Scientific interest in pollution from antibiotics in animal husbandry has increased during recent years. However, there have been few studies on the vertical exposure characteristics of typical veterinary antibiotics in different exposure matrices from different livestock farms. This study explores the distribution and migration of antibiotics from feed to manure, from manure to soil, and from soil to vegetables, by investigating the exposure level of typical antibiotics in feed, manure, soil, vegetables, water, fish, and pork in livestock farms. A screening environmental risk assessment was conducted to identify the hazardous potential of veterinary antibiotics from livestock farms in southeast China. The results show that adding antibiotics to drinking water as well as the excessive use of antibiotic feed additives may become the major source of antibiotics pollution in livestock farms. Physical and chemical properties significantly affect the distribution and migration of various antibiotics from manure to soil and from soil to plant. Simple migration models can predict the accumulation of antibiotics in soil and plants. The environmental risk assessment results show that more attention should be paid to the terrestrial eco-risk of sulfadiazine, sulfamethazine, sulfamethoxazole, tetracycline, oxytetracycline, chlorotetracycline, ciprofloxacin, and enrofloxacin, and to the aquatic eco-risk of chlorotetracycline, ciprofloxacin, and enrofloxacin. This is the first systematic analysis of the vertical pollution characteristics of typical veterinary antibiotics in livestock farms in southeast China. It also identifies the ecological and human health risk of veterinary antibiotics.

The discovery and application of genome editing introduce a new era of plant breeding, giving researchers efficient tools for the precise engineering of crop genomes 1 . Here, we demonstrate the power of genome editing for engineering broad-spectrum disease resistance in rice (Oryza sativa). We first isolated a lesion mimic mutant (LMM) from a mutagenized rice population, demonstrated that a 29-bp deletion in a gene we named RESISTANCE TO BLAST1 (RBL1) caused this phenotype and showed that this mutation caused a ca. 20-fold reduction in yield. RBL1encodes a cytidine diphosphate diacylglycerol (CDP-DAG) synthase required for phospholipid biosynthesis 2 . Mutation of RBL1 results in reduced levels of phosphatidylinositol (PI) and its derivative PI(4,5)P2. Rice PI(4,5)P2 is enriched in cellular structures specifically associated with effector secretion and fungal infection, suggesting a role as a disease susceptibility factor 3 . Using targeted mutagenesis, we obtained an allele of RBL1, named RBL12, which confers broad-spectrum resistance but does not decrease yield in a model rice variety as assessed in small-scale field trials. Our study has demonstrated the usefulness of editing of an LMM gene, a strategy relevant to diverse LMM genes and crops. Main textGenome editing has been widely used in functional studies of genes but its potential for crop improvement has not yet been broadly utilized 4 . Plant diseases cause severe losses in agriculture, threatening global food security 5 . Rice blast alone, caused by the fungal pathogen Magnaporthe oryzae, results in annual yield losses that are sufficient to feed more than 60 million people worldwide 6 . Given this cost, cultivating crops with resistance to diseases, particularly broad-spectrum resistance, is highly desirable 7 . Despite the importance of this goal, only a limited number of broad-spectrum resistance genes have been cloned and used in the field, such as rice Xa21 (ref. 8 ), bsr-d1 (ref. 9 ), Pigm 10 , IPA1 (ref. 11 ), ROD1 (ref. 12 ), UMP1 (ref. 13 ), wheat Lr34 (ref. 14 ) and PsIPK1 (ref. 15 ), and barley mlo 16,17 .LMMs form hypersensitive response-like lesions (a form of programmed cell death) in the absence of pathogens 18 . LMMs often confer durable and broad-spectrum resistance, representing a potential source for breeding resistance to diseases. However, LMMs are usually associated with reduced yield, and therefore the use of the genes conferring LMM phenotypes (hereafter referred to as LMM genes) has not been fully exploited in plant breeding due to the lack of useful alleles.Phospholipids are essential components of biological membranes and are involved in various biological processes, including development and response to biotic and abiotic stress 19 . In phospholipid biosynthesis (Extended Data Fig. 1), phosphatidic acid (PA) and cytidine triphosphate (CTP) are converted to CDP-DAG by CDP-DAG synthases (CDSs). CDP-DAG and Myo-inositol are used to produce PI by phosphatidylinositol synthases (PISs) 20 . PI is added to by a varied number of p...

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