[Status and further development of regulation for pesticide registration for Chinese medicinal materials].

Nowadays, the cultivation of traditional Chinese medicinal materials is faced with the problems of pesticides illegal uses and pesticides residues. In the early period of eco-agriculture of Chinese materia medica, the uses of pesticides in special time is still inevitable. However, the registration of pesticides for Chinese medicinal materials now is far from enough to meet demand. So it is necessary to publish policies to expand the pesticides registration for Chinese medicinal materials. We collected and analyzed the data of pesticide registration for Chinese medicinal materials, the results showed that till March 2018, there were 10 kinds of Chinese medicinal materials, 91 pesticide products and 46 kinds of pesticide ingredients registered. Based on the current status of the pesticide management in China and the experience of the registration pesticide for minor crops in countries around the world, we point out that the pesticide registration for Chinese medicinal materials should be carried out in the form of minor crops and some specific methods are also provided in this paper.

Six undescribed guaianolide-type sesquiterpenes from the aerial parts of Daphne penicillata.

Six undescribed guaianolide sesquiterpenes (1-6) were obtained from the aerial parts of Daphne penicillata. Their structures and absolute configuration were elucidated by HRESIMS, NMR analyses, ECD calculations and single-crystal X-ray diffraction analysis. Structurally, all compounds possess the typical 5,7-fused system of 8,12-guaianolides and this guaianolide-type was first reported to be isolated from Daphne penicillata. All compounds (1-6) were evaluated for anti-inflammatory and cytotoxic activity. Among them, compounds 1 and 5 showed moderate inhibitory effects on LPS-induced NO production in BV2 cells and 4 displayed potential inhibition against Hep3B cells with an IC50 value of 7.33 µM.

Structurally diverse rearranged sesquiterpenoids, including a pair of rare tautomers, from the aerial parts of Daphne penicillata.

Eight structurally diverse rearranged sesquiterpenoids, including seven undescribed sesquiterpenoids (1a/1b and 3-8) were obtained from the aerial parts of Daphne penicillata. 1a/1b, 3, 5 and 6 possess rare rearranged guaiane skeletons and 4 represents the first example of rearranged carotene sesquiterpenoids. Their structures and absolute configurations were determined by extensive spectroscopic analyses, NMR and ECD calculations. Interestingly, 1a and 1b were a pair of magical interconverting epimers that may interconvert by retro-aldol condensation. The mechanism of interconversion has been demonstrated indirectly by 9-OH derivatization of 1a/1b and a hypothetical biogenetic pathway was proposed. All compounds were evaluated for anti-inflammatory and cytotoxic activities. Among them, 1a/1b and 2 exhibited potential inhibitory activities on the production of NO against LPS-induced BV2 microglial cells.

Complete genome sequence of "Candidatus Phytoplasma sacchari" obtained using a filter-based DNA enrichment method and Nanopore sequencing.

Phytoplasmas are phloem-limited plant pathogens, such as sugarcane white leaf (SCWL) phytoplasma, which are responsible for heavy economic losses to the sugarcane industry. Characterization of phytoplasmas has been limited because they cannot be cultured in vitro. However, with the advent of genome sequencing, different aspects of phytoplasmas are being investigated. In this study, we developed a DNA enrichment method for sugarcane white leaf (SCWL) phytoplasma, evaluated the effect of DNA enrichment via Illumina sequencing technologies, and utilized Illumina and Nanopore sequencing technologies to obtain the complete genome sequence of the "Candidatus Phytoplasma sacchari" isolate SCWL1 that is associated with sugarcane white leaf in China. Illumina sequencing analysis elucidated that only 1.21% of the sequencing reads from total leaf DNA were mapped to the SCWL1 genome, whereas 40.97% of the sequencing reads from the enriched DNA were mapped to the SCWL1 genome. The genome of isolate SCWL1 consists of a 538,951 bp and 2976 bp long circular chromosome and plasmid, respectively. We identified 459 protein-encoding genes, 2 complete 5S-23S-16S rRNA gene operons, 27 tRNA genes, and an incomplete potential mobile unit (PMU) in the circular chromosome. Phylogenetic analyses and average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values based on the sequenced genome revealed that SCWL phytoplasma and sugarcane grassy shoot (SCGS) phytoplasma belonged to the same phytoplasma species. This study provides a genomic DNA enrichment method for phytoplasma sequencing. Moreover, we report the first complete genome of a "Ca. Phytoplasma sacchari" isolate, thus contributing to future studies on the evolutionary relationships and pathogenic mechanisms of "Ca. Phytoplasma sacchari" isolates.

