First Report of Leaf Black Spot Caused by Alternaria alternata on Rosemary (Rosmarinus officinalis L.) in China.

Rosemary (Rosmarinus officinalis L.) is an aromatic, evergreen, medicinally important shrub and widely used for cooking, tea, cosmetics as well as medicinal materials. It is grown in many countries including China that had more than 9300 hm2 of commercial cultivation area in 2021. In March 2020, a leaf spot disease sporadic occurred in field rosemarry plants in Nanyang City (32º51´ N, 111º36´ E), Henan Province, China. The disease outbreaked in September with a disease incidence of 57-83%. Symptoms initially appeared as small brown leaf spots that gradually expanded into dark blackbrown irregular lesions. Most of the spots started from the leaf tip or leaf margin, and gradually spread to the leaf base, resulting in heavy defoliation especially on rainy days. Diseased leaf segments (1×3 mm) were surface-sterilized by dipping in 1% sodium hypochlorite for 1 min, rinsed three times with sterile distilled water, and plated on potato dextrose agar, then incubated at 28°C in the dark for 5 days. Twelve fungal isolates with the same morphological characteristics were obtained from nine affected leaves. The fungal colonies were initially white and turned gray brown with flocculent aerial mycelia and a whorled back. Conidia were frequently born in a long chain, with a short beak, brown or light-brown, 13.2 to 48. 7 (average 26.1) × 4.0 to 13.1 (average 8.0) µm in size (n=148) with 0 to 8 transverse and 0 to 3 longitudinal/oblique septa. Phenotypic features of the isolates agreed with those of Alternaria alternata (Simmons et al. 2007). Two isolates Aa1 and Aa2 were randomly selected for molecular and pathogenicity tests. DNA was extracted from mycelia. Partial sequences of internal transcribed spacer (ITS) and translation elongation factor 1-alpha (TEF1-α) were amplified using the primer pairs ITS1/ITS4 and EFI-728F/EFI-986R (Wei et al. 2022), respectively. The GenBank accession nos. were OK036714 and OK036715 for ITS, and ON951980 and ON951981 for TEF1-α of Aa1 and Aa2, respectively, with a maximal identity of greater than 99% to multiple A. alternata strains. In the neighbour joining phylogenetic tree of the amplified ITS and TEF1-α sequences both Aa1 and Aa2 clustered with A. alternata strains, clearly separating them from other Alternaria spp. For pathogenicity test, conidial suspensions (1×106 spores /mL) of Aa1 and Aa2 were separately sprayed on healthy one-year-old rosemary plants (n=3) with their leaves slightly wounded with a sterilized needle. Control plants (n=3) were sprayed with sterile water. Both inoculated and control plants were incubated at 90% RH, 28 °C. After 14 days, all the inoculated leaves showed black brown lesions similar to those on naturally affected field plants, whereas controls remained symptomless. Fungal cultures with the same phenotypic features as the inocula were constantly re-isolated from the infected leaves. A. alternata was reported as pathogen causing foliar necrosis on rosemary in Italy (Perello et al.1995) and leaf spot (or leaf blight) on multiple plant species such as Actaea dahurica (Hai et al. 2022), and Ligustrum japonicum (Wei et al. 2022) in China. This is the first report of A. alternata causing leaf black spot on rosemary in China.

First Report of Soft Rot Caused by Aspergillus niger sensu lato on Mother-in-law's Tongue in China.

"Mother-in-law's tongue" (MLT) [Dracaena trifasciata (Prain) Mabb. (syn. Sansevieria trifasciata Prain.)], also known as "Saint George's sword", "snake plant", "tiger's tail orchid", etc., is an evergreen perennial ornamental plant grown worldwide. In September 2016, severe soft rot occurred on the leaves of MLT in a flower market in Nanyang city (32º56´N, 112º32´E), Henan province, China with 25% disease incidence (n=100). Water-soaked spots initially appeared on the leaf margin, enlarged rapidly, and became soft rot under excessively watered conditions. A blight zone was visualized at the margin of a developing lesion in backlit conditions. Severely affected leaves folded down from the lesions. Lesion expansion stopped under dry conditions. Grey or dark brown mycelia were frequently seen on the lesions. Tissue pieces (4×4 mm2) at the margin of lesions were cut out, treated with 75% ethanol for 10 s, followed by 70 s in 0.1% HgCl2, rinsed eight times with sterile water, and plated on potato dextrose agar (PDA) medium. Pure Aspergillus cultures were obtained from the surface-disinfