Researchers at Cold Spring Harbor Laboratory (CSHL) have identified a relationship between maize crop yield and the specific genetic activity associated with one of the plant's metabolic pathways. 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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April 10, 2019
In This Week’s Issue:
News
Global
• Durum Wheat Genome Decoded
Africa
• Scientists Use Plant Hormones to Fight a Parasitic Crop Pest in Africa
Americas
• The Search for New Sources of Salt Tolerance in Carrots
• Scientists Pinpoint Gene Vital for Making Maize Ears
• Maize Yields Influenced by Unexpected Gene 'Moonlighting'
Asia and the Pacific
• Scientists Develop Model that Predicts Photosynthetic Manipulations to Increase Yields
• Agri-biotech Stakeholders Convene for Pan-Asia Farmer's Exchange Program
Europe
• Two Studies Reveal Steps in Plant Immune Receptor Activation
• EFSA Releases Scientific Opinion on Six-Event GM Maize
Research
• Study Explains Why Plants Grow Less in Hot Environments
• Vietnamese Scientists Develop Drought Tolerant Rice Lines
New Breeding Technologies
• Blight Disease Resistance of TBR225 Rice Variety
• Study Shows Single and Multiple Gene Knockouts by CRISPR-Cas9 in Maize
Beyond Crop Biotech
• Scientists Genetically Engineer Yeast to Improve Understanding of How Cells Work
Announcements
• Register to Plant Genomics and Gene Editing Congress: Asia (10% Discount for CBU Subscribers)
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NEWS
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Global
DURUM WHEAT GENOME DECODED
Researchers composed of more than 60 scientists from seven countries have published the results of their study detailing the sequence of the durum wheat genome. By comparing the durum wheat to its wild relative, the researchers were able to examine the order and structure of its genes. They were then able to look at the gene's blueprint that lead them to quickly identify which genes are responsible for the different specific desirable plant traits. According to one of the scientists, identifying the gene's DNA signatures is critical to the evolution and breeding of the durum wheat, as they are now able to understand which combination of genes is driving a specific signature that needs to be focused on and maintained during breeding. They were also able to uncover and map areas of genetic diversity loss that resulted in recovering beneficial genes lost during centuries of breeding.
Further investigation also allowed researchers to locate the gene responsible for the accumulation of cadmium. They then discovered how to significantly reduce cadmium levels in the grain to ensure the wheat's safety and nutritional value based on the World Health Organization's standards.
Durum wheat is mainly used as the raw material for pasta and couscous production, and is one of the food staples of today's population. The demand for more, safer and higher-quality durum wheat has been increasing over the years. The significance of the study allows future scientists to explore the genetics of the durum wheat's genetics of gluten proteins and the factors that control its nutritional properties.
See the complete details of the study in Nature Genetics.
Striga hermonthica, also known as purple witchweed, is an invasive parasitic plant threatening sub-Saharan Africa's food production. Striga infects the region's staple crops such as pearl millet, sorghum, and other cereal crops.
Striga has an Achilles heel, though. As a parasite that attaches to the roots of other plants, it dies when it cannot find a host plant to attach to. Scientists found a way to exploit Striga's Achilles' heel to eradicate it from farmers' fields. A research team from the King Abdullah University of Science and Technology found that they could trick Striga seeds to think that a host plant grows nearby. Striga seeds germinate, but do not survive without a host plant to attach to.
The scientists use plant hormones exuded by plant roots called strigolactones. These hormones trigger Striga seeds to germinate. By treating bare crop fields in Burkina Faso with artificial strigolactones, the scientists found that they were able to reduce the number of Striga plants by more than half. This method will allow farmers and scientists to work together to fight the spread of Striga plant, protecting the food security of 300 million people in the region.
More details are available in the paper published in Plants, People, Planet.
Scientists from the University of Wisconsin assessed the diverse carrot germplasm's response to salinity stress and identified the salt-tolerant carrot germplasm that may be used by breeders. They also defined the appropriate screening criteria for assessing salt tolerance in germinating carrot seed. Their research is published in HortScience.
Lead scientists Adam Bolton and Philipp Simon emphasized that one of the effective ways to combat the effects of salinity stress in glycophytic crops like carrot is by identifying new genetic sources of tolerance and efficient phenotypic methods to develop salinity-tolerant cultivars.
