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Category: Agriculture

Genetically “curing” an infertile crop plant into fertile again

Plant geneticists from the University of Tokyo are onto creating novel plant lines that seem to be “more polite” than they already are.1,2,3 However, their technique does not involve implanting a “social” gene of some sort. Rather, scientists would edit plant mitochondrial DNA. In that way, they can, for instance, make a plant bow down even more due to the heavier seeds it would yield. Thus, this could mean a more secured food supply. More interestingly, this genetic modification was accordingly the first time ever to be done on a plant mitochondrial DNA.

Mitochondrial DNA

Mitochondria are one of the three organelles containing nuclear material. The nucleus and the chloroplast are the other two. Scientists have already done successful modifications of the nuclear DNA since1970s. Then, another team of researchers pioneered modification of chloroplast DNA in 1988. However, in terms of mitochondrial DNA, researchers had only found success on animals but not on plants. The first successful animal mitochondrial DNA modification happened in 2008. Then recently, a team of researchers from the University of Tokyo apparently showed success in doing it as well on a plant mitochondrial DNA. In this case, this was the first time.

Basically, mitochondrial DNA is the genetic material in the mitochondrion that carries code for the manufacturing of RNAs and proteins essential to the various functions of the said organelle. Since a mitochondrion has its own genetic material it is described as a semi-autonomous, self-reproducing organelle.

First plant mitochondrial DNA modification

Researchers from the University of Tokyo devised genetic tools that can edit plant mitochondrial DNA. Accordingly, they came up with four new lines of rice and three new lines of rapeseed (canola) using their technique. Between plant and animal mitochondrial genes, those in plants are larger and more complex. Prof. Arimura explicated that plant mitochondrial genes are more complicated in a way that some mitochondria have duplicated genes whereas others lack them. Thus, manipulating plant mitochondrial genome proved more challenging. Their collaboration with other researchers, particularly from Tohoku University and Tamagawa University, led them to their use of the technique mitoTALENs. With it, they were able to manipulate mitochondrial genes in plants.1 To learn their methods in detail you may read their published work here.


The plant mitochondria rapidly moving around the cell (Arabidopsis leaf epidermal cell). Artificially made to glow green to show their actual speed. Video by Shin-ichi Arimura CC-BY

What plant mitochondrial DNA modification can do

After the successful editing of plant mitochondrial DNA, what could be the next big thing? Associate Professor Shin-ichi Arimura, leader of the research team, was enthusiastic indeed about their accomplishment. With a jest, he said, “We knew we were successful when we saw that the rice plant was more polite — it had a deep bow” – implying that a fertile rice plant would bend more due to the heavier weight of the seeds it would yield.1,3

A weak genetic diversity in crops could impose a threat to species survival through time. As a domino effect, that is bad news to our food supply.  Thus, their team hope to use their technique by providing solutions that could significantly enhance genetic diversity in crops, and therefore improve plant species survival and yield. Arimura further said, “We still have a big risk now because there are so few plant mitochondrial genomes used in the world.”1 Furthermore, he mentioned of using their technique for the purpose of adding the much needed mitochondrial DNA diversity among plants.

Cytoplasmic male sterility

plant mitochondrial DNA modification technique
Plant mitochondrial DNA modification technique to enhance crop yield and genetic diversity

Cytoplasmic male sterility (CMS) refers to the male sterility in plants by not producing functional pollen, anthers, or male gametes. It occurs naturally although rarely and probably involve certain nuclear and mitochondrial interactions.4 Nonetheless, others believe that CMS is caused primarily by plant mitochondrial genes.1  In particular, the presence of CMS gene leads to this condition in plants. Thus, removing the CMS gene could convert the plant into becoming fertile again. This is just a start but they are already optimistic that with their technique they could improve crop lines and consequently secure food supply.

plant mitochondrial DNA modification
A mitochondrial gene that causes cytoplasmic male infertility was deleted using a mitoTALENs technique. Infertile rice (right) stands straight, but fertile rice (left) bends under the weight of heavy seeds. Image by Tomohiko Kazama, CC-BY

— written by Maria Victoria Gonzaga

References:

1 University of Tokyo. (2019, July 8). Researchers can finally modify plant mitochondrial DNA: Tool could ensure genetic diversity of crops. ScienceDaily. Retrieved from [Link]

2 Arimura, S. -i., Yamamoto, J., Aida, G. P., Nakazono, M., & Tsutsumi, N. (2004). Frequent fusion and fission of plant mitochondria with unequal nucleoid distribution. Proceedings of the National Academy of Sciences101(20), 7805–7808. [Link]

3 Researchers can finally modify plant mitochondrial DNA | The University of Tokyo. (2019). Retrieved from The University of Tokyo website: [Link]

