What is CRISPR Cas9 system?

CRISPR Cas9 is a system utilized by bacteria for immunity against viruses. The abbreviation can be elaborated as Clustered Regularly Inter-spaced Short Palindromic Repeats. Cas9 is an enzyme, nuclease that cuts the DNA. CRISPR Cas9 system is a system nowadays used in genetic engineering to edit genomic DNA sequences as and where desired to better understand functions of a particular gene.

Various living organisms interact with each other in nature. Viruses and bacteria do the same. A bacterium is a prokaryotic microscopic living organism consisting of a genomic DNA & a small extra chromosomal DNA ‘plasmid’. Both the genomic DNA & plasmid have ability to replicate in its own. Moreover, the bacterial cells do not exist in singles. They often form a community of bacterial cells, called biofilm.

Viruses on the other hand are microscopic infectious agents having ability to replicate at the cost of a living host cell. Host range includes all types of life forms from microorganisms such as bacteria & archaea to plants and animals.

In an interaction between bacteria and virus, viruses attack bacteria & uses the living bacterial host cell for its replication. When viruses invade bacterial cells, viral DNA is injected into bacterial cells. These DNA replicate within bacterial cells using the host machinery and form next generation of viruses. These new generation of viruses cut open the host cell through lytic or lysogenic cycle.

However, all cases of viral infection doesn’t result into same. Some bacteria can prevent itself from being infected & survive. But how ?  Here is an explanation: Continue reading

Counting fungal spores using a Hemocytometer

Hemocytometer:

A hemocytometer is a device used to count number of cells/spores present in a given sample solution (wikipedia). Invented by Louis-Charles Malassez, a hemocytometer consists of a thick glass microscope slide with a rectangular indentation that creates a chamber. Each chamber is engraved with a laser-etched grid of perpendicular lines. The area bounded by the lines and depth of the chamber is known. It is therefore possible to count the number of cells or particles in a specific volume of fluid, and thereby calculate the concentration of cells in the fluid overall. Continue reading

Huanglongbing of Citrus

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Introduction:

Huanglongbing of citrus is one of the most destructive disease of citrus fruits worldwide.  Known with different names in different regions of the world, they cause a huge economic loss on part of citrus producers of the world. “Yellow shoot disease” in China, “likubin” (citrus decline) in Taiwan, “dieback” in India, “leaf mottle yellow” in the Philippines, “vein phloem degeneration” in Indonesia and “yellow branch”, “blotchy-mottle” or “citrus greening” in South Africa are the commonly referred names of Huanglongbing (HLB) of citrus. This devastating disease has been known to be caused by a gram negative bacterium “Candidatus Liberibacter” and vectored by psyllids. Continue reading

Fungicide Sensitivity Assay – screening resistance of a pathogen against a fungicide

A plant that is able to maintain its normal physiological and biochemical functions can be termed as healthy. When its normal functions are interrupted through a continuous irritation by any biotic or abiotic factors, the plant suffers, either pathological or physiological (non-pathological) disorder.

Fungus is one of the biotic factors causing economically important plant diseases such as late blight of potato (Phytophthora infestans), apple scab (Venturia inequalis), powdery mildew, downey mildew etc. Various plant management strategies are employed to take care of such diseases such as crop rotation, nutrient management, irrigation management, tillage etc. Management of plant diseases through the use of chemical pesticides is also common. The pesticides are meant to be applied at a specific rate and method. In an attempt to achieve complete control of the pest, farmers have been seen to apply the pesticides at greater rate than recommended which may control the disease to a greater extent for time being but helps to develop resistance in the pathogens.

Several fungicides have been developed to manage fungal diseases in plant. Fungicides either kill the fungal pathogens or prevent them from causing disease on the plants. Application of fungicides with a single site mode of action can be overcome by fungal pathogens over time  They need to be updated at a regular interval for efficacy because they fail to manage the disease over time. Fungal pathogens evolve with time and overcome the effect caused by the fungicides and are rendered insensitive/tolerant or resistant to the fungicide.