"In previous studies, carrots have been characterized as a crop that is sensitive to salinity. This study evaluated a large collection of wild and cultivated carrot germplasm and confirmed that, in fact, many carrot cultivars are saline-sensitive during seed germination, but that many germplasm accessions evaluated were quite saline-tolerant. Interestingly, many of the more saline-tolerant carrots evaluated were cultivated carrots, perhaps reflecting unintentional selection by farmers that have been growing the crop with saline irrigation water. This study provides an optimistic outlook for breeding carrots with improved salinity tolerance during germination. Tolerance during seeding and later plant development will also be needed as salinity becomes a more serious challenge for farmers," Simon said.
Read the research article in HortScience.
How do maize plants form their ears? This question was answered by a team of scientists from the University of Missouri led by maize geneticist Paula McSteen through their study that helped identify the specific gene vital for forming the ears in maize. The results of their study are published in Molecular Plant.
The research team found that the gene known as barren stalk 2 (ba2) has an impact on the development of axillary meristems, which are special cells that give rise to the ears. To pinpoint the genes needed to produce the ears, the researchers looked for plants that cannot make the organ properly. They found that plants with mutations in ba2 never make ears, thus its name. The mutant plants do not have grooves where the ears would form, which imply that the gene functions early, before the ear bud forms. Then the ba2 mutant was discovered in a large genetic screen for maize plants not able to grow ears, and the gene was identified through molecular mapping.
Additional tests further showed that ba2 is linked with other genes that regulate ba1. Together, these findings how that ba2 is in the same molecular signaling pathway as ba1 and the two genes work together to regulate ear development.
Read more from the University of Missouri.
Researchers at Cold Spring Harbor Laboratory (CSHL) have identified a relationship between maize crop yield and the specific genetic activity associated with one of the plant's metabolic pathways.
Maize ears are normally not branched, and form one straight cob. However, maize mutants that don't have the RAMOSA3 gene end up with gnarly-looking branched ears. Professor David Jackson and his team at CSHL have connected the RAMOSA3 gene to branching, which can affect maize yields. When a maize plant has too many branches, it expends more energy towards making those branches, and less towards making seeds. More branches often means lower yields.
Professor Jackson and his team initially hypothesized that the enzyme that RAMOSA3 encodes, called TPP, and a sugar phosphate called T6P which TPP acts on, are likely responsible for the ear-branching. In a surprising twist, they found that a related gene, TPP4, also helps to control branching, but that gene's effect was unrelated to its enzymatic activity. To follow up on this, they blocked only the enzyme activity associated with RAMOSA3, and not the gene itself, and got normal-looking ears of maize. This indicates that although RAMOSA3 controls the activity of the enzyme, the enzyme activity is not responsible for branching. Thus, the gene may be "moonlighting" with a hidden activity, explains Jackson.
For more details, read the CSHL news article.
A research team from Australia's ARC Centre of Excellence for Translational Photosynthesis (CoETP) has developed a dynamic model that predicts which photosynthetic manipulations to plants will boost the yields of wheat and sorghum. Crop yields need to increase to feed the growing global population.
Lead author Dr. Alex Wu said the prediction tool will help find new ways to improve yields of crops around the world. He added that the modelling tool has the capacity to link across biological scales from biochemistry in the leaf to the whole field crop over a growing season, by integrating photosynthesis and crop models.
According to Centre Deputy Director Professor Susanne von Caemmerer, one of the study's most innovative aspects was using a cross-scale modelling approach to look at the interactions between photosynthesis and the pores of the leaf that allow the exchange of CO2 and water vapor. The team looked at three main photosynthesis manipulation targets – enhancing the activity of the main photosynthetic enzyme, Rubisco; improving the capacity of the leaves to transport electrons; and improving the flow of carbon dioxide (CO2) through the internal layers of the leaf.
For more details, read the news article in CoETP.
Forty-three delegates from 10 Asian countries composed of farmer-leaders, scientists and the academia, media, as well as representatives from government and private institutions gathered for the week-long 13th Pan-Asia Farmers' Exchange Program held on April 1-5, 2019 in Manila, Philippines.
Discussions focused on communicating biotech in the Philippines, the country's biosafety regulations for biotech crops, insect resistance management program, the current status of agri-biotech in each country, and plant breeding innovations. The group also went to a commercial Bt corn farm in the province of Tarlac and paid a visit to the International Rice Research Institute as well as the Corteva Seed Processing Plant to learn about their projects and see the research facilities first-hand.
The exchange program, which was first conducted in 2007, was organized by CropLife Asia, CropLife Philippines, and the Biotechnology Coalition of the Philippines. It aims to serve as a platform for knowledge sharing and exchange on agricultural biotechnology where the delegates learn how biotech crops go through a stringent, science-based regulatory process to ensure their safety to humans and animals and to the environment, how they are managed at farm level, and how they benefit the farmers and their communities.
