture of midstream urine samples. The isolated bacteria were identified by biochemical tests.

The results showed that 74.9% of pregnant women have UTI. E. coli was the most frequently isolated organism (48.3%) followed by Klebsiella sps (20%), Pseudomonas sps (6.6%) and Proteus sps (5%). Other pathogens isolated were Enterobacter (1.6%) and Enterococcus sps (1.6%). Of the variables examined, the highest prevalence rate was observed where 45% of the infected women were in the age group 26 to 30 years, 42.2% were in their 3rd trimester; also the highest infection rate (55%) was observed in third pregnancy concluding that old age pregnancy increased parity prone for UTI apart from individual hygiene and economical status.

Isolation and characterization of Pectinase producing Bacillus Subtilis from Agro Waste Dump Yards of Lahore

Hammad Arshad, Ambrin Ali, Ayesha Kanwal and Hamza Tariq

Page No: 92-97

Abstract: The findings of the faster and efficient bacterial strains for pectinases production are always of industrial importance. In present study, the isolation and characterization of pectinases producing bacterial strains from soil samples are carried out from agro waste dump yards of Lahore, Pakistan. Different soil samples were taken into sterile containers from dumpsites in Lahore. Nutrient agar medium was used for the isolation of bacteria and pectinase screening agar medium was used to identify positive bacterial isolates. Five positive isolates HAKD1, HAKD2, HAKD3, HAKV2 and HAKW2 were further subjected to morphological and biochemical studies. For further species confirmation, 16sRNA sequencing was carried out. The phylogenetic analysis was carried out using Mega7 software and on the basis of neighbor joining phylogenetic tree.

On the basis of morphological, biochemical and molecular studies, all the five strains were confirmed as Bacillus subtilis. RNA sequences were successfully submitted in National Centre for Biotechnology Information, GenBank with accession numbers KY924873, KY924874, KY924875, KY924876 and KY924877 for HAKD1, HAKD2, HAKD3, HAKV2 and HAKW2 strains respectively. The isolated bacteria were found linked with each other. Five bacterial isolates were successfully characterized and proved as the good producers of pectinases. The isolated Bacillus subtilis can produce high amount of pectinases for good number of industrial applications.

Fermentation of enzymatically saccharified rice straw hydrolysate for bioethanol production

Kaur Jaspreet, Taggar M.S. and Kocher G.S.

Page No: 98-103

Abstract:Rice straw is an attractive lignocellulosic material and sustainable resource for renewable fuel. Pre-treatment and enzymatic hydrolysis of rice straw are important for fermentable sugar production and its subsequent conversion to ethanol. In the present study, different pre-treatment processes viz. acid-steam, alkali-steam, microwave/acid, microwave/alkali and sequential acid-steam followed by microwave/alkali were compared for fractionation of cellulose, hemicellulose and lignin components of rice straw. Among different processes, sequential acid-steam followed by microwave/alkali was effective in significant removal of hemicellulose and lignin from straw.

The enzymatic hydrolysis of pre-treated rice straw by cellulases from Aspergillus niger resulted in 0.637g/g of reducing sugars during 72 h of hydrolysis with percent saccharification of 83.94%. Batch fermentation of cellulosic rice straw hydrolysate by Sacchromyces cerevisiae resulted in 1.16g/120ml ethanol with maximum ethanol yield of 0.41g/g. However, batch fermentation of hemicellulosic hydrolysate produced after acid-steam pre-treatment by co-culture of S. cerevisiae and Pachysolen tannophilus resulted in 0.48g/800ml ethanol with yield of 0.30 g/g.

Cloning, purification and kinetic characterization of L-asparaginase from Pseudomonas fluorescens

Sinha Rati and Singh Hare Ram

Page No: 104-110

Abstract:L-Asparaginase is well known enzyme for its chemotherapeutic potential since many decades. It is widely distributed in animal, plant and microbial sources. In the present study, L-asparaginase from Pseudomonas fluorescens was successfully cloned and expressed in E.coli BL21. The resulting recombinant L-asparaginase was produced and purified as confirmed by 40 kDa band on the SDS-PAGE gel. Its molecular weight was found to bo 160 kDa as revealed by native-PAGE gel. Its optimum pH was found to be 7.

The kinetic parameters such as Km, Vmax, Kcat and Kcat/Km for the recombinant L-asparaginase were found to be 4.92 mmol, 76.92 µmol/ml/min, 307.68 /min and 62.53 mmol/min respectively thereby indicating a high affinity towards its substrate L-asparagine, higher rate of reaction and kinetic efficiency. Thermostability analysis revealed half-lives at 25 ºC, 37 ºC and 45 ºC to be 43.32 h, 27.72 h and 18.73 h respectively for the recombinant enzyme. The higher half-lives of recombinant L-asparaginase enhance suitability in both chemotherapeutic and food processing applications.

