The call for agri-food system transformation is urgent in many global development agendas (UN 2023).  Food systems have contributed to economic prosperity and feeding the world, but they are also associated with numerous challenges, including climate change, continued hunger, poor diets and malnutrition, and increasing disparities (Webb et al. 2020; Fanzo et al. 2021).  The vulnerabilities of food systems have been further aggravated by the COVID-19 pandemic, geopolitical disruptions, extreme weather events, and economic uncertainties (IPCC 2023; FAO 2023).  The rapid population growth, urbanization and industrialization have also resulted in significant land and water resource pressures, as well as food safety and security in many developing countries.

Thus, the agri-food systems transformation should shift from addressing singular dimension (e.g., grain supply or grain self-sufficiency) to achieving multiple goals simultaneously, including nutrition, health, inclusion, environmental sustainability and climate change (Fan et al. 2021). 

There are several strategies that can be used for achieving these multiple goals including access to modern technologies such as internet, changing production structure, promoting more stable and resilient income for farmers, implementing social programs to protect vulnerable population, and of course continued technological and productivity improvement .

Under this context, this special focus of the Journal of Integrative Agriculture is to provide empirical evidence on multiple win strategies to achieve agri-food systems transformation.  The issue comprises nine papers covering a wide array of topics aimed at improved nutrition, sustainability inclusion and continued efficiency or productivity improvement within the food system.  We trust that these papers will enhance readers’ comprehension of how food system transformation can contribute to multiple dimensions of the food system’s goals.

Using scanner data on the consumption of packaged liquid beverages by Chinese urban households, we estimated the price elasticity of various beverages and compared the effects of volume-based versus sugar-content-based taxation strategies on consumer welfare.  Compared to the volume-based tax, the sugar-content-based beverage tax was predicted to cost less in compensating variation under the same amount of sugar reduced, indicating that taxation based on sugar content may be more efficient in preserving consumer welfare.  Further comparison across different socioeconomic groups reveals that, given current beverage consumption status in China, the efficiency advantage of the sugar-content-based taxation strategy is more pronounced than that of the volume-based taxation.  Our conclusions can provide insights for the food industry and the government to reduce the sugar content in beverages.

Ketosis, a common metabolic disease during early lactation, is associated with high circulating levels of β-hydroxybutyrate (BHB). A portion of BHB that reaches the mammary gland is utilized as precursor for synthesis of fatty acids. Recent findings from nonruminant studies revealed that long chain fatty acyl-CoA ligase 4 (ACSL4) could play a role in the regulation of cellular fatty acid metabolism, but the mechanisms by which ACSL4 mediates cellular lipid metabolism in response to BHB remains unclear. To achieve the aims, we conducted in vivo or in vitro analyses using bovine mammary gland biopsies and the immortalized mammary epithelial cell line (MAC-T). The in vivo study (n = 6 cows group^-1) involved healthy cows (plasma BHB < 0.60 mmol L^-1) or ketotic cows (plasma BHB > 2.0 mmol L^-1) from which mammary gland tissue was biopsied. In vitro, MAC-T cells were challenged with 0, 0.3, 0.6, 1.2, or 2.4 mmol L^-1 BHB for 24 h to determine an optimal dose. Subsequently, MAC-T were incubated with 1.2 mmol L^-1 BHB for 0, 3, 6, 12, 24, or 48 h. Furthermore, MAC-T cells were treated with small interfering ACSL4 (siACSL4) for 24 h or ACSL4 overexpression plasmid (pcACSL4) for 36 h followed by a challenge with 1.2 mmol L^-1 BHB for 24 h. Results showed that increased mRNA and protein abundance of lipogenic genes were linked to both mammary gland and in vitro challenge with BHB. BHB increased fatty acid content by activating ACSL4 expression, whereas inhibition of ACSL4 reduced BHB-induced reactive oxygen species (ROS) overproduction, enhancement of mitochondrial membrane potential, increase in fatty acid content, and lipid droplet accumulation. Furthermore, we also elevated ACSL4 expression with an overexpression plasmid to clarify its molecular role in response to BHB challenge. ACSL4 overexpression enhances BHB-induced lipid droplet accumulation by increased fatty acid content. Overall, the information showed that ACSL4 is crucial for the process of producing fatty acids from exogenous BHB. Reduced ACSL4 decreased fatty acid content and lipid droplet accumulation, improved mitochondrial function, directed more fatty acids towards oxidation. Thus, ACSL4 plays an important role in determining the fate of intracellular fatty acids and BHB in BMECs.

To evaluate the impact of climate change on maize production, it is critical to accurately measure the radiation use efficiency (RUE) for maize. In this study, we focused on three maize cultivars in Jilin Province, China: Zhengdan 958 (ZD958), Xianyu 335 (XY335), and Liangyu 99 (LY99).  Under the optimal growing conditions for high density (9 plants m^-2), we investigated the maize RUE during the vegetative and reproductive phases, and the entire growth period.  The results showed that the canopy light interception for maize peaked during anthesis.  After anthesis, maize plant biomass continued to accumulate.  Based on the absorbed photosynthetically active radiation (APAR), we calculated maize RUE.  During the entire growth period, maize RUE averaged 5.71 g MJ^-1 APAR among the three cultivars, with a high-to-low order of ZD958 (5.85 g MJ^-1 APAR)>XY335 (5.64 g MJ^-1 APAR)>LY99 (5.07 g MJ^-1 APAR).  Within the vegetative and reproductive growth periods, maize RUE averaged 6.85 and 5.64 g MJ^-1 APAR, respectively.  When utilizing maize models, such as APSIM, that depend on radiation use efficiency (RUE) to predict aboveground biomass accumulation, we observed that the current RUE value of 3.6 g MJ^-1 APAR is considerably lower than the measured value obtained under high-density optimal growing conditions.  Consequently, to derive the optimal potential yield for maize in such planting conditions, we recommend adjusting the RUE to a range of 5.07-5.85 g MJ^-1 APAR.