Several lab based experiments are performed to determine whether a fungal pathogen is sensitive or has developed resistance against a fungicide. These lab based experiments are helpful in making successful recommendations for using a fungicide.

Here I present a lab based Fungicide Sensitivity Assay Protocol which can be used to judge whether or not a fungus is resistant to a fungicide used against it. Explained below is the experiment I conducted for assaying the sensitivity of two fungicides: Tebuconazole and Metconazole to the fungus Fusarium graminearum causing Fusarium Head Blight in cereals. Continue reading

Beneficial Insects of Our Farm: An Overview

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What Do Ladybugs Eat?

Lady beetle larvae and adults eat aphids, small caterpillars, mites and random insect eggs. A few species specialize by feeding on scale insects, mealybugs, mites and even powdery mildew. Adult lady beetles also eat insect honeydew, flower nectar and pollen.

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How to Attract Ladybugs ?

Tolerate light aphid outbreaks in spring, because they are an important food source for lady beetles, which emerge earlier in the season compared with hoverflies or lacewings. Do Continue reading

Climate Smart Agriculture

Climate Smart Agriculture- Helping the People produce more food

Climate Smart Agriculture- A Triple Win

Climate smart agriculture source book

About Climate-smart agriculture:

Achieving food security and responding to the challenges of climate change are two goals that must be achieved together. That’s why agriculture, fisheries and forestry in developing countries must undergo a significant transformation.

As population is on the rise food consumption patterns are destined to follow the same upward trend. Food production will need to increase by at least 60% to meet the demands of this growing population by 2050. Studies show that climate change is likely to reduce food productivity, its production stability and incomes in some areas that already have high levels of food insecurity.

Climate-smart agriculture promotes production systems that sustainably increase productivity, resilience (adaptation), reduces/removes Green House Gases (GHGs) (mitigation), and enhances achievement of national food security and development goals.

The recognition for the importance of adopting climate smart practices, policy and finance in the international arena has been growing. A number of countries lead by the Netherlands organized the Hague conference on Agriculture, Food security and Climate change in November 2010. Technical guidance and support was provided by FAO and the World Bank. The conference led to the development of a roadmap of action. (see: http://www.afcconference.com/the-first-conference/135-final-roadmap-for-action)

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THE HAGUE CONFERENCE ON AGRICULTURE, FOOD SECURITY AND CLIMATE CHANGE Continue reading

Farmers’ Field School Approach

1. History, Origin and Emergence:

The Farmers’ Field School (FFS) approach emerged out of a concrete, immediate problem. At the end of the 80’s of the last century farmers in Indonesia were putting their crops, their health and their environment at severe risk through massive abuse of highly toxic pesticides promoted aggressively by the private industry and government. Pest species were becoming resistant and in some cases resurgent. What was called for was a large-scale decentralized program of education for farmers wherein they become “experts” in managing the ecology of their fields – bringing better yields, fewer problems, increased profits and less risk to their health and environment (Dilts, 2001). Continue reading

Organic Production- An Interesting Business

 

Organic vegetable Production site at Dhading District

Organic vegetable Production site at Dhading District

Why is Organic Production an interesting business?

  • Consumers have an interest in organic production mainly for environmental and health reasons. They are increasingly concerned about the social and ecological production conditions of the products they buy.
  • Development agencies support it because they see it as a way to reduce poverty.
  • Business People may be attracted to the organic sector because they hear that there is a growing market that offers premium prices and therefore higher margins.
  • Some think that the products they deal with are already organic and just need to be certified, so it would be an easy way to make more profit.
  • Others are involved because they have sympathetic feeling with the goals of Organic Farming; with helping farmers, and doing something good for the environment.
  • Some like the exclusivity of it; they like the image, they like to stand out from crowd, and to be a part of the People-Planet-Profit Market.

Continue reading