CROP BIOTECH UPDATE
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A weekly summary of world developments in agri-biotech for developing countries, produced by the Global Knowledge Center on Crop Biotechnology, International Service for the Acquisition of Agri-biotech Applications SEAsiaCenter (ISAAA)
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December 13, 2017
In This Week’s Issue:
News
Global
• FAO Calls for Urgent Actions to Reverse the Rise in Hunger
• Global Impact of Not Planting Herbicide Tolerant Crops Due to Glyphosate Ban
Americas
• Study Identifies Genetic Basis of Western Corn Rootworm Resistance
• New Technique to Help Plant Breeders Develop Drought Resistant Varieties Faster
Asia and the Pacific
• Australian OGTR Invites Comments for Field Trial of GM Perennial Ryegrass
Europe
• Max Planck Researchers Engineer Key Enzyme in Photosynthesis
Research
• DND1-Silencing in Potato and Tomato Confers Resistance to Botrytis cinerea
• ThPP1 Gene Enhances Alkali Stress Tolerance in Transgenic Rice
• Arabidopsis' AtGOLS1 Gene Negatively Regulates Seed Germination
New Breeding Technologies
• Indian Researchers Test CRISPR-Cas9 Genome Editing in Banana
• Lignin Reduction Observed in CRISPR-Edited Switchgrass
Beyond Crop Biotech
• Salk Scientists Use Modified CRISPR System to Treat Diseases
Document Reminders
• Sugarcane in Africa
• Biotech Crop and Traits Annual Updates
• ISAAA Blog: Clive James and ISAAA, Top Sources of Info on Biotech in the Philippines
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NEWS
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Global
FAO CALLS FOR URGENT ACTIONS TO REVERSE THE RISE IN HUNGER
With the recent increase in the number of hungry people globally, urgent actions are needed to overturn this condition, according to Jose Graziano da Silva, Director-General of the Food and Agriculture Organization of the United Nations (FAO). He mentioned this during a meeting with the FAO Council on December 4, 2017 in Rome, Italy.
He stressed that the latest hunger figure of 815 million people is the first increase after over ten years of steady decrease. Furthermore, obesity and overweight statistics are also growing, in developed and developing countries, which is another area of concern in the current food systems.
"The most important thing to do now is to build the resilience of poor people to face the impacts of conflicts and climate change," making sure that humanitarian assistance is combined with development actions to chart a course towards the eradication of hunger by 2030, he said.
"This basically means new investments - I would say much more investments - from the public but also the private sector," Graziano da Silva said.
Read the news release from FAO.
What will happen if herbicide tolerant crops are no longer available because glyphosate is banned? This questioned was answered by PG Economic's Graham Brookes, and Purdue University's Farzad Taheripour and Wallace Tyner in their research article published in GM Crops and Food.
According to the paper, the initial impacts include loss of global farm income amounting to US$6.76 billion, and decrease in the production of soybean, corn, and canola, by around 18.6 million tons, 3.1 million tons and1.44 million tons, respectively. The environment would be directly affected as well, due to increase in the use of other herbicides with 8.2 million kg of active ingredient, and larger net negative environmental impact quotient of 12.4%. Furthermore, there will be an increase in carbon emissions due to fuel usage and reduced soil carbon sequestration, as if adding 11.77 million cars more on the roads.
Other effects on global welfare were also predicted using Computable General Equilibrium (CGE) model GTAP-BIO and found that most impacts are negative. World prices of all grains, oilseeds, and sugars are expected to rise. Land use area for crops is also expected to increase by 762,000 ha, which may further lead to deforestation, and increase in more carbon dioxide emissions.
Read more from the open-access article in GM Crops and Food.
A new study by University of Illinois researchers has uncovered the genetic basis of resistance to western corn rootworm. The study was conducted within the context of a large, long standing project called Germplasm Enhancement of Maize (GEM), which aims to diversify the tools available to corn breeders by tapping the genetic resources of maize accessions from all over the world.
The researchers did not find the gene for resistance, but they identified regions of the genome that appear to contribute to resistance, using QTL mapping. Looking at the genes in those regions, they found that ascorbate biosynthesis is common. One mechanism explaining western corn rootworm resistance might be the manufacture of ascorbate in plants. The ascorbate synthesis pathway produces free radicals that injure feeding insects.
