First Report of Round Leaf Spot on Sophora tonkinensis Caused by Didymella glomerata in China.

The root of Sophora tonkinensis Gagnep is an important medicinal material in China. An unknown foliar disease, first observed In July 2018, occurred over 240 ha of S. tonkinensis (totally cultured 600 ha) in Guangxi, China, in December 2019. The initial symptoms on leaf were seen as small, tawny spots (0.5 to 1.5 mm in diam.). As the disease progressed, the lesions enlarged into grayish and dark brown concentric rings (5 to 10.0 mm in diam.) resulting in black protuberances in the center of the spots. Severe infections would adversely affect plant growth, and cut the production by 30-40%. Symptomatic leaves were sampled and the surface was sterilized with 75% ethanol for 30 s and then soaked in 0.1% HgCl2 for 2 min. After three washes with sterile distilled water, the samples were dried, placed aseptically onto potato dextrose agar (PDA) plates, and incubated at 28°C. Three days later, the isolates were placed on new PDA medium for subsequent purification and sporulation. The fungus, SDG-1, was recovered from 85% of the total 40 isolates. Its colonies were whitish initially and then became olive green 7 days after incubation at 28 °C. The pycnidias were globose to subglobose, initially brown and darken at maturity, 85 to 300 × 70 to 280 µm in size. The conidia were colorless, single-celled, rounded to ellipsoidal and 3.5 to 6.6 × 1.5 to 3.8 µm. The chlamydospores were multicellular and brick trellised, usually forming branched or unbranched chains, light to dark brown in color and measured 28.5 to 44.5 × 8.2 to 16.5 µm. The morphological characteristics were consistent with Didymella glomerata. The rDNA-ITS, ß-tubulin and actin of strain SDG-1 were PCR amplified, and the DNA sequencing results were almost 100% identical to those of D. glomerata, respectively (GenBank database accession numbers MN 435377, MN447333 and MN447334, respectively). The multi-locus phylogenetic analysis was carried out with the obtained sequences, which revealed that the isolates clustered within D. glomerata with the similarity of 100% (Fig.3). Therefore, based on the morphology and phylogenetic tree, strain SDG-1 was identified as D. glomerata. For pathogenicity tests, the S. tonkinensis was cultured for two years, and the conidial suspension of SDG-1 (1 × 106 conidia /mL) was prepared by harvesting conidia from a 10-day-old culture on PDA. Conidia were sprayed onto the healthy leaves of S. tonkinensis for co-culture, while the control group was sprayed with sterile distilled water. Each experiment was performed three times. All plants were covered with plastic bags for 3 days in order to maintain high humidity and cultured in a greenhouse at 28 °C with a 12-h/12-h light/dark cycle. The symptoms appeared 7 days after the leaves were inoculated with spores, which were identical to those observed in the field. The pathogenic fungus was re-isolated from the infected leaves and identified as previously described. The control leaves remained symptomless during the pathogenicity tests. According to the previous literature, D. glomerata is a plant pathogenic fungus with a wide host range, which can damage up to 100 species of woody and herbaceous plants (Aghapour et al. 2009, Lahoz et al. 2007). To our knowledge, this is the first report of D. glomerata causing round leaf spot on S. tonkinensis in China.

Identification of novel and conserved microRNAs in Panax notoginseng roots by high-throughput sequencing.

BACKGROUND: MicroRNAs (miRNAs) are small, non-coding RNAs that are important regulators of gene expression, and play major roles in plant development and their response to the environment. Root extracts from Panax notoginseng contain triterpene saponins as their principal bioactive constituent, and demonstrate medicinal properties. To investigate the novel and conserved miRNAs in P. notoginseng, three small RNA libraries constructed from 1-, 2-, and 3-year-old roots in which root saponin levels vary underwent high-throughput sequencing. METHODS: P. notoginseng roots, purified from 1-, 2-, and 3-year-old roots, were extracted for RNA, respectively. Three small libraries were constructed and subjected to next generation sequencing. RESULTS: Sequencing of the three libraries generated 67,217,124 clean reads from P. notoginseng roots. A total of 316 conserved miRNAs (belonging to 67 miRNA families and one unclassified family) and 52 novel miRNAs were identified. MIR156 and MIR166 were the largest miRNA families, while miR156i and miR156g showed the highest abundance of miRNA species. Potential miRNA target genes were predicted and annotated using Cluster of Orthologous Groups, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes. Comparing these miRNAs between root samples revealed 33 that were differentially expressed between 2- and 1-year-old roots (8 increased, 25 decreased), 27 differentially expressed between 3- and 1-year-old roots (7 increased, 20 decreased), and 29 differentially expressed between 3- and 2-year-old roots (8 increased, 21 decreased). Two significantly differentially expressed miRNAs and four miRNAs predicted to target genes involved in the terpenoid backbone biosynthesis pathway were selected and validated by quantitative reverse transcription PCR. Furthermore, the expression patterns of these six miRNAs were analyzed in P. notoginseng roots, stems, and leaves at different developmental stages. CONCLUSIONS: This study identified a large number of P. notoginseng miRNAs and their target genes, functional annotations, and gene expression patterns. It provides the first known miRNA profiles of the P. notoginseng root development cycle.

