Use of Crispr/Cas9 for Development of Disease Resistant Cultivars in Plant Breeding

Crop protection against pests and diseases is a major challenge in agriculture. Plant breeding is a key solution for the development of disease resistant cultivars. Gene editing is an indispensable part of plant breeding to obtain desirable traits in crops. CRISPR (Clustered Regular Interspaced Palindromic Repeats)/Cas9 (CRISPR- associated protein) is a recent breakthrough in gene editing technology. It can be utilized to exploit defensive mechanism in plants against pathogen attack with recognition and degradation of the invading pathogenic genes by bacterial immune system. Advances in plant breeding with integration of CRISPR/Cas9 have facilitated the production of cultivars with heritable resistance to viral and bacterial disease. CRISPR/Cas9 mediated genetically engineered resistance can be inherited to further generation of crops after segregation of Cas9/sgRNA transgene in F1 generation. The segregation of Cas9/sgRNA transgene prevents undesirable genome modification in successive generation and makes use of CRISPR/Cas9 safe in plant breeding. CRISPR/Cas9 proves itself as a fascinating tool to revolutionize plant breeding for the development of various disease resistant cultivars however, effects of CRISPR/Cas9 system on different physiological process of plants still needs to be studied.Int. J. Appl. Sci. Biotechnol. Vol 5(4): 403-40

use of predators for the biological control of eriosoma lanigerum wooly apple aphids on apple

Due to increase demand of organic products, biological control methods have gained interest all over the world. Eriosoma lanigerum, commonly known as Wooly apple aphid, is a serious pest of apple. The negative impacts of pesticides on environment and human life make Biological control an important model in the control of the Wooly apple aphid. Some of the biological control agents that have been used in the control of this pest are predators, parasitoids, nectar of flowers etc. The role of the parasitoid Aphelinus mali in the biological control of wooly aphid has been studied by many researchers and found that use of parasitoids Aphelinus mali is not effective when they attack WAA solely in apple orchards. However, efficiency of use of Aphelinus mali in control of WAA is higher when these parasitoids are used along with natural predators (Gontijo, 2011).In recent days, there has been increasing use of predators for the control of aphids. This review focuses on some of the mostly used predators like syrphids, lacewings, earwigs etc. and their role in WAA management. This review focuses on the feeding habits of predators used as biocontrol agents against WAA as well as the occurrence time of these predators before their integration in management practices. Also; this review provides insight into the integration of predators along with other natural enemies for productive control of WAA. This review can be source of information for producers, as well as researchers who are focusing on organic production of apples and integrated wooly aphid management.Int. J. Appl. Sci. Biotechnol. Vol 5(4): 410-41

Analysis of Chlorophyll Content and Its Correlation with Yield Attributing Traits on Early Varieties of Maize (Zea Mays L.)

Chlorophyll has direct roles on photosynthesis and hence closely relates to capacity for photosynthesis, development and yield of crops. With object to explore the roles of chlorophyll content and its relation with other yield attributing traits a field research was conducted using fourteen early genotypes of maize in RCBD design with three replications. Observations were made for Soil Plant Analysis Development (SPAD) reading, ear weight, number of kernel row/ear, number of kernel/row, five hundred kernel weight and grain yield/hectare and these traits were analyzed using Analysis of Variance (ANOVA) and correlation coefficient analysis. SPAD reading showed a non-significant variation among the genotypes while it revealed significant correlation with no. of kernel/row, grain yield/hectare and highly significant correlation with no. of kernel row/ear and ear weight which are the most yield determinative traits. For the trait grain yield/ha followed by number of kernel row/ear genotype ARUN-1EV has been found comparatively superior to ARUN-2 (standard check). Grain Yield/hectare was highly heritable (>0.6) while no. of kernel / row, SPAD reading, ear weight, number of kernel row/ear were moderately heritable (0.3-0.6). Correlation analysis and ANOVA revealed ARUN-1EV, comparatively superior to ARUN-2 (standard check), had higher SPAD reading than mean SPAD reading with significant correlation with no. of kernel/row, no. of kernel row/ear, ear weight and grain yield/ha which are all yield determinative traits . This showed positive and significant effect of chlorophyll content in grain yield of the maize.Journal of Maize Research and Development (2015) 1(1):134-145DOI: http://dx.doi.org/10.5281/zenodo.3426

Transformation systems, gene silencing and gene editing technologies in oomycetes

Oomycetes are spore-forming eukaryotic microbes responsible for infections in animal and plant species worldwide, posing a threat to natural ecosystems, biodiversity and food security. Genomics and transcriptomics approaches, together with host interaction studies, give promising results towards better understanding of the infection mechanisms in oomycetes and their general biology. Significant development and progress in oomycetes genomic studies have been achieved over the past decades but further understanding of molecular processes, gene regulations and infection mechanisms are still needed. The use of molecular tools such as CRISPR/Cas and RNAi helped elucidate some of the molecular processes involved in host invasion and infection both in plant and animal pathogenic oomycetes. These methods provide an opportunity for accurate and detailed functional analysis involving various fields of studies such as genomics, epigenomics, proteomics, and interactomics. Functional gene characterisation is essential for filling the knowledge gaps in dynamic biological processes. However, every method has both advantages and limitations that should be considered before choosing the best method for investigating a particular research question. Here we review transformation systems, gene silencing and gene editing techniques in oomycetes, how they function, in which species and what are their main advantages and disadvantages

Analysis of chlorophyll content and its correlation with yield attributing traits on early varieties of maize (Zea mays L.)