For more details about biotechnology developments in the Philippines, visit the SEARCA BIC website.
Two studies conducted in the laboratory of Alexander von Humboldt Professor Jijie Chai at the Max Planck Institute for Plant Breeding Research provide unprecedented structural insight into how plant immune receptors are primed and activated to provide plants with resistance against microbial pathogens.
An important plant mechanism is defined by cytoplasmic receptors called NLRs that recognize effectors, the molecules that invading microorganisms secrete into the plant's cells. These recognition events can either involve direct recognition of effectors by NLRs or indirect recognition, in which the NLRs act as ‘guards' that monitor additional host proteins or ‘guardees' that are modified by effectors.
The studies by Jijie Chai together with research teams from Tsinghua University and the Chinese Academy of Sciences have now pieced together the sequence of molecular events that convert inactive NLR molecules into active complexes that provide disease resistance.
The researchers looked at the protein called ZAR1, an ancient plant molecule capable of indirectly sensing several unrelated bacterial effectors. They observed that in the absence of bacterial effectors, ZAR1, together with RKS1, stays in a latent state through interactions involving multiple domains of the ZAR1 protein. Upon infection, a bacterial effector modifies the plant ‘guardee' PBL2, which then activates RKS1 resulting in huge conformational changes that first allow plants to swap ADP for ATP and then result in the assembly of a pentameric, wheel-like structure that the authors term the ‘ZAR1 resistosome'.
For more details, read the news release from Max Planck Institute for Plant Breeding Research.
The European Food Safety Authority (EFSA) Panel on Genetically Modified Organisms (GMO Panel) has published the Scientific Opinion on the safety of six-event stack genetically modified (GM) maize Bt11 × MIR162 × MIR604 × 1507 × 5307 × GA21 and its subcombinations independently of their origin. The scientific opinion is published based on the application EFSA‐GMO‐DE‐2011‐103 under Regulation (EC) No. 1829/2003 from Syngenta Crop Protection AG.
The scope of application EFSA‐GMO‐DE‐2011‐103 is for food and feed uses, import and processing in the European Union of the GM herbicide‐tolerant insect‐resistant maize Bt11 × MIR162 × MIR604 × 1507 × 5307 × GA21 and all its subcombinations independently of their origin. The GMO Panel has previously assessed the six single events and 22 of their subcombinations and did not identify safety concerns. No new data on the single events or their 22 combinations that could lead to modification of the original conclusions on their safety were identified. The GMO Panel concludes that the six‐event stack maize is as safe as and nutritionally equivalent to its non‐GM comparator and the non‐GM reference varieties tested.
For more details, read the scientific opinion in the EFSA Journal.
Plants have developed a complex system that when exposed to extreme environments such as hot temperatures, their energy is diverted towards survival instead of being used for growth. Scientists from Nara Institute of Science and Technology (NAIST) in Japan reported that two transcription factors, ANAC044 and ANACO85, are vital in such mechanism in Arabidopsis, and this provides clues on how to modulate growth of important agricultural crops. The results of their study is published in eLife.
In previous studies, NAIST Professor Masaaki Umeda and team reported that SOG1 is activated by DNA damage and regulates almost all genes induced by the damage, while Rep-MYBs are stabilized in DNA damage conditions to suppress cell division. In the latest study, Umeda's research team shows that ANAC044 and ANAC085 act as a bridge between SOG1 and Rep-MYB. They found that ANAC044 and ANAC085 are essential for root growth retardation and stem cell death, but not for DNA repair. Specifically, ANAC044 and ANAC085 were responsible for preventing the cell cycle from proceeding from G2 phase to mitosis in response to the DNA damage. This implies that ANAC044 and ANAC085 serve as gatekeepers in the progression from the G2 phase in the cell cycle under abiotic stress conditions.
The study shows a new mechanism that optimizes organ growth under stressful conditions. Thus, the researchers recommend other scientists to consider ANAC044 and ANAC085 in increasing plant productivity.
For more details, read the original article from NAIST and the research article in eLife.
Gene encoding DREB1A transcription factors from other plants, including Arabidopsis, corn, canola, barley, rice, tomato, and wheat have been cloned and many studies proved expression of DREB1A increase drought tolerance in transgenic plants. In a previous study, MtOsDREB1A gene was isolated and the OsDREB1A gene was successfully transformed into the Chanh Trui rice variety. The results are published in the Journal of Agriculture and Rural Development.
