Tanshinones are diterpenoid compounds that are used to treat cardiovascular diseases. As current extraction methods for tanshinones are inefficient, there is a pressing need to improve the production of these bioactive compounds to meet increasing demand. Overexpression of SmMDS (2-c-methyl-d-erythritol 2,4-cyclodiphosphate synthase, a tanshinone biosynthesis gene) in transgenic Salvia miltiorrhiza hairy roots significantly increased the tanshinone yield compared to the control, and total tanshinone content in SmMDS-overexpressing lines increased after elicitor treatment. Total tanshinones increased to 2.5, 2.3, and 3.2 mg/g DW (dry weight) following treatment with Ag+, YE (yeast extract), and MJ (methyl jasmonate), respectively, compared with the non-induced transgenic line (1.7 mg/g DW). Also, qRT-PCR analysis showed that the expression levels of two pathway genes was positively correlated with increased accumulation of tanshinone. Our study provides an effective strategy for increasing the content of tanshinones and other natural compounds using a combination of genetic engineering and elicitor treatment.

Glutathione peroxidases (GPXs) are important enzymes in the glutathione-ascorbate cycle for catalyzing the reduction of H₂O₂ or organic hydroperoxides to water. GPXs play an essential role in plant growth and development by participating in photosynthesis, respiration, and stress tolerance. Rhodiola crenulata is a popular traditional Chinese medicinal plant which displays an extreme energy of tolerance to harsh alpine climate. The GPXs gene family might provide R. crenulata for extensively tolerance to environment stimulus. In this study, five GPX genes were isolated from R. crenulata. The protein amino acid sequences were analyzed by bioinformation softwares with the results that RcGPXs gene sequences contained three conserve cysteine residues, and the subcellular location predication were in the chloroplast, endoplasmic reticulum, or cytoplasm. Five RcGPXs members presented spatial and temporal specific expression with higher levels in young and green organs. And the expression patterns of RcGPXs in response to stresses or plant hormones were investigated by quantitative real-time PCR. In addition, the putative interaction proteins of RcGPXs were obtained by yeast two-hybrid with the results that RcGPXs could physically interact with specific proteins of multiple pathways like transcription factor, calmodulin, thioredoxin, and abscisic acid signal pathway. These results showed the regulation mechanism of RcGPXs were complicated and they were necessary for R. crenulata to adapt to the treacherous weather in highland.

Weeds cause the largest yield loss in soybean production. The development of herbicide-resistant soybean germplasm is of great significance for weed control and yield improvement. In this study, we used the cytosine base editor (BE3) to develop novel herbicide-resistant soybean. We have successfully introduced base substitutions in GmAHAS3 and GmAHAS4 and obtained a heritable transgene-free soybean with homozygous P180S mutation in GmAHAS4. The GmAHAS4 P180S mutants have apparent resistance to chlorsulfuron, flucarbazone-sodium, and flumetsulam. In particular, the resistance to chlorsulfuron was more than 100 times that of with wild type TL-1. The agronomic performance of the GmAHAS4 P180S mutants showed no significant differences to TL-1 under natural growth conditions. In addition, we developed allele-specific PCR markers for the GmAHAS4 P180S mutants, which can easily discriminate homozygous, heterozygous mutants, and wild-type plants. This study demonstrates a feasible and effective way to generate herbicide-resistant soybean by using CRISPR/Cas9-mediated base editing.