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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February 14, 2018
In This Week’s Issue:
News
Africa
• Nigeria is Gearing towards Commercializing GM Seeds
Americas
• Genetic Trigger Adds Branches to Plants, Could Boost Crop Yields
Asia and the Pacific
• Australian OGTR Approves GM Cotton (COT102) and Canola (DHA Canola)
• USDA FAS-GAIN Reports Advancement of Agri-biotech in Bangladesh
Europe
• Found: Gene that Confers Resistance to Septoria
• Temperature Resilient Crops Now an "Achievable Dream"
• German Study Analyzes Risk Perceptions of Consumers Regarding GM Crops
• Rice Gene Makes Maize Productive; To Do the Same for Other Crops
Research
• Scientists Conclude Safety of Pseudomonas as Source of Genes for GM Crops
• RTD1 Involved in Tocopherol Biosynthesis and Plant Development in Rice
New Breeding Technologies
• Researchers Test CRISPR-Cas9 on Red Sage
• OsPKS2 Controls Rice Male Fertility by Regulating Pollen Wall Formation
• TALENs-mediated Editing in Potato via Agroinfiltration
• Scientists Study the Function of OsPT4 in Arsenic Uptake in Rice
Beyond Crop Biotech
• Pheromone from Asian Citrus Psyllid that Transmits Citrus Greening Now Identified
• Scientists Sequence Genomes of 60 Citrus Varieties to Draw Up Family Tree and Understand Disease Response
• TcCHS Gene Confers Strong Resistance Against Cotton Aphids
Document Reminders
• Science and She Campaign
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NEWS
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Africa
NIGERIA IS GEARING TOWARDS COMMERCIALIZING GM SEEDS
In Nigeria, local seed companies have a strategic role to play in the multiplication and distribution of seeds to farmers when GM seeds become available in the market. This was according to Dr. Rose Gidado, assistant director of the National Biotechnology Development Agency (NABDA).
The biosafety law of Nigeria was put in place in 2015, followed by the establishment of the National Biosafety Management Agency (NBMA), which has been in charge of implementing biosafety regulations. According to NBMA, the country is ripe for commercialization of GM products. This may imply that Nigeria will soon start the commercialization of staple crops that have been tested through confined field trials such as the Maruca-resistant cowpea currently being tested by farmers on the fields, and Bt cotton, which is on general release.
"When GM seeds are finally commercialized, our indigenous seed companies have a very key role to play in the commercialization and multiplication of seeds. Of course, they have to take over, it is not the foreign seed companies that will determine, even if the foreign seed companies are going to be part of it, they are going to work hand in hand with our local seed companies, build their capacities and all that," said Dr. Gidado, who is also the country coordinator of the Open Forum on Agricultural Biotechnology (OFAB) Nigeria chapter. She added that local seed companies were already being engaged and sensitized about their part in multiplication and distribution of the seeds.
Read the original article from Leadership Nigeria.
Plants cannot make unlimited number of branches -- a gene puts the brakes on this process called shoot branching. A group of researchers, though, reveals a chemical that can reverse this limitation, possibly leading to improved crop production.
A regulator gene called D14 was identified in previous studies about shoot branching. Shinya Hagihara, Yuichiro Tsuchiya and colleagues reasoned that if they could inhibit this regulator, they could do the opposite and increase branching. The research teams developed a screen to monitor shoot branching activity based on whether a reporter chemical called Yoshimulactone Green (YLG) glowed green.
By screening a library of 800 compounds, the researchers found that 18 of them inhibited D14 by 70 percent or more. One of these is called DL1, and could increase shoot branching in both a type of flower and in rice. The team is now testing how long the chemicals last in the soil and are investigating whether it is toxic to humans.
For more details, read the news release from The American Chemical Society.
The Australian Office of the Gene Technology Regulator (OGTR) announced the approval for commercial release of insect resistant cotton (COT102) and GM canola with improved omega-3 oil content (DHA canola).
According to the OGTR notices, COT102 and DHA canola, as well as the products derived from them, may enter general commerce, including use in human food and animal feed. Food Standards Australia New Zealand (FSANZ) has approved the use in food of material derived from these events. The approval was granted based on the finalized Risk Assessment and Risk Management Plan (RARMP), which concluded that the commercial release of COT102 and DHA canola pose negligible risks to people and the environment and does not require specific risk treatment measures.
Read the OGTR notice for GM cotton and GM canola for more details.
The USDA FAS Global Agricultural Information Network released updates on the status of agricultural biotechnology in Bangladesh. According to the report, biotech research is advancing moderately in Bangladesh particularly in several crops with support from policymakers, regulators, and development partners.
The country's objective is to ensure food security and safety through development of biotech and abiotic stress tolerant crops with lower production costs. This supportive stance of the government creates a positive impact towards research, encouraging scientists to develop new varieties using biotechnology. The regulatory system is consistently adjusting to keep pace with biotech research and development, and to speed up the commercialization of GM products.
Download the report for more details.
Researchers have, for the first time, isolated a gene that will give wheat a natural resistance to Septoria tritici blotch (STB, or Septoria). Septoria is the main leaf disease of wheat in temperate regions and a major threat for wheat production globally, capable of halving crop yields. The disease is caused by the fungal pathogen Zymoseptoria tritici.
The gene, called Stb6, has been known for 20 years, but its mapping and isolation took five years to complete by a research team led by Kostya Kanyuka at Rothamsted Research and Cyrille Saintenac at the National Institute for Agricultural Research (INRA).
Kanyuka said that the Stb6 gene is effective against only a fraction of fungal strains, specifically those that secrete a matching protein, called AvrStb6. The Stb6 protein somehow recognizes this fungal protein, which leads to activation of the defense response in wheat.
For more information about this research, read the Rothamsted Research News.
A new study reveals that breeding temperature resilient crops can now be achieved. A research conducted at John Innes Centre (JIC) has established a genetic link between increased temperature and the problem of "pod shatter" (premature seed dispersal) in oilseed rape. The research, led by Dr. Vinod Kumar and Professor Lars Østergaard, reveals that pod shatter is enhanced at higher temperature across diverse species in the Brassicaceae family which also includes cauliflower, broccoli, and kale.
To study the effects of temperature on seed dispersal, Dr. Xinran Li, a postdoctoral researcher, monitored fruit development in Arabidopsis at three different temperatures 17, 22 and 27 degrees centigrade. This showed that cell wall stiffened at the tissue where pod shatter takes place, was enhanced by increasing temperature, and occurs across the Brassicaceae family, including oilseed rape.
The team established the genetic mechanism which organizes plant response to higher temperatures. Previous studies have shown that pod shatter is controlled by a gene called INDEHISCENT (IND). This study reveals that IND is under the control of a thermo-sensory mechanism in which a histone called H2A.Z is a key player.
For more, read the JIC News.
Consumers are more concerned about potential environmental risks of GM crops than health worries, according to a study conducted in Germany. The results are published in the International Journal of Consumer Studies.
The research team, composed of scientists from the University of Bonn and Swedish University of Agricultural Sciences, aimed to investigate the risk perceptions of 439 German consumers regarding genetic engineering. The subjects were divided into four experimental treatment groups comprised of two policy scenarios, one only permitting research and development and the other allowing full commercialization of GM products, and two product end-uses, bioenergy and food.
Results showed that health risks were generally perceived to be lower for GM crops used for bioenergy than for food. Full commercialization of GM food prompted higher concerns about personal health, while use of crops for bioenergy was linked to higher levels of socioeconomic risk. Even if most of the consumers said that health risk is the most relevant for them, the consequences for the environment evoked the most degree of perception.
Read more about the study in the International Journal of Consumer Studies.
In field trials three years ago, biotechnologists showed that they could increase maize productivity by introducing a rice gene into the plant that regulated the accumulation of sucrose in kernels, which also led to more kernels per maize plant. This promising technique is set to do the same for other crops, including wheat and rice.
The rice gene affected the performance of a natural chemical in maize, trehalose 6-phosphate (T6P), which influences sucrose distribution in the plant. But they were keen to discover more intimate details of the relationships governing the increased productivity.
The transgenic maize depressed levels of T6P in the phloem, a major component of the plant's transportation network. This allows more sucrose to move to developing kernels and, serendipitously, increasing rates of photosynthesis, thereby producing even more sucrose for more kernels. The team also looked at the phloem within the plant's reproductive structures which are sensitive to drought. Female kernels abort, but keeping sucrose flowing within the structures prevents this abortion.
More details are available at Rothamsted Research News.
Scientists from DuPont Pioneer, USA, investigated the safety of bacterium Pseudomonas chlororaphis as gene source for genetically modified crops. The results are published in an open-access article in Transgenic Research journal.
GM crops go through rigorous science-based assessment process to characterize their food, feed, and environmental safety before commercialization. The process of safety assessment entails various steps such as evaluation of each introduced trait, including its source organism, for any possible unwanted effects. Scientists have shown that Pseudomonas species have been safely applied in agriculture and some have been a good source of genes with insecticidal characteristics. In particular, P. chlororaphis has an ipd072Aa gene, which expresses a protein that confers protection against specific coleopteran pests when transformed in maize.
According to the paper, P. chlororaphis is widely present in the environment and has no known toxic or allergenic properties based on previous assessments. It is distantly related to plant and human pathogens, but has a long history of safe use. Thus, it can be a good candidate as source of genes for developing insect resistant crops.
Read the research article in Transgenic Research.
Tocopherols are one of the most important antioxidants with roles in living organisms. The functions of tocopherols have been characterized in animals and artificial membranes. However, the genetic and molecular functions of tocopherols in plants are less understood. The team of Yunhui Zhang from Jiangsu Academy of Agricultural Sciences aims to study a tocopherol-deficient mutant rice, rtd1.
The rtd1 mutant showed overall growth retardation throughout its growth period. Most of the agronomic traits were also impaired in rtd1. Analysis revealed that the RTD1 gene encoded homogentisate phytyltransferase, an enzyme catalyzing a key step in tocopherol biosynthesis. RTD1 was also found to be expressed in green leafy tissues, and the protein was located in chloroplasts. Cold tolerance was also found to be reduced in the rtd1 mutant.
The rtd1 mutant also exhibited a reduced response to gibberellin (GA). However, the GA content was not changed, suggesting a transcriptional regulation of SLR1.
These findings implied that tocopherols play important roles in regulating rice growth and development.
For more information, read the article in Plant Cell Reports.
The CRISPR-Cas9 system is a powerful genome editing tool that has been used in many species. However, it has never been applied on red sage (Salvia miltiorrhiza), a traditional Chinese medicinal herb. To test the CRISPR-Cas9 system's applicability in red sage, the team of Zheng Zhou from the Second Military Medical University in China focused on its rosmarinic acid synthase gene (SmRAS) of red sage.
A single guide RNA (sgRNA) was designed to edit the SmRAS gene. Five biallelic mutants, two heterozygous mutants and one homozygous mutant were obtained. Analysis showed that the contents of phenolic acids, including rosmarinic acid, and the expression level of SmRAS were decreased in the successfully edited lines, particularly in the homozygous mutants. Furthermore, the level of the rosmarinic acid precursor clearly increased.
These results indicate that the CRISPR-Cas9 system can be used to identify important genes and that this technology is an efficient tool for genome editing in red sage. This system presents a promising potential method to improve the quality of traditional Chinese medicinal herbs.
For more information, read the article in Phytochemistry.
The pollen wall protects male gametes from various environmental stresses and pathogen attacks, as well as promotes pollen germination. The synthesis of sporopollenin is critical for pollen wall formation. Recently, sporopollenin metabolism has been studied in pollen wall development in Arabidopsis. However, little is known about the sporopollenin synthesis in pollen wall formation in rice (Oryza sativa).
The team of Ting Zou of Sichuan Agricultural University in China identified that a point mutation in OsPKS2, a polyketide synthase gene, can cause male sterility in rice by affecting the normal progress of pollen wall formation. The team used CRISPR-Cas9 system to develop allelic mutants of OsPKS2. The resulting lines were observed to be completely male sterile.
This result confirms that OsPKS2 controls rice male fertility and suggest that it is critical for pollen wall formation.
For more information, read the article in Plant Cell Reports.
A rapid test and an effective delivery system for introducing TALENs to plants are critical for successful target mutation. TALENs have usually been tested in protoplasts or introduced to plants with viral vectors. However, plant regeneration from protoplast culture can be unreliable. Viral vectors are not always available, and plants edited by these vectors require virus elimination.
Jin Ma from the Fredericton Research and Development Centre in Canada used a non-viral, Agrobacterium-mediated transient expression approach, to serve as both a rapid test and an effective delivery of TALENs into two vegetatively propagated potato (Solanum tuberosum) cultivars. Two TALENs were expressed to target two genes, one for a starch branching enzyme, and one for an acid invertase, into leaves of potato plants via agroinfiltration.
The infiltrated leaf DNA was analyzed and revealed that the two TALENs successfully agroinfiltrated and induced mutations at both targeted loci.
For more information on this study, read the article in Plant Biotechnology Reports.
Arsenic (As) is toxic to organisms, and elevated As accumulation in rice (Oryza sativa) grain poses a significant health risk to humans. The predominant form of As in soil under aerobic conditions is As(V). Rice roots take up As(V) by phosphate (Pi) transporters, such as OsPT1 and OsPT8. Ying Ye from Huazhong Agricultural University in China investigated the contribution of OsPT4 on rice As(V) uptake and transport.
Ying's team determined that the mRNA amounts of OsPTs in rice seedlings, and expressions of OsPT1, OsPT4, and OsPT8 were upregulated under As(V) conditions. OsPT4-overexpressing plants were obtained to examine the As(V) transport activity in rice. The transgenic rice showed sensitivity to As(V) stress with aboveground parts showing delayed growth and the roots stunted. The team also used CRISPR-Cas9 and targeted the OsPT4 gene, developing knockout lines. The knockout lines showed the opposite phenotype compared to the overexpressing lines.
The study indicates that OsPT4 is involved in As(V) uptake and transport and could be a good candidate gene to generate low As-accumulating rice.
For more information, read the article in Frontiers in Plant Science.
Huanglongbing (HLB), also known as citrus greening, is a devastating disease of citrus worldwide. Once infected, citrus trees must be eradicated. In Brazil, as much as 46.2 million citrus trees (or 26% of the currently planted trees) have been eradicated since HLB was detected in 2004.
HLB is caused by bacteria of the genus Candidatus liberibacter spp., which are transmitted from tree to tree by the Asian citrus psyllid (Diaphorina citri) in Asia and America and the African citrus psyllid (Trioza erytreae) in Africa.
Researchers have now identified and synthesized D. citri's sex pheromone for use as bait in traps to lure the insects and kill them before mating. Analysis of isolated compounds revealed that the main component of the sex pheromone released by virgin females was lignoceryl acetate.
For more details, read the research findings published in Scientific Reports.
Citrus is one of the world's best-loved fruit, but the crop has been beset by Huanglongbing (a.k.a., citrus greening), an infectious disease destroying whole orchards. Researchers are now using genomics to better understand how citrus varieties respond to disease and other stresses.
A global team of scientists sequenced the genomes of 60 citrus varieties to draw up a family tree and investigate the genetic diversity and evolutionary history of citrus. The team led by researchers at the Joint Genome Institute (JGI), the Instituto Valenciano de Investigaciones Agrarias in Spain, and the Citrus Research and Education Center of the University of Florida, has now proposed a revised genealogy of the major citrus cultivars and traced the origin of citrus back to the Himalayan foothills.
The study states that citrus originated in an area limited by Eastern India, Northern Myanmar, and Western Yunnan during the late Miocene. The first attempts at domesticating these fruits are thought to be by asexual propagation through apomictic seeds and the deliberate selection for specific traits which generated a complex network of relatedness among cultivated citrus that is recorded in the genomes. Southeast Asia has long been considered the birthplace of citrus, and the citrus plants are thought to have then migrated across Asia, reaching Australia around 4-5 million years ago, during the early Pliocene period.
For more information, visit JGI.
Aphids are pests of chrysanthemum that use plant volatiles to select host plants. They ingest cell contents to test the quality of the host before engaging in prolonged feeding and reproduction. Changes in metabolite profiles can disrupt aphid–plant interactions and provide new methods of pest control.
To test this theory, Hao Hu of Huazhong Agricultural University in China and Wageningen University in the Netherlands overexpressed the dalmatian pyrethrum (Tanacetum cinerariifolium) TcCHS gene, encoding chrysanthemol synthase, in chrysanthemum (Chrysanthemum morifolium).
Overexpression resulted in the transgenic chrysanthemum emitting volatile chrysanthemol, with no detrimental phenotypic effects. Analysis showed that the TcCHS-overexpressing plants significantly reduced aphid reproduction, consistent with disturbance of aphid probing activities on these plants. In open-field trials, aphid population development was very strongly impaired demonstrating the robustness and high impact of the trait.
These results suggest that expression of the TcCHS gene can induce a defense system. This study also introduces a promising new option for engineering aphid control into plants.
For more information on this study, read the article in Plant Biotechnology Journal.
Female scientists and science communicators from Asian and African countries have started a campaign called Science and She, which aims to empower women to speak up for science and help bridge the gap between the technical field and the public.
For each week, one scientist or science communicator will serve as the curator of the Science and She social media pages, and tell her stories and aspirations for science and the society. For this week, Dr. Rhodora Romero-Aldemita, Director of ISAAA Global Knowledge Center on Crop Biotechnology, shares the importance of hard work and accomplishments to gain the trust of the public on science.
Women in the field of science are encouraged to follow the campaign by sharing the posts and join the interactive group of empowered women in science.
Follow Science and She on Facebook, Twitter, and Instagram to join the campaign.