Effect of Light Wavelengths on Biomass Production and Pigment Enhancement of Chlorella vulgaris in Indoor System

Bhosale Mangesh M. and Felix S.

Page No: 111-117

Abstract:Fresh water microalgae, Chlorella vulgaris, is commonly used as a food type for live feed production because of smaller size and high pigment content. The key to economic production of microalgae is to optimize lighting conditions, photoperiod and wavelength of light for efficient photosynthesis. In the investigation, C. vulgaris was grown for six days in a cylindrical FRP (Fibre Reinforced Plastic) tanks (500L) with under water light facility using acrylic pipes and LEDs (Light Emitting Diodes) at 5 klux green light (495–570 nm), red light (620–750 nm), blue light (450–495 nm) and white light (380 to 750 nm). The results showed that the highest biomass (6.50±154.21×107 cells mL-1) was observed in culture illuminated with green light at ambient temperature but having lesser cell size (2.7-5.8 µ). The biomass observed in culture illuminated with red, blue and white colour was 4.34±257.25×107 cells mL-1, 5.54±287.74×107 cells mL-1 and 5.10 ± 380.45×107 cells mL-1 respectively while cell size observed was 5.2-9.4 µ, 5.1-6.8 µ and 5.0-8.9 µ.

The highest amounts of chlorophyll a (0.141±0.17 mg mL-1) and chlorophyll b (0.177±0.13 mg mL-1) were observed in cultures illuminated with green light while the highest amount of astaxanthine (0.0126±0.35 mg mL-1) was observed in cultures illuminated with red light. To conclude, C. vulgaris can be produced in mass using green light illumination efficiently while astaxaathin content can be increased using red light illumination.

Identification of genotype specific alleles and molecular divergence evaluation among potential donors for breeding of aerobic rice

Kumari Puja, Sharma Vinay Kumar and Nilanjaya

Page No: 118-129

Abstract:Using 26 microsatellite primers, simple sequence length polymorphism was analyzed to examine the genetic divergence among 18 aerobic rice entries. Altogether 225 allelic variants including 110 shared and 115 unique alleles were detected with an average of 8.6 alleles per primer. All primers generated genotype specific alleles. However, RM 538, RM 263, RM 591, RM 3530, RM 5359 and RM 335 yielded considerably greater number of genotype specific alleles. The intermediate repeat length exhibited the highest level of polymorphism and di-nucleotide repeats with AC, CT, TC and GA repeat motifs recorded greater number of alleles in comparison to AG, AT and TG repeat motifs. Polymorphic information content varied widely (0.607 to 0.913) around the mean value (0.795), differing greatly even among the primers that generated the same number of allelic variants.

Microsatellite profiling revealed genotype specific alleles in all the entries, but their number was remarkably higher in AER-01 (IR 81429-8-31), MGD-1206, MGD-1104, IR-64, Rajendra Bhagwati, Vandana and Sahabhagi. Hierarchical classification pattern of the entries which accommodated into seven clusters exhibiting ample molecular variance even within sources of collection, was completely consistent with spatial distribution pattern along the principal coordinate axes. Highly informative markers and diverse genotypes identified in this study could be utilized in marker assisted aerobic rice breeding programs.

Biotechnological studies on bio-chemical and antioxidant properties of Bengal Currant (Carrissa carandus)

Dubey Rajesh Kumar, Babel Priyanka, Shukla Mamta and Singh R.L.

Page No: 130-134

Abstract:The present study aimed to study the biochemical and antioxidant activities in the leaf, seed, fruit, bark and twig of Carrissa carandus. The sample plant exhibited varied antioxidant and phenolic activities. Antioxidants are inhibitors of the process of oxidation even at relatively small concentration and thus have diverse physiological role. The different parts of C. carandus are dried and powdered to estimate the contents of carotenoids, vitamin C, total phenolics, protein and carbohydrate.

Results showed that the vitamin C, carotenoid (in fresh weight), total phenolic content and carbohydrate (dry weight) were significantly present in highest amount in leaf whereas ripened fruit has shown highest protein content. The results obtained from these experiments showed that the plant parts having high protein and carbohydrate content possess high total phenolic content which can be mainly responsible to scavenge the free radicals. The high ascorbic acid and carotenoids content expressed that the plant may be potential source of natural antioxidant.

Estimating the effects of Rootonic, a unique fungal preparation on Vigna radiata seeds

Kalra Charu, Das Shivangi, Kashyap Rohan, Arora Rashmi and Rana Bhavika

Page No: 135-139

Abstract:Extrapolated by its caliber to enhance plant growth, instigate stress tolerance and elicit protection, a mycorrhizal root endophyte Piriformospora indica caused the commotion in the field of agriculture. Known for its all-around association with wide range of host and benign deeds, P. indica was commercialized under the name of Rootonic. By directly manipulating the plant hormone-signaling pathway during the cause of mutualism, it achieves the versatility of colonizing a wide range of plant hosts.