4 Campo, C. (1999). Biology of Brassica coenospecies. Amsterdam New York: Elsevier. pp.186-89.

Antibiotics removal by walnut shell based activated carbon

Antibiotics are the most common compounds that are found in groundwater, surface water, drinking water and wastewater. Also, traces of these antibiotics found in sewage sludge, soil and sediments that caused concern to the environment. Besides, the emergence of antimicrobial resistance becomes the major health problem worldwide. Nonetheless, therapeutic used of antimicrobials in human and veterinary medicine contributes to the widespread of resistant microorganisms. On the other hand walnut shells are among the waste materials that have been suggested to have efficient sorbent alternatives. Due to its low ash content and been used as low cost sorbent for metal and oil removal.

Walnut shell activated carbon in removal of antibiotic

Advance treatment of wastewater confirming the positive results in lowering the presence of antibiotic residues. These include ozonation, membrane separation, advanced oxidation, reverse osmosis and nanofiltration. In which, the vast applicability of activated carbon in pollutants removal are always dependent on the conditions of raw materials. So, this particular research, the walnut shell has been used since it is a precursor material for activated carbon production. Moreover, the activated carbons ability to remove organic micro-pollutants lies on the solution and contaminants properties. Apparently, the absorption of antibiotic Metronidazole shows the conditions that maximize expected results.

 

The influence of temperature on the absorption capacity of  antibiotic is slightly significant. As a result, the absorption capacity depends on the nature of the activated carbon and its chemical characteristics, morphology and solutes. Also, the nature of solutes affecting electronic density influences the interactions with the matrix of the absorbent. In addition, activated carbon is the most common process to remove dissolved organic and inorganic compounds. Its great flexibility in applications arises from physical and chemical properties on specifically treated carbon materials.

 

As a result, the absorption amount of organic compounds depends strongly on essential properties of the absorbent. However, it can be slightly affected by some variables like temperature, pH, ionic strength and contact time. Therefore, antibiotic shows positive effect on the interaction of the absorbed amount. So, activated carbon from walnut shell might represent a good agent in removing antibiotic residues.

 

Sources: Prepared by Joan Tura from ScienceDirect: Science of the Total Environment

Volume 646, 1 January 2019 Pages 168-176

Ecosystem carbon emissions from forest fires in Alaska

Carbon emissions in Alaska relied on measurements of trees and changes in surface organic layer carbon pools after large-scale burning. In 2015 hundreds of forest fires burned across the state of Alaska resulted as second highest acreage burned in a year.  Nearly 300 forest fires occur in a week, as a result over 61,000 lightning strikes detected during this period. As of mid-September a total of 2.1 million hectares has been burned statewide in 700 separate forest fires. Deeper burning of surface layers happened during fires and on more well-drained sites at moderate to high severity levels. Summer of 2015 in Alaska has an exceptionally warm and dry condition following the largest forest fires recorded in decade.

 

Forest fires estimated carbon emission

Estimated burned depth from forest fires consumed almost the surface organic moss layers at about 5cm-10cm depth. This estimate confirmed using the relationship of every centimeter of organic mat thickness and soil temperature under organic layer. In sternly burned forest a total consumption of living moss organic layer is directly associated with warming at the soil surface layer. Additionally, soil temperature at about 30cm depth has 8–10 °C higher compared to unburned forest sites. Therefore, forest fire impacts on forested areas caused a fivefold decrease in surface organic layer thickness. As well as doubling of water storage in the soil layer, doubling in thaw depth and increase soil temperature.

 

Moreover, carbon emissions include the measurement above ground biomass and changes in surface organic layer carbon pools. In 2017 field surveys of Tanana, Alaska shows no live surface organic layers remained from 2015 forest fires. Due to these intense fires only residual dead, charred moss and lichen left behind that could not insulate soil layers. Also, post-fire thickness of organic layer and thermal conductivity are important factors to determine soil temperature and thaw depth. Nevertheless, the role of mineral to the total ecosystem carbon emissions is higher in forests that are normally calculated.

 

Forest fires have overall percentage of more than 60% in interior Alaska. And this abrupt removal of moss and soil organic layer elevates post-fire soil temperatures and thaw depths. Because of this a massive loss of carbon and nitrogen from soil layer minerals. As well as, a much warmer and wetter surface layer compared to unburned forest nearby. Therefore, carbon emissions are due to the addition of mass wasting of soil mineral in 2 years following forest fires.