2,3-Butanediol from the leachates of pine needles induces the resistance of Panax notoginseng to the leaf pathogen Alternaria panax.

Compared with the use of monocultures in the field, cultivation of medicinal herbs in forests is an effective strategy to alleviate disease. Chemical interactions between herbs and trees play an important role in disease suppression in forests. We evaluated the ability of leachates from needles of Pinus armandii to induce resistance in Panax notoginseng leaves, identified the components via gas chromatography-mass spectrometry (GC-MS), and then deciphered the mechanism of 2,3-Butanediol as the main component in the leachates responsible for resistance induction via RNA sequencing (RNA-seq). Prespraying leachates and 2,3-Butanediol onto leaves could induce the resistance of P. notoginseng to Alternaria panax. The RNA-seq results showed that prespraying 2,3-Butanediol onto leaves with or without A. panax infection upregulated the expression of large number of genes, many of which are involved in transcription factor activity and the mitogen-activated protein kinase (MAPK) signaling pathway. Specifically, 2,3-Butanediol spraying resulted in jasmonic acid (JA) -mediated induced systemic resistance (ISR) by activating MYC2 and ERF1. Moreover, 2,3-Butanediol induced systemic acquired resistance (SAR) by upregulating pattern-triggered immunity (PTI)- and effector-triggered immunity (ETI)-related genes and activated camalexin biosynthesis through activation of WRKY33. Overall, 2,3-Butanediol from the leachates of pine needles could activate the resistance of P. notoginseng to leaf disease infection through ISR, SAR and camalexin biosynthesis. Thus, 2,3-Butanediol is worth developing as a chemical inducer for agricultural production.

[Modification of quicklime on acid soil under forest and their effect on the growth of Panax notoginseng]. / ç”ŸçŸ³ç°å¯¹æž—ä¸‹é ¸åŒ–åœŸå£¤çš„è°ƒæŽ§ä½œç”¨åŠä¸‰ä¸ƒç”Ÿé•¿çš„å½±å“.

Soil acidification is an important factor leading to poor growth and root rot disease of Panax notoginseng in the understorey of forests. In this study, different amounts of quicklime (0, 500, 1000, 1500 and 2000 kg·hm-2) were amended into acid soil under forest. We evaluated the effect of quikelime addition on soil chemical properties, phenols, rhizosphere microorganisms and growth of P. notoginseng. The results showed that an appro-priate amount of quicklime addition (500-1000 kg·hm-2) could significantly increase soil pH, decrease the content of phenols (p-hydroxybenzoic acid, vanillin, syringic acid, ferulic acid and vanillic acid), promote P. notoginseng growth, and reduce the incidence of root rot disease. An appropriate amount of quicklime (500-1000 kg·hm-2) could significantly reduce the fungi:bacteria ratio, increase bacteria diversity, and increase the relative abundance of Ascomycota and Proteobacteria as well as Massilia and Sphingomonas. However, excessive quicklime addition (1500-2000 kg·hm-2) could reduce the content of available nitrogen and organic matter, and inhibit P. notoginseng growth. Therefore, 500-1000 kg·hm-2 of quicklime amendment could improve the chemical properties and microbial community of acid soil under forest, thereby promoting P. notoginseng growth, and reducing the incidence of root rot disease.

Appropriate nitrogen application enhances saponin synthesis and growth mediated by optimizing root nutrient uptake ability.

