No abstract

China feeds approximately 22% of the global population with only 7% of the global arable land because of its surprising success in intensive agriculture. This outstanding achievement is partially overshadowed by agriculture-related large-scale environmental pollution across the nation. To ensure nutrition security and environmental sustainability, China proposed the Green Food Strategy in the 1990s and set up a specialized management agency, the China Green Food Development Center, with a monitoring network for policy and standard creation, brand authorization, and product inspection. Following these 140 environmental and operational standards, 15,984 green food companies provided 36,345 kinds of products in 2019. The cultivation area and annual domestic sales (CNY 465.7 billion) of green food accounted for 8.2% of the total farmland area and 9.7% of the gross domestic product (GDP) from agriculture in China. Herein, we systemically reviewed the regulation, standards, and authorization system of green food and its current advances in China, and then outlined its environmental benefits, challenges, and probable strategies for future optimization and upscaling. The rapid development of the green food industry in China suggests an applicable triple-win strategy for protecting the environment, promoting agroeconomic development, and improving human nutrition and health in other developing countries or regions.

Carotenoid cleavage dioxygenases (CCDs) drive carotenoid catabolism to produce various apocarotenoids and immediate derivatives with particular developmental, ecological, and agricultural importance. How CCD genes evolved with species diversification and the resulting functional novelties in cereal crops have remained largely elusive. We constructed a unified four-clade phylogenetic tree of CCDs, revealing a previously unanchored basal clade CCD10. CCD10 underwent highly dynamic duplication or loss events, even in the grass family. Different from cleavage sites of CCD8 and ZAXINONE SYNTHASE (ZAS), maize (Zea mays) ZmCCD10a cleaved differentially structured carotenoids at 5, 6 (59, 6') and 9, 10 (9', 10') positions, generating C 8 (6-methyl-5-hepten-2-one) and C 13 (geranylacetone, a-ionone, and b-ionone) apocarotenoids in Escherichia coli. Localized in plastids, ZmCCD10a cleaved neoxanthin, violaxanthin, antheraxathin, lutein, zeaxanthin, and b-carotene in planta, corroborating functional divergence of ZmCCD10a and ZAS. ZmCCD10a expression was dramatically stimulated in maize and teosinte (Z. mays ssp. parviglumis, Z. mays ssp. huehuetenangensis, Zea luxurians, and Zea diploperennis) roots by phosphate (Pi) limitation. ZmCCD10a silencing favored phosphorus retention in the root and reduced phosphorus and biomass accumulation in the shoot under low Pi. Overexpression of ZmCCD10a in Arabidopsis (Arabidopsis thaliana) enhanced plant tolerance to Pi limitation by preferential phosphorus allocation to the shoot. Thus, ZmCCD10a encodes a unique CCD facilitating plant tolerance to Pi limitation. Additionally, ZmCCD10a silencing and overexpression led to coherent alterations in expression of PHOSPHATE STARVATION RESPONSE REGULATOR 1 (PHR1) and Pi transporters, and cis-regulation of ZmCCD10a expression by ZmPHR1;1 and ZmPHR1;2 implies a probable ZmCCD10a-involved regulatory pathway that adjusts Pi allocation.

In China, green food refers to a wide array of certified agricultural and processed edible commodities that are produced strictly following defined standard protocols and labelled with a specified “Green Food” logo. The demand for green labelled rice is rapidly growing due to its higher quality and adherence to safety standards compared to conventional rice. Therefore, the physicochemical and nutritional quality of green rice needs to be further investigated for consumers’ benefits. Using Daohuaxiang 2, one of the most famous types of green rice, we found that green rice was significantly superior to conventional rice in terms of thousand kernel weight, chalkiness, amylose content, and rheological properties. Green rice contained lower levels of heavy metals than conventional rice due to a dramatic reduction in chemical inputs during its cultivation. The concentrations of Cr, As, Cd, Pb in green rice decreased, respectively, from 98.7 to 180.1 μg/kg, 49.8 to 62.3 μg/kg, 7.8 to 9.1 μg/kg, and 29.0 to 42.8 μg/kg on average. Gas chromatography coupled with mass spectrometry (GC–MS)-based metabolomics, in combination with multivariate analysis, revealed that 15 metabolites differentially accumulated when comparing green and conventional rice. Among these, 12 metabolites showed a high accumulation in green rice, including seven amino acids, two sugars, and three fatty acids. Overall, our results suggest the superior quality of a type of green rice that is popular in China, which may boost green rice consumption and facilitate the further expansion of green rice production in China.