 

Source: Prepared by Joan Tura from  BMC Carbon Balance and Management

Volume 13:2 January 8, 2018

Role of selenium-fortified yogurt against aflatoxin-contaminated nuts

Aflatoxins produced by a certain molds that are poisonous carcinogens which grow mostly in soil, hay, decaying plants and grains. It can affect livestock and human as natural contaminants in foods like peanuts and corn meal. There are four types of aflatoxins these are B1, B2, G1 and G2 in which all are teratogenic, carcinogenic and immunosuppressive. Its toxic effect might be due to the generation of free radicals resulting into lipid peroxidation that damage biological system. On the other hand yogurt is produced from the bacterial fermentation of milk. In which bacteria produces lactic acid that acts on milk protein to give yogurt its texture and tart flavor. However, yogurt contains plenty of probiotic bacteria that offer benefits as microflora in the intestines. It also helps boost immune response and suppress carcinogenesis since fermented dairy products contain live lactic acid bacteria.

 

Selenium-fortified yogurt protects against aflatoxin toxicity

Yogurt has been known as therapeutic to various disorders including lactose intolerance, indigestion, intoxication, gastroenteritis, kidney, liver disorders and cancer. Selenium added to yogurt considered as the basic trace elements vital for normal growth and development in humans and animals. It also acts as anti-oxidant as well as improves nutritional values. Additionally, selenium has both enzymatic and structural functions that protect harmful reactive oxygen and minimized the production of hydrogen peroxide from aflatoxins. Ingestion of aflatoxins leads to weight loss due to the change in digestive enzymes activity that causes malabsorption of nutrients.

 

Aflatoxins will impair the biosynthesis of protein which results to the degranulation of the endoplasmic reticulum. It also caused liver fibrosis and poses health risk to humans and livestock. In this research , a positive results shows that selenium-fortified yogurt suppress the level of aflatoxins in rats. It also proved that with selenium contents inhibit the activity of enzymes related to carcinogenesis. Since yogurt improves intestinal mucosa and microflora that influence intestinal barrier. These yogurt bacteria inhibit the peroxidation of lipids by foraging reactive oxygen.

 

Therefore, consumption of nuts infected with aflatoxins caused toxicity mainly at the kidney and liver. But intake of selenium-fortified yogurt can definitely suppress against aflatoxins toxicity. In general, application of probiotic bacteria and selenium is vital and viable therapeutic approach to improve safety in food industry. Indeed, it is recommended to eat fresh nuts to avoid aflatoxins along with selenium-fortified yogurt to lessen its toxicity.

 

Source: Prepared by Joan Tura from BMC Agriculture and Food Security

Volume 7:21, June 2018

 

 

Why do Farmers Abandon Jatropha Cultivation? Case from Mexico

Jatropha belongs to the flowering plants that have been known for biodiesel production. It has been intensively promoted for renewable energy source in tropical areas worldwide. For the last decades many projects of jatropha has been implemented in Africa, Asia and Latin America. In which most of its purpose is to reduce energy dependency, sustainable development and greenhouse gases emissions. Oil from this plant is converted into biodiesel and used for diesel engines. Also, its protein-rich product used for fish and animal feeds as well as on high quality organic fertilizers. Recently, profitability and viability of jatropha declined and unexpected low yield as well as lower price for the seed. But labor and maintenance costs of the fields still the same that is why cultivation of jatropha slows down. The aim of this research is to assess different factors affecting farmers on jatropha cultivation in Chiapas Mexico.

 

Production of Jatropha in Chiapas Mexico

Plenty of small farmers cultivate jatropha to improved livelihood productions. Yet, in recent years many of them discontinue planting due to some reasons. Such as, socio-economic, environmental and institutional factors motivating decisions of the farmers to discontinue the production. The Chiapas Government provides subsidy to the farmers including seeds and seedlings as well as technical assistance for the maintenance. Between 2007-2011 52% in Chiapas Mexico planted jatropha yet, about a year after abandonment of plantations is rampant among farmers.

 

As a results farmers perceived that cultivation of jatropha will not offer good economic benefits. Because it is just a waste of time, costs of labor, energy, land and financial resources. However, wealthy farmers adopt the cultivation and have access to develop new technologies. But those who received subsidy from the Government are relatively poorer which tend to abandon the cultivation. The occurrence also of pest and diseases is the other factors that motivate farmers to abandon the cultivation.

 

In addition, incentive payment, lack of profitability of the crop, commercialization and wealth status are important factors that makes the farmers decide to abandon jatropha cultivation. Therefore, this research may be helpful for future implementation of bioenergy. Not only in Mexico but to several places worldwide where similar programmes of jatropha production have been implemented. It is very important to evaluate the trade-offs between cost and gains of the farmers. Particularly the accurate calculation of cost benefits analyses that a farmer can make. So that it would prevent abandonment of plantation and to ensure continuity  of the farmers.

 

Source: Prepared by Joan Tura from Energy for Sustainable Development

Volume 42, February 2018, Pages 77-86