Interference of Dihydrocoumarin with Hormone Transduction and Phenylpropanoid Biosynthesis Inhibits Barnyardgrass (Echinochloa crus-galli) Root Growth

Botanical compounds with herbicidal activity exhibit safety, low toxicity, and low chances of herbicide resistance development in plants. They have widespread applications in green agricultural production and the development of organic agriculture. In the present study, dihydrocoumarin showed potential as a botanical herbicide, and its phenotypic characteristics and mechanism of action were studied in barnyardgrass [Echinochloa crus-galli (L.) P.Beauv.] seedlings. The results indicated that dihydrocoumarin inhibited the growth of barnyardgrass without causing significant inhibition of rice seedling growth at concentrations ranging between 0.5 and 1.0 g/L. Additionally, dihydrocoumarin treatment could cause oxidative stress in barnyardgrass, disrupt the cell membrane, and reduce the root cell activity, resulting in root cell death. Transcriptomic analyses revealed that dihydrocoumarin could inhibit barnyardgrass normal growth by affecting the signal transduction of plant hormones. The results showed significant differential expression of plant hormone signal transduction genes in barnyardgrass. Additionally, dihydrocoumarin interfered with the expression of numerous phenylpropanoid biosynthesis genes in barnyardgrass that affect the production of various vital metabolites. We speculate that the barnyardgrass growth was suppressed by the interaction among hormones and phenylpropanoid biosynthesis genes, indicating that dihydrocoumarin can be applied as a bioherbicide to control barnyardgrass growth in rice transplanting fields

Proteomic Analysis Comparison on the Ecological Adaptability of Quinclorac-Resistant Echinochloa crus-galli

Barnyardgrass (Echinochloa crus-galli L.) is the most serious weed threatening rice production, and its effects are aggravated by resistance to the quinclorac herbicide in the Chinese rice fields. This study conducted a comparative proteomic characterization of the quinclorac-treated and non-treated resistant and susceptible E. crus-galli using isobaric tags for relative and absolute quantification (iTRAQ). The results indicated that the quinclorac-resistant E. crus-galli had weaker photosynthesis and a weaker capacity to mitigate abiotic stress, which suggested its lower environmental adaptability. Quinclorac treatment significantly increased the number and expression of the photosynthesis-related proteins in the resistant E. crus-galli and elevated its photosynthetic parameters, indicating a higher photosynthetic rate compared to those of the susceptible E. crus-galli. The improved adaptability of the resistant E. crus-galli to quinclorac stress could be attributed to the observed up-regulated expression of eight herbicide resistance-related proteins and the down-regulation of two proteins associated with abscisic acid biosynthesis. In addition, high photosynthetic parameters and low glutathione thiotransferase (GST) activity were observed in the quinclorac-resistant E. crus-galli compared with the susceptible biotype, which was consistent with the proteomic sequencing results. Overall, this study demonstrated that the resistant E. crus-galli enhanced its adaptability to quinclorac by improving the photosynthetic efficiency and GST activity

Proteomic Analysis Comparison on the Ecological Adaptability of Quinclorac-Resistant <i>Echinochloa crus-galli</i>

Barnyardgrass (Echinochloa crus-galli L.) is the most serious weed threatening rice production, and its effects are aggravated by resistance to the quinclorac herbicide in the Chinese rice fields. This study conducted a comparative proteomic characterization of the quinclorac-treated and non-treated resistant and susceptible E. crus-galli using isobaric tags for relative and absolute quantification (iTRAQ). The results indicated that the quinclorac-resistant E. crus-galli had weaker photosynthesis and a weaker capacity to mitigate abiotic stress, which suggested its lower environmental adaptability. Quinclorac treatment significantly increased the number and expression of the photosynthesis-related proteins in the resistant E. crus-galli and elevated its photosynthetic parameters, indicating a higher photosynthetic rate compared to those of the susceptible E. crus-galli. The improved adaptability of the resistant E. crus-galli to quinclorac stress could be attributed to the observed up-regulated expression of eight herbicide resistance-related proteins and the down-regulation of two proteins associated with abscisic acid biosynthesis. In addition, high photosynthetic parameters and low glutathione thiotransferase (GST) activity were observed in the quinclorac-resistant E. crus-galli compared with the susceptible biotype, which was consistent with the proteomic sequencing results. Overall, this study demonstrated that the resistant E. crus-galli enhanced its adaptability to quinclorac by improving the photosynthetic efficiency and GST activity

Effects of Salinity-Stress on Seed Germination and Growth Physiology of Quinclorac-Resistant <i>Echinochloa crus-galli</i> (L.) Beauv

With the expansion of saline-alkaline tolerant rice in China, the effects of salinity stress (NaCl) on quinclorac-resistant Echinochloa crus-galli (L.) Beauv (E. crus-galli) is unclear. In this study, the growth chamber experiment was conducted to test the germination and growth physiology of seven populations of E. crus-galli with quinclorac-different resistance levels which were collected from Hunan province. The results showed that a significant decrease of the germination rate and fresh weight of the plants, as well as the length of the roots and young shoots appeared, along with the increased resistance while treated with NaCl. However, no significant differences were detected between quinclorac-resistant and -susceptible E. crus-galli populations while without NaCl treatment. A further study with spectrophotometer showed that the salinity treatment resulted in the increase of the GST activity in all E. crus-galli populations, which are more obvious in those resistant biotypes, and transcriptomics revealed that salt stress reduces the adaptability of quinclorac-resistant E. crus-galli by reducing the biosynthesis, activities of antioxidant enzymes and metabolic enzyme. This study demonstrated that salinity stress (NaCl) may reduce the adaptability of quinclorac-resistant E. crus-galli

Effects of Salinity-Stress on Seed Germination and Growth Physiology of Quinclorac-Resistant Echinochloa crus-galli (L.) Beauv

With the expansion of saline-alkaline tolerant rice in China, the effects of salinity stress (NaCl) on quinclorac-resistant Echinochloa crus-galli (L.) Beauv (E. crus-galli) is unclear. In this study, the growth chamber experiment was conducted to test the germination and growth physiology of seven populations of E. crus-galli with quinclorac-different resistance levels which were collected from Hunan province. The results showed that a significant decrease of the germination rate and fresh weight of the plants, as well as the length of the roots and young shoots appeared, along with the increased resistance while treated with NaCl. However, no significant differences were detected between quinclorac-resistant and -susceptible E. crus-galli populations while without NaCl treatment. A further study with spectrophotometer showed that the salinity treatment resulted in the increase of the GST activity in all E. crus-galli populations, which are more obvious in those resistant biotypes, and transcriptomics revealed that salt stress reduces the adaptability of quinclorac-resistant E. crus-galli by reducing the biosynthesis, activities of antioxidant enzymes and metabolic enzyme. This study demonstrated that salinity stress (NaCl) may reduce the adaptability of quinclorac-resistant E. crus-galli