Their analysis turned up another set of genes that may be involved in resistance, although a little more complex. When western corn rootworm larvae are feeding on roots, some corn plants release a compound into the soil that calls nematodes to attack the larvae. The second set of genes appears to be related to the manufacture of compounds that attract those nematodes.
For more details about this research, read the University of Illinois College of ACES News.
Scientists from the Canadian Light Source (CLS) have teamed up with researchers from the University of Saskatchewan (U of S) to develop a new technique to examine drought tolerance in wheat. Led by Chithra Karunakaran and Karen Tanino, the team developed a simple non-destructive method to screen hundreds of wheat leaf samples in a day, reducing the time and cost associated with traditional breeding programs to select varieties for drought tolerance.
Using the wax of a flag leaf as their test subject, the research team examined the morphological characteristics of the plant, as well as the chemical signatures, comparing the drought-resistant Stettler wheat variety to the Superb, which is more vulnerable to drought conditions.
With the help of the bright light produced at the CLS, Karunakaran and her team were the first to link micro and macronutrients in the leaves for their ability to tolerate drought, finding higher levels of zinc in the drought-resistant Stettler. These results have significant implications for future breeding programs, and also raise questions about the role of zinc in fertilizer.
For more details, read the CLS News.
The Australian Office of the Gene Technology Regulator (OGTR) is currently assessing license application DIR 160 from the Department of Economic Development, Jobs, Transport and Resources in Victoria, for a field trial (limited and controlled release) of perennial ryegrass genetically modified (GM) for fructan biosynthesis.
The field trial will assess the agronomic characteristics of the GM perennial ryegrass plants under field conditions and to multiply seed for future trials. The field trial is proposed to be conducted between May 2018 and June 2020 in southwest Victoria on a maximum area of 160 m2 per year. The GM perennial ryegrass grown in this field trial would not be used in human food or animal feed.
The Gene Regulator has prepared the Risk Assessment and Risk Management Plan (RARMP) for the application which concludes that the proposed release would pose negligible risk to human health and safety or to the environment. The Regulator welcomes written submissions to finalize the RARMP, which will then inform the decision on whether or not to issue the license. Submissions should be received by close of business on January 18, 2018.
For more details, read the DIR 160 documents available at the OGTR website.
Researchers at the Max Planck Institute of Biochemistry have succeeded in producing functional plant Rubisco in a bacterium, allowing genetic engineering of the enzyme. Rubisco, a critical enzyme in photosynthesis, catalyzes the first step in carbohydrate production in plants, the fixation of CO2 from the atmosphere.
The researchers, led by Dr. Manajit Hayer-Hartl, generated functional plant Rubisco in a bacterial host by simultaneously expressing plant chaperones and Rubisco in the same cells. This enabled the scientists to understand the complex assembly pathway of Rubisco, and also modify the Rubisco gene to improve its properties. Once they have obtained a Rubisco variant with a desired trait, they can insert the modified gene back into the plant cells, a key-step towards improving photosynthesis through Rubisco engineering.
"The bacterial expression system resembles an assembly line for cars. Whereas previously, every optimized variant of Rubisco had to be painstakingly expressed in a transgenic plant, which takes a year or more to generate - like building a car by hand - we can now make hundreds or thousands of Rubisco variants in days or weeks. It is like building cars in an automated assembly line," explains Dr. Hayer-Hartl.
For more details, read the Max Planck Institute of Biochemistry news release.
Botrytis cinerea infects many crops including potato and tomato. Major genes for complete resistance to B. cinerea are not known, but a few quantitative trait loci (QTL) have been described in tomato. Previous studies have also proven that the loss of function of particular susceptibility (S) genes may provide resistance to B. cinerea in Arabidopsis.
Kaile Sun Wageningen University & Research used RNAi to silence the orthologs of Arabidopsis S genes DND1, DMR6, DMR1 and PMR4 in potato and the DND1 ortholog in tomato. The DND1-silenced potato and tomato plants showed significantly reduced B. cinerea leaf lesions as compared to control plants. Reduced lesions were also observed on the leaves of DMR6-silenced potato plants but only at 3 days after inoculation.