Results showed that the four lines of the transgenic plants maintained the transgene up to the T3 generation. After three weeks of drought or no water supply, the transgenic rice lines showed the ability to recover. Expression test results showed that OsDREB1A and some drought tolerant indicator genes in transgenic plants had enhanced expression under drought conditions. The results of the study showed that enhancement of OsDREB1A expression is correlated with enhanced expression of control genes and related drought tolerance of the transgenic lines.
Read the original article in Vietnamese in the Journal of Agriculture and Rural Development.
OsSWEET family encodes sugar transporters which are involved in the bacterial leaf blight (BLB) disease. In a study published in the Journal of Agriculture and Rural Development, promoter OsSWEET14 was isolated from Xanthomonas oryzae pv. oryzae (Xoo) susceptible TBR225 rice variety. The 1392-bp isolated DNA sequence contains four cis acting elements recognized specifically by Xoo TAL proteins, including TalC, Tal5, PthXa3 and AvrXa7. OsSWEET14-TBR225 showed the similarity of 99% and 100% to OsSWEET14 of GeneBank-registered Japonica (Niponbare, AP014967.1) and Indica (Shuhui498, CP018167.1) varieties, respectively. Based on the isolated DNA sequence, three gRNAs were designed for modifying the TAL effector binding sites on the OsSWEET14 promoter and knockouting the OsSWEET14 gene using CRISPR-Cas9 technology in order to enhance the resistance of TBR225 rice veriety.
The research can be used as basis for generating BLB disease resistant and high yielding rice varieties using genome editing technology in Vietnam.
For more information, read the article in Vietnamese in the Journal of Agriculture and Rural Development.
Scientists from Institut National de la Recherche Agronomique in France together with partners in Italy reported single and multiple gene mutagenesis using stably transformed plants. The findings are published in Plant Cell Reports.
The team used two different CRISPR-Cas9 vectors allowing the expression of multiple guide RNAs and various techniques to knockout either independent or paralogous genes. They generated 12 plasmids that represent 28 various single guide RNAs (sgRNAs) to target 20 genes. For 18 of the target genes, at least one mutant allele was obtained, while two genes were recalcitrant to sequence editing.
It was observed that there were small insertions or deletions of less than ten nucleotides, regardless of whether the gene was targeted by one or more sgRNAs. They also found deletions of defined regions located between the target sites of two guide RNAs. Furthermore, double and triple mutants were created in a single step, which is important for functional analysis of genes with strong genetic linkage. Tests also showed that the majority (85%) were fully edited plants transmitting systematically all detected mutations to the next generation, generally following Mendelian segregation.
Read the research article in Plant Cell Reports.
Researchers from the University of Cambridge and Imperial College London, together with AstraZeneca, have used mathematical modelling and genome engineering to edit yeast cells to help scientists control not just what the cells sense but how they react to what they sense in a more desirable way.
Yeast senses its environment using G protein-coupled receptors (GPCRs). GPCRs enable cells to sense chemical substances such as hormones, poisons, and drugs in their environment. They can also act as light, smell, and flavor receptors. The Cambridge team developed a mathematical model of the yeast cell with varied concentrations of different cell components and found the optimum levels for the most efficient signalling of each one. This information was then used by researchers at Imperial College London to genetically modify cells.
Dr. William Shaw, a researcher at Imperial College London said the new information enabled them to understand exactly how to genetically engineer a cell so it senses something in a way that can be controlled. Through the computational findings, the team created a highly-modified strain of yeast with all the non-essential interactions within the GPCR signalling pathway removed. This allowed them to predictably alter the way cells responded to their environment.
For more details, read the news release from the University of Cambridge.
Over the recent years, plant research and its associated technologies have improved drastically as a result of revolutionary breakthroughs such as new gene editing technology and the reduction in the cost of sequencing. As a result of many plants have now been successfully sequenced and a wide range of biological data-set made available, plant scientists are now making use of state of the art technology platforms to help explain biological principals, advance research and therefore enable benefits such as crop improvement and breeding techniques.
Meanwhile, the mass variety of microbes within the plant and soil are not only crucial in plant growth, yield & health, but also in pest management and fixation cycles. The crop quality improving technologies and the new pest control technologies are now becoming important tools to farmers.
This year, Global Engage, the University of Nottingham (Malaysia), and Crops for the Future, are pleased to announce that the congress is co-located with Microbiome for Agriculture Congress Asia 2019. This congress is part of our highly respected Plant Genomic Series held in Europe each May and the US every September each year.
Specific focus areas to be tackled in the congress include: