A Tobacco Homolog of DCN1 is Involved in Cellular Reprogramming and in Developmental Transitions

Plant proteomes show remarkable plasticity in reaction to environmental challenges and during developmental transitions. Some of this adaptability comes from ubiquitin-mediated protein destruction regulated by cullin-RING E3 ubiquitin ligases (CRLs). CRLs are activated through modification of the cullin subunit with the ubiquitin-like protein RUB/NEDD8 by an E3 ligase called defective in cullin neddylation 1 (DCN1). Here we show that tobacco DCN1 binds ubiquitin and RUB/NEDD8, and associates with cullin. When knocked down by RNAi, tobacco pollen formation stopped and zygotic embryogenesis was blocked around the globular stage. Additionally, we found that RNAi of DCN1 inhibited the stress-triggered reprogramming of cultured microspores from their intrinsic gametophytic mode of development to an embryogenic state. This stress-induced developmental switch is a known feature in many important crops and leads ultimately to the formation of haploid embryos and plants. Compensating the RNAi effect by re-transformation with a promoter-silencing construct restored pollen development and zygotic embryogenesis, as well as the ability for stress-induced formation of embryogenic microspores. Overexpression of DCN1, however, accelerated pollen tube growth and increased the potential for microspore reprogramming. These results demonstrate that the biochemical function of DCN1 is conserved in plants and that its activity is specifically required for transitions during pollen development and embryogenesis, and for pollen tube tip growth

Detection Methods Fit-for-Purpose in Enforcement Control of Genetically Modified Plants Produced with Novel Genomic Techniques (NGTs)

The comprehensive EU regulatory framework regarding GMOs aims at preventing damage to human and animal health and the environment, and foresees labelling and traceability. Genome-edited plants and products fall under these EU GMO regulations, which have to be implemented in enforcement control activities. GMO detection methods currently used by enforcement laboratories are based on real-time PCR, where specificity and sensitivity are important performance parameters. Genome editing allows the targeted modification of nucleotide sequences in organisms, including plants, and often produces single nucleotide variants (SNVs), which are the most challenging class of genome edits to detect. The test method must therefore meet advanced requirements regarding specificity, which can be increased by modifying a PCR method. Digital PCR systems achieve a very high sensitivity and have advantages in quantitative measurement. Sequencing methods may also be used to detect DNA modifications caused by genome editing. Whereas most PCR methods can be carried out in an enforcement laboratory with existing technical equipment and staff, the processing of the sequencing data requires additional resources and the appropriate bioinformatic expertise

Genome-Edited Plants: Opportunities and Challenges for an Anticipatory Detection and Identification Framework

It is difficult to trace and identify genome-edited food and feed products if relevant information is not made available to competent authorities. This results in major challenges, as genetically modified organism (GMO) regulatory frameworks for food and feed that apply to countries such as the member states of the European Union (EU) require enforcement based on detection. An international anticipatory detection and identification framework for voluntary collaboration and collation of disclosed information on genome-edited plants could be a valuable tool to address these challenges caused by data gaps. Scrutinizing different information sources and establishing a level of information that is sufficient to unambiguously conclude on the application of genome editing in the plant breeding process can support the identification of genome-edited products by complementing the results of analytical detection. International coordination to set up an appropriate state-of-the-art database is recommended to overcome the difficulty caused by the non-harmonized bio-safety regulation requirements of genome-edited food and feed products in various countries. This approach helps to avoid trade disruptions and to facilitate GMO/non-GMO labeling schemes. Implementation of the legal requirements for genome-edited food and feed products in the EU and elsewhere would substantially benefit from such an anticipatory framework

Farmers Feel the Climate Change: Variety Choice as an Adaptation Strategy of European Potato Farmers

Effects associated with a changing climate could severely threaten potato production in Europe. Hence, farmers need to take up adaptation measures to safeguard agricultural production. Collecting data from 553 farmers from 22 different European countries, our survey evaluates European potato farmers’ perceptions regarding the influence of climate change on local potato production, and their willingness to implement adaptation strategies. An overwhelming majority of survey respondents had already experienced the effects of climatic changes on their potato production. Specifically, drought and heat were identified as the most significant threats. The planting of an adapted variety was the preferred adaptation strategy, while farmers were also willing to take up changes in agricultural management practices. Survey respondents predominantly considered yield stability as the most important characteristic of an adapted variety, closely followed by heat tolerance, disease resistance, drought tolerance, and yield potential. When choosing a variety, the personal experience of the survey respondents as well as the experience of their peers were identified as the most important sources of information. Our survey gives valuable insights into the challenges European potato farmers are facing in times of climate change. Supplying farmers with better-adapted varieties would be a well-targeted and well-accepted measure to advance climate change adaptation

Use of Novel Techniques in Plant Breeding and Practical Consequences Concerning Detection, Traceability, Labeling, and Risk Assessment

Genetically modified plants (GMP) are regulated by comprehensive EU legislation. Cisgenesis, intragenesis, oligo-directed mutagenesis (ODM), zinc-finger nucleases (ZFN), and agroinfiltration were examined concerning detection, traceability, labeling, and risk assessment. Similar transformation methods -- as in transgenesis using genetic elements from same or cross-compatible plant species -- characterize cisgenesis and intragenesis. Targeting the genome with ODM or ZFN minimizes unintended effects, but current data indicate limited efficiency and specificity; modifications are similar to those occurring during traditional plant breeding. The characteristics of plants produced by these techniques affect detection in the supply chains. Detection is possible when the target site is known, except for agroinfiltration that aims at transient expression of a gene/trait. The basis to assess potential risks arising from relevant plants and derived food and feed is similar to that of GMP. Depending on the specifics of the plant under investigation, data requirements for regulators may be reconsidered case-by-case