Towards the high-quality development of City Region Food Systems: Emerging approaches in China.

The outbreak of COVID-19 has underscored the vulnerability of our current food systems. In China, following a series of strategies in guaranteeing food security in the past decades, the pandemic has further highlighted the necessity to strengthen urban-rural linkages and facilitate the sustainable development of local agri-food systems. The study for the first time introduced the City Region Food Systems (CRFS) approach to Chinese cities and attempted to holistically structure, analyze and promote the sustainability of local food systems in China. Taking Chengdu as an example, the study first took stock of existing concepts and policies in China and the city, and defined the high-quality development goals of CRFS for Chengdu. An indicator framework was then developed to serve as a CRFS assessment tool for identifying existing challenges and potentials of local food systems. Further, a rapid CRFS scan using the framework was conducted in Chengdu Metropolitan Area, providing concrete evidence for potential policy interventions and practice improvement in the area. The study has explored new paradigm of analysis for food related issues in China and provided supporting tools for evidence-based food planning in cities, which collectively contribute to the food system transformation in a post-pandemic scenario.

Maize Plant Architecture Is Regulated by the Ethylene Biosynthetic Gene ZmACS7.

Plant height and leaf angle are two crucial determinants of plant architecture in maize (Zea mays) and are closely related to lodging resistance and canopy photosynthesis at high planting density. These two traits are primarily regulated by several phytohormones. However, the mechanism of ethylene in regulating plant architecture in maize, especially plant height and leaf angle, is unclear. Here, we characterized a maize mutant, Semidwarf3 (Sdw3), which exhibits shorter stature and larger leaf angle than the wild type. Histological analysis showed that inhibition of longitudinal cell elongation in the internode and promotion in the auricle were mainly responsible for reduced plant height and enlarged leaf angle in the Sdw3 mutant. Through positional cloning, we identified a transposon insertion in the candidate gene ZmACS7, encoding 1-aminocyclopropane-1-carboxylic acid (ACC) Synthase 7 in ethylene biosynthesis of maize. The transposon alters the C terminus of ZmACS7. Transgenic analysis confirmed that the mutant ZmACS7 gene confers the phenotypes of the Sdw3 mutant. Enzyme activity and protein degradation assays indicated that the altered C terminus of ZmACS7 in the Sdw3 mutant increases this protein's stability but does not affect its catalytic activity. The ACC and ethylene contents are dramatically elevated in the Sdw3 mutant, leading to reduced plant height and increased leaf angle. In addition, we demonstrated that ZmACS7 plays crucial roles in root development, flowering time, and leaf number, indicating that ZmACS7 is an important gene with pleiotropic effects during maize growth and development.

Local food systems and COVID-19: an insight from China.

•Effective governance and efficient coordination across multi-levels and multi-sectors are pivotal factors to ensure food supply during COVID-19.•Digital tools and innovative models provided valuable solutions to cope with the crisis in China, which can be further developed and contribute to the "New Normal".•The pandemic implies the necessity to strengthen urban-rural linkages and foster local food production for more resilient local food systems.