[Study on exogenous hormones inducing parthenocarpy fruit growth and development and quality of Siraitia grosvenorii].

To explore the growth and development and analyze the quality of the parthenocarpy fruit induced by exogenous hormones of Siraitia grosvenorii. the horizontal and vertical diameter, volume of the fruit were respectively measured by morphological and the content of endogenous hormones were determined by ELISA. The size and seed and content of mogrosides of mature fruit were determined. The results showed that the fruit of parthenocarpy was seedless and its growth and development is similar to the diploid fruit by hand pollination and triploid fruit by hand pollination or hormones. But the absolute value of horizontal and vertical diameter, volume of parthenocarpy fruit was less than those of fruit by hand pollination, while triploid was opposite. The content of IAA, ABA and ratio of ABA/GA was obviously wavy. At 0-30 d the content of IAA and ABA of parthenocarpy fruit first reduced then increased, content of IAA and GA parthenocarpy fruit was higher than that of fruit by hand pollination. Mogrosides of parthenocarpy fruit was close to pollination fruit. Hormones can induce S. grosvenorii parthenocarpy to get seedless fruit and the fruit shape and size and quality is close to normal diploid fruit by hand pollination and better than triploid fruit by hormone or hand pollination.

[Effect of PP333 treatment on seed yield and root of Flemingia philippinensis].

OBJECTIVE: To study the effect of PP333 treatment on seed yield,medicinal materials yield and quality of Flemingia Philippinensis. METHODS: The experiment was in split plot design for PP333 in main plot and in planting density subplot. RESULTS: The seed yield of 600 mg/L (PP333) + 60 plants/m2 (planting density) was the highest. The medicinal materials yield of 600 mg/L (PP333) + 90 plants/m2 (planting density) was the highest. The quality of 900 mg/L( PP333) + 60 plants/m2 (planting density) was the best. CONCLUSION: The appropriate density of PP333 and planting can improve seed yield,medicinal materials yield and quality of Flemingia Philippinensis.

[Growth curve of Siraitia grosvenorii and correlative analysis of seed and growth of fruit].

OBJECTIVE: To establish the growth curve of Siraitia grosvenorii and analyze the correlation between seed and growth of fruit. METHOD: The growth curve fitting function was applied for the study of correlation between seed and fruit growth. RESULT: The significant positive correlation existed between seed and horizontal diameter x vertical diameter, not between seed and flesh weight of single fruit. CONCLUSION: The growth curve is a reciprocal function, and seed is one of major factors to influencing the size of fruits and the shape of fruit.

[Inspection on result of artemisinin content rank distribution in Guangxi].

OBJECTIVE: In order to enhance the yield of artemisinin, makes out the Artemisia annua adaptive area regional assignment in Guangxi. To ensure the nicety in study, on the base of literature study and experience on the spot, the article inspect the division result. METHOD: By document analysis and colleted data of A. annua, make out sample collect proceed and inspect the result of artemisinin content rank distribution in Guangxi. RESULT AND CONCLUSION: Result of A. annua regional assignment is checked out in the article, the result passes the check by AQL (32, 4). The conclusions insure subsequence study and the A. annua sample collect. The result of artemisinin content rank distribution in Guangxi can be used in artemisinin production.

[Evaluation on germplasm resources of main production area of Artemisia annua in China].

OBJECTIVE: To evaluate and select excellent germplasm resources of Artemisia annua L., providing basic data for data base and breeding of A. annua. METHOD: Seventy-two germplasms of A. annua, which were collected from main production areas, were planted in germplasm resources garden in Jingxi and Nanning under the same conditions. The samples were gathered in the squaring stage. Artemisinin was extracted by supersonic wave and determined by ultraviolet spectrophotometry. RESULT: The leaf's yield and the content of artemisinin in the samples of different germplasms were varied significantly. Effect of environment on artemisinin content was more than that of hereditary factors. The content of artemisinin was different when the same material of A. annua grew in different place. The content of artemisinin in next year's plant was decreasing. CONCLUSIONS: Seven germplasms from south of China have been selected, their content of artemisinin was above 0.9% and calculated yield was more than 2250 kg x hm(-2). The content of artemisinin has been affected by hereditary factors and variation of the growth environment.

[Study on quantitative assessment of Siraitia grosvenorii germplasms by general index].

OBJECTIVE: To establish a weight-marking method and evaluate Siraitia grosvenorii germplasms. METHOD: The characters of 21 kinds of S. grosvenorii germplasms in the field and the lab were analyzed, seven important characters were selected to weight the marks. A general evaluation index was made and used to evaluate S. grosvenorii germplasms. RESULT: The evaluation result of 21 kinds of S. grosvenorii germplasms by the weight-marking method was consistent with production practice. Meanwhile, the new variety Yongqing No. 1 and major cultivars were the superior germplasms. CONCLUSION: A rational technique system of evaluating S. grosvenorii germplasms was established, and the superior germplasms were selected.