Application of a novel bioorganic fertilizer (BIO) has been effectively used to inhibit weeds in rice paddies. To identify changes in soil bacterial community and enzymes in response to BIO treatments, field experiments were carried out in five major rice-growing areas in China. The dominant phylogenetic groups recorded included Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria. Anaeromyxobacter, Bacteroides, Bifidobacterium, Escherichia- Shigella, Geobacter and Haliangium were significantly different between BIO-treatment and untreated control and aided in general function (R), amino acid transport, metabolism (E) and transcription (K) clusters. The soil chemical properties and enzyme activities were less affected by BIO at these study sites. RDA analysis showed that soil bacterial community had a significant positive correlations among northern latitude, eastern longitude, exchangeable K, total K, total P, soil pH, and total N, except for organic matter, hydrolytic N and extractable P. Overall, our work showed that application of BIO does not alter the main community structure and functional diversity of soil bacteria in rice paddies and should be encouraged for use as a sustainable weed management strategy.

Identification of new binding targets is essential for the development of herbicides and phytotoxin-tolerant crops. Caprylic acid (CAP) is a safe and non-selective bio-herbicide in uncultivated areas. However, the herbicidal action of CAP remains unclear. Herein, metabolomic and proteomic profiling indicated that a serine hydroxymethyl transferase in Conyza canadensis ( Cc SHMT1) is a promising candidate binding targeted for CAP. The protein abundance and activity of Cc SHMT1 were decreased in a time- and dosage-dependent manners after CAP treatment. CAP competes with phenyl-serine at the binding sites, decreasing the enzymatic activity of Cc SHMT1. Overexpression of CcSHMT1, AtSHMT1 and OsSHMT1 in Arabidopsis or rice endowed plants with high tolerance to CAP treatment, whereas the knockout of osshmt1 led to death of plants under normal atmospheric conditions. Furthermore, T194A, T194A/ M195V and D209N Osshmt1 mutant plants derived from base editing exhibited tolerance to CAP. CAP bound to Cc SHMT1 with high affinity, and Ala191 in the key domains of N-terminus was identified to be critical for the binding site of CAP. Collectively, our findings demonstrate that Cc SHMT1 is a binding target for herbicidal activity of CAP. This study marks a key step in the druggability of SHMT inhibitors and represents an attractive target for phytotoxin-tolerant crops.

Identification of new binding targets is essential for the development of herbicides and phytotoxin-tolerant crops. Caprylic acid (CAP) is a safe and non-selective bio-herbicide in uncultivated areas. However, the herbicidal action of CAP remains unclear. Herein, metabolomic and proteomic profiling indicated that a serine hydroxymethyl transferase in Conyza canadensis (CcSHMT1) is a promising candidate binding targeted for CAP. The protein abundance and activity of CcSHMT1 were decreased in a time- and dosage-dependent manners after CAP treatment. CAP competes with phenyl-serine at the binding sites, decreasing the enzymatic activity of CcSHMT1. Overexpression of CcSHMT1, AtSHMT1 and OsSHMT1 in Arabidopsis or rice endowed plants with high tolerance to CAP treatment, whereas the knockout of osshmt1 led to death of plants under normal atmospheric conditions. Furthermore, T194A, T194A/ M195V and D209N Osshmt1 mutant plants derived from base editing exhibited tolerance to CAP. CAP bound to CcSHMT1 with high affinity, and Ala191 in the key domains of N-terminus was identified to be critical for the binding site of CAP. Collectively, our findings demonstrate that CcSHMT1 is a binding target for herbicidal activity of CAP. This study marks a key step in the druggability of SHMT inhibitors and represents an attractive target for phytotoxin-tolerant crops.

Application of the novel bioorganic fertilizer (BIO) is effectively used to inhibit weeds in rice paddies. To identify changes in soil bacterial community and enzymes in response to BIO treatments, field experiments were carried out in five major rice-growing areas in China. The dominant phylogenetic groups recorded included Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria. Anaeromyxobacter, Bacteroides, Bifidobacterium, Escgerichia- Shigella, Geobacter and Haliangium were significantly different and aided in general function (R), amino acid transport, metabolism (E) and transcription (K) clusters between BIO-treatment and untreated control. The soil chemical properties and enzyme activities were less affected by BIO at these study sites. RDA analysis showed that soil bacterial community had a significant positive correlations among northern latitude, eastern longitude, exchangeable K, total K, total P, soil pH, and total N, except for organic matter, hydrolytic N and extractable P. Overall, our work showed that application of BIO does not alter the main community structure and functional diversity of soil bacterial in rice paddies and should be encouraged for use as a sustainable weed management strategy.