On the other hand, the DMR1 and PMR4-silenced potato transformants were still susceptible to B. cinerea as the control plants. Microscopic analysis in DND1-silenced potato and tomato leaves revealed that a significantly lower number of B. cinerea conidia remained attached to the leaf surface of the DND1-silenced potato and tomato plants. Moreover, the growth of the hyphae was also hindered.
Silencing of DND1 led to reduced susceptibility to Botrytis, which was found to be related to the impediment of conidial germination and attachment as well as hyphae growth. These provide new insights regarding the use of S genes in resistance breeding.
For more on this study, read the article in BMC Plant Biology.
Inorganic pyrophosphorylase is essential in the hydrolysis of pyrophosphate to inorganic phosphate during plant growth. Chinese scientists led by Rui He of Shenyang Agricultural University and the Chinese Academy of Agricultural Sciences, studied the transgenic rice overexpressing a soluble inorganic pyrophosphatase gene, ThPP1, from salt cress (Thellungiella halophila) in response to alkaline stress (AS).
Analysis showed that the transgenic lines revealed an enhanced tolerance to AS compared to the wild type. A total of 379 differentially-expressed genes were also found to be upregulated in the leaves of the transgenic lines. Further analysis shows that the enhanced tolerance of the transgenic rice to AS seems to be associated with the upregulation of the osmotic stress-related genes.
This study suggests that the ThPP1 gene plays an important regulatory role in conferring the tolerance of the transgenic rice to AS, and is a candidate in breeding for crop cultivation for alkaline tolerance.
For more on this study, read the article in Plant Cell Reports.
Seed germination begins the growth phases of plants and its rate is affected by plant hormones such as abscisic acid (ABA), gibberellin (GA) and brassinosteroids (BRs), as well as by environmental factors. The team of Ji-Hye Jang of Sookmyung Women's University in South Korea searched for additional reagents that may affect seed germination using the det2-1 and ga1-3 mutants, which showed reduced seed germination due to their defective BR- or GA- synthesis, respectively.
The team found that dithiothreitol (DTT) specifically enhanced seed germination of det2-1 mutant. The team then identified and focused on the Arabidopsis gene, AtGOLS1, as a differentially expressed gene between the mutants and those treated with DTT.
AtGOLS1 encodes a galactinol synthase, which is critical for the oligosaccharide synthesis during seed maturation. The expression of AtGOLS1 was found to decrease when conditions were favorable for seed germination. Furthermore, seed germination rate was faster in AtGOLS1-knockout mutants compared with wild type plants.
These results suggest that AtGOLS1 acts as a negative regulator in seed germination in Arabidopsis.
For more on this study, read the article in Plant Science.
CRISPR-Cas9 has been reported for precise genome modification in many plants. However, it has not been reported in banana. To prove this concept, researchers from the National Agri-Food Biotechnology Institute in India performed a mutation in the phytoene desaturase gene (RAS-PDS) of banana cv. Rasthali using the CRISPR-Cas9 system.
Two PDS genes, RAS-PDS1 and RAS-PDS2, were isolated from Rasthali and analysis confirmed that both PDS comprises conserved motifs for enzyme activity. A single guide RNA (sgRNA) was designed to target the conserved region of these two RAS-PDS genes and transformed with Cas9 in embryogenic cell suspension (ECS) cultures.
Complete albino and variegated phenotype were observed among the generated plantlets. DNA sequencing of 13 plants confirmed indels with a 59% mutation frequency in RAS-PDS. The decreased chlorophyll and total carotenoid contents were observed in mutant lines, revealing the functional disruption of both RAS-PDS genes.
These results demonstrate that genome editing through CRISPR-Cas9 can be applied for banana genome modification.
For more information, read the article in Functional & Integrative Genomics.
Lignin, a major component of the plant cell wall, stands as a barrier to efficient biofuel production from switchgrass (Panicum virgatum). While the advent of genome editing technologies offers new opportunities for improving switchgrass, its allotetraploidy (2n = 4x =36) may make it difficult to engineer.