BACKGROUND: Cultivation of medicinal crops, which synthesize hundreds of substances for curative functions, was focused on the synthesis of secondary metabolites rather than biomass accumulation. Nutrition is an important restrict factor for plant growth and secondary metabolites, but little attention has been given to the plasticity of nutrient uptake and secondary metabolites synthesis response to soil nitrogen (N) change. METHODS: Two year-field experiments of Sanqi (Panax notoginseng), which can synthesize a high level of saponin in cells, were conducted to study the effects of N application on the temporal dynamics of biomass, nutrient absorption, root architecture and the relationships between these parameters and saponin synthesis. RESULTS: Increasing N fertilizer rates could improve the dry matter yields and nutrient absorption ability through increasing the maximum daily growth (or nutrient uptake) rate. Under suitable N level (225 kg/ha N), Sanqi restricted the root length and surface and enhanced the root diameter and N uptake rate per root length (NURI) to promote nutrient absorption, but the opposite status of Sanqi root architecture and NURI was found when soil N was deficient. Furthermore, increasing N rates could promote the accumulation of saponin in roots through improving the NURI, which showed a significant positive relationship with the content of saponin in the taproots. CONCLUSION: Appropriate N fertilizer rates could optimize both root architecture and nutrient uptake efficiency, then promote both the accumulation of dry matter and the synthesis of saponins.

[Isolation and identification of root endophytic and rhizosphere bacteria of rice landraces in Yuanyang Terrace, China].

ABSTRACT: To reveal root endophytic and rhizosphere bacteria constitution of rice landraces in Yuanyang Terrace, isolation was carried out by tissue isolation method and soil dilution plate method for two landraces of Yuelianggu and Hongjiaolaojing. A total of 399 bacterial strains isolated were identified by morphological characteristics, physiological and biochemical identification. The results showed that there were 8 genera isolated from the root of Yuelianggu and 5 genera from its rhizosphere soil, and 5 genera were same. For Hongjiaolaojing, there were 10 genera isolated from its root and 7 genera from its rhizosphere soil, and 6 genera were same. By molecular biology, identification, a total of 11 species and 5 genera were isolated from the root of Yuelianggu, 8 species and 4 genera from its rhizosphere soil, and 5 species and 4 genera were same. As for Hongjiaolaojing, there were 9 species and 5 genera isolated from its root, and 10 species and 3 genera from its rhizosphere soil, and 4 species and 2 genera were same. The results of physiological and biochemical characteristics identification method and molecular identification method were basically same at the genus level, while most of the strains could be identified to species by molecular identification. There were certain species homology and specificity in the root endophytic and rhizosphere bacteria of Yuanyang rice landraces.

Genetic analysis of rice varietal diversity for rice blast control.

Two Indica hybrid rice of Shanyou63 (A) and Shanyou22 (B), two glutinous landraces of Huanghenuo (C) and Zinuo (D) and three improved Japonica rice of Hexi41 (E), Chujing12 (F) and 8126 (G) were selected and their genetic resistance relationship was estimated using resistance gene analogue (RGA). The results showed that there were similar genetic relationships between hybrid varieties at the genetic similarity (GS) of 0.86,and among improved Japonica varieties at the GS of 0.84, while highly genetic diversifications between traditional varieties, Indica and Japonica varieties, traditional and modern variety ( GS:0.45). The results also showed that clustering analysis based on RGA data were generally corresponded to known pedigrees and blast field resistances of the varieties. Based on varietal differences in RGA data and agronomic traits, plot experiments of five mixed-planting combinations of A/C, A/D, B/C, B/D and A/B and two combinations of E/C and E/F/G were conducted in Jianshui and Shiping counties ( Indica rice growing region) and Luxi County (warm Japonica region) in Yunnan Province in past two years, respectively. The results demonstrated that rice blast management was more effective in five mixed-planting combinations of varieties with different genetic backgrounds (GS: 0.45-0.77) than in two combinations with similar genetic relationships (GS: 0.84-0.90), compared with their monocultures. It is evident for the highly susceptible landraces in mixed-planting to achieve disease control, with significant decreases both in incidence and severity. The blast control efficiencies of landraces in different mixture combinations reached to 54.47%-92.18%. The control efficiencies of improved varieties varied from 15.12% to 25.54% in mixture combinations with closed genetic relationship. In addition,the total yield of 5 varietal combinations with distant genetic relationship increased 539.0-904.0 kg/ha in the mixed-planting plots, at increase rates of 5.6%-10.2%. Mixed rice varieties with similar genetic background did not achieve significant yield increase. Otherwise, the yield of E/F/G decreased 2.7%-4.0% compared with pure stand. The results can provide scientific basis of varietal combinations in diversification experiments for blast control.