ABSTRACT Chlorophyll has direct roles on photosynthesis and hence closely relates to capacity for photosynthesis, development and yield of crops. With object to explore the roles of chlorophyll content and its relation with other yield attributing traits a field research was conducted using fourteen early genotypes of maize in RCBD design with three replications. Observations were made for Soil Plant Analysis Development (SPAD) reading, ear weight, number of kernel row/ear, number of kernel/row, five hundred kernel weight and grain yield/hectare and these traits were analyzed using Analysis of Variance (ANOVA) and correlation coefficient analysis. SPAD reading showed a non-significant variation among the genotypes while it revealed significant correlation with no. of kernel/row, grain yield/hectare and highly significant correlation with no. of kernel row/ear and ear weight which are the most yield determinative traits. For the trait grain yield/ha followed by number of kernel row/ear genotype ARUN-1EV has been found comparatively superior to ARUN-2 (standard check). Grain Yield/hectare was highly heritable (>0.6) while no. of kernel / row, SPAD reading, ear weight, number of kernel row/ear were moderately heritable (0.3-0.6). Correlation analysis and ANOVA revealed ARUN-1EV, comparatively superior to ARUN-2(standard check), had higher SPAD reading than mean SPAD reading with significant correlation with no. of kernel/row, no. of kernel row/ear, ear weight and grain yield/ha which are all yield determinative traits . This showed positive and significant effect of chlorophyll content in grain yield of the maize

Bacteriological Profile of Surgical Site Infection Following Gastrointestinal Surgery and Their Antibiogram

Background: Surgical site infection is one of the common complication following abdominal surgery. It causes great morbidity and mortality, further increasing prevalence of multidrug resistant bacteria have made its management very challenging. The current study aims to identify causative agent responsible for surgical site infection and their antibiotic resistance patterns. Methods: This study was conducted among patients developing surgical site infection following gastrointestinal surgery in Tribhuvan university teaching hospital over a period of one year. The samples were collected and processed according to standard methods. The bacterial pathogens with their antimicrobial susceptibility were determined and resistant pattern like methicillin resistant Staphylococcus aureus and extended spectrum beta lactamase were further detected. Results: A total of 832 patients had under gone gastrointestinal surgery during the study period. Among them, 162 cases (19.5%) developed surgical site infection and 125 cases showed growth in culture. A total of 160 aerobic bacteria were isolated; Escherichia coli (29.9%) was the commonest organism with 40.8% being extended spectrum beta lactamase producer and 47.4% of Staphylococcus aureus were methicillin resistant. About 75.9% (85/112) of gram negative bacteria and 60.4% (29/48) gram positive bacteria were multi drug resistant. Conclusions: The burden of multi drug resistant bacteria causing surgical site infection is high which needs to be addressed timely. Good surveillance of bacterial antibiogram and rational antimicrobial use is necessary to reduce emergence and spread of resistant bacteria. Keywords: Extended Spectrum beta lactamase; gastrointestinal surgery; methicillin resistant staphylococcus aureus; multi drug resistance; surgical site infectio

Transformation systems, gene silencing and gene editing technologies in oomycetes

Oomycetes are spore-forming eukaryotic microbes responsible for infections in animal and plant species worldwide, posing a threat to natural ecosystems, biodiversity and food security. Genomics and transcriptomics approaches, together with host interaction studies, give promising results towards better understanding of the infection mechanisms in oomycetes and their general biology. Significant development and progress in oomycetes genomic studies have been achieved over the past decades but further understanding of molecular processes, gene regulations and infection mechanisms are still needed. The use of molecular tools such as CRISPR/Cas and RNAi helped elucidate some of the molecular processes involved in host invasion and infection both in plant and animal pathogenic oomycetes. These methods provide an opportunity for accurate and detailed functional analysis involving various fields of studies such as genomics, epigenomics, proteomics, and interactomics. Functional gene characterisation is essential for filling the knowledge gaps in dynamic biological processes. However, every method has both advantages and limitations that should be considered before choosing the best method for investigating a particular research question. Here we review transformation systems, gene silencing and gene editing techniques in oomycetes, how they function, in which species and what are their main advantages and disadvantages