The team of Jong-Jin Park of Oak Ridge National Laboratory developed a CRISPR-Cas9 genome editing system in switchgrass to target 4-Coumarate:coenzyme A ligase (4CL), a key enzyme involved in the early steps of the synthesis of monolignol, a component of lignin. Among the three 4CL genes identified in switchgrass, the Pv4CL1 transcripts were the most abundant.
Pv4CL1 was then selected as the target for CRISPR-Cas9 editing and a guide RNA was constructed to target it. Among the 39 genome-edited plants were generated, four plants were confirmed to have tetra-allelic mutations simultaneously. The Pv4CL1 knock-out plants had reduced cell wall thickness, a significant reduction in total lignin content, an increase in glucose release as well as an increase in xylose release.
This study established a success of CRISPR-Cas9 system in switchgrass. The system will be useful for decreasing the lignin content of lignocellulosic feedstock.
For more on this study, read the article in BMC Plant Biology.
Scientists at Salk Institute for Biological Studies have developed a new version of CRISPR-Cas9 genome editing technology that enabled them to activate genes without creating breaks in the DNA. This breakthrough has the potential to help human disease treatment using gene editing tools.
With the original CRISPR-Cas9 system, the process entails use of Cas9 enzyme together with guide RNAs that target the location where double strand breaks will be created. Recently, some scientists used a "dead" version of Cas9 which targets specific locations in the genome but no longer cuts the DNA. Instead, the dCas9 comes with molecular switches that turn on targeted genes. However, the dCas9 and its switches are too big to fit in the viruses used to deliver them into cells of living organisms.
Izpisua Belmonte and his team from Salk combined Cas9/dCas9 with various activator switches to search for a combination that worked even when the proteins were not fused to one another. Then, they packaged the Cas9 or sCas9 into one virus, and the switches and guide RNAs into another virus. As a proof of concept, they used their new approach to treat succesfully several diseases, including diabetes, acute kidney disease, and muscular dystrophy, in mouse models.
Watch the video from Salk for more information.
The latest addition to the VIB - International Plant Biotechnology Outreach (IPBO) Facts Series Sugarcane in Africa reviews the opportunities and challenges for sugarcane production in Sub-Saharan Africa. Ethanol production does not necessarily require additional cane production, or does not impact sugar production, because ethanol can be produced from sugarcane bagasse, which is an underutilized by-product of sugar factories. Cellulosic ethanol has the potential to nearly double the amount of fuel that can be produced without increasing the area planted with sugarcane and without competing with food security. The development of high sugar and biomass-yielding sugarcane is key for improving the value and sustainability of the sugarcane industry in Sub-Saharan Africa. To unlock sugarcane industry potential, a number of enabling conditions need to be reached vis-à-vis, for instance, environmentally sustainable production, infrastructure, trade policy, research and development, and financial services.
Get a copy from VIB.
ISAAA releases the updated series Biotech Crop Annual Updates and Biotech Traits Annual Updates. The Biotech Crop Annual Updates includes five short documents on biotech crops, namely: soybean, maize, cotton, canola, and alfalfa. Information in the series includes data on adoption, adopting countries, and the benefits of each biotech crop, based on ISAAA Brief 52: Global Status of Commercialized Biotech/GM Crops in 2016.
The Biotech Traits Annual Updates is a summary of traits deployed in biotech crops. The publication also includes a short discussion about the benefits of biotech crops with such traits, based from ISAAA Brief 52.
The documents are available for download from the ISAAA website.
News writers often solicit supporting information about their stories from various sources through interviews or readily-available references. The "voices" behind the stories usually have an impact on how stories are told.
The study Seventeen Years of Media Reportage of Modern Biotechnology in the Philippines, published in the April 2017 issue of the Philippine Journal of Crop Science, reported that Dr. Clive James, the Founder and Emeritus Chair of ISAAA, is the top source of information on biotechnology by news writers. The study analyzed articles reporting on modern agri-biotechnology that were released in major Philippine newspapers including Manila Bulletin, Philippine Star, Philippine Daily Inquirer and Business Mirror (for 2010-2016 only).
Read the complete post from the ISAAA Blog.