The scope of this study is to evaluate the efficacy of P. indica on various parameters of growth in Vigna radiata. Discernable increase in seed germination ratio, shoot length and root length along with more profuse root branching was evident through this experimental setup. Stress combating properties of the fungal root colonization were also apparent through a/b chlorophyll ratio. However, no significant effect on leaf surface was recorded.

Recent development in molecular markers system for disease resistance in Tomato

Sajid Qurat-ul-ain and Elçi Eminur

Page No: 140-151

Abstract:Tomato (Solanum lycopersicum L.), is an important vegetable crop included in Solanaceae group and is extensively growing vegetable all over the world and a vital source of vitamins A and C. According to the data calculated in 2017 about 370168 hg/ha tomatoes were grown worldwide with the production quality of 182,305,395 million tons of tomatoes annually 1. Tomato is also considered as a dynamic ideal crop to study the biology and plant behavior, particularly ecology, biotic stress factors, fruit biology and plant-microbe interaction. Molecular markers are increasingly used for several resistance genes especially for disease resistance. Molecular markers in tomatoes have improved recognition, mapping, classification and allocation of vital characters like disease resistance etc. Due to the limited sources of cultivated tomatoes, their wild relatives take part in the development of resistance sources against disease or pathogens as well to develop new cultivars.

In this review, we are mainly discussing already detected molecular marker system those are developed for biotic resistance in tomato plants including viruses, bacteria, fungi and nematodes. The main purpose of this review is for tomato resistance genes related defense of plants against certain biotic stress factors that lead to the selection of superior plant sources for breeding of tomatoes.

Evaluation of medicinal effects of Allium cepa

Sharma Neha

Page No: 152-160

Abstract:Onion (Allium cepa) is considered to be one of the most important vegetable across the world. Contemporary science has provided insight into medicinal value of onion and its potential use in pharmacotherapy. Onion is associated with anti-cancer, anti-bacterial, anti-viral and anti-diabetic effects. Medicinal value of onion is associated with flavonoids and organosulfur compounds. The present review is an attempt to summarize research on nutritional and medicinal properties of onion.

Development of resistant variety of Capsicum annum L. against Chilli leaf curl virus (ChLCV), a major biotic stress in Chilli cultivation

Giri Alok Kumar, Jena Biswajit and Acharya Laxmikanta

Page No: 161-167

Abstract:Chilli (Capsicum annum L.) is one of the major spice crops all over the world. Among different biotic stress ChLCV is one that can ruin the crop and results in huge loss in yield. Use of pesticides proves ineffective against the virus and biotechnological approach as well as conventional breeding may be explored for the production of ChLCV. Several resistant varieties have been released by PAU, Punjab through conventional methods of plant breeding. But new strains of the virus affect the earlier variety showing resistant to old strains of ChLCV.

However molecular markers have been used for the identification of susceptible and resistant markers associated with the ChLCV. Similarly, major works were reported where mapping of these markers is described and the information can be used for the development of resistant Chilli variety. Inter specific hybridization can be useful in developing resistant variety as some species of Capsicum show resistance for the virus.

Gene trap strategies to unravel and characterize novel biotic-stress inducible genes in plants

Muthusamy Senthilkumar K., Marathe Ashish, Mahajan Mahesh, Sahu Bhimeshwari, Palaiyur N. Sivalingam, Kumar Jagdish and Kaushal Pankaj

Page No: 168-175

Abstract:Plants, being sedentary in nature constantly encounter various biotic factors such as insects, fungi, bacteria, viruses, nematodes etc. In order to combat them, plants have developed defence mechanisms at anatomical, biochemical, physiological and genetic levels. The expression of genes involved in various biological pathways including signal transduction, phytohormones signalling, osmoregulation, sugar transport, ROS homeostasis, calcium and MAPK pathways, etc., plays pivotal role in imparting resistance to biotic stresses. Therefore, identification and functional characterization of biotic-stress responsive genes are highly imperative to breed biotic stress tolerant cultivars. Gene trap strategies serve as a powerful tool to identify and unravel the biological functions of novel genes and promoters involved in stress tolerance.

The candidate gene/promoter flanking the inserted gene trap can be easily cloned using the sequence information of the trap. Various strategies of gene trapping involve T-DNA and transposon based random insertional mutagenesis, transposon based random insertional mutagenesis and activation tagging. To accomplish trapping of target sequence, various vectors have been developed. Recently, gene trap strategies have been successfully imparted to identify and characterize key genes or promoters involved in biotic stress reactions. In the present review, the various gene trap strategies used for identification and cloning of biotic stress responsive genes using DNA vector-based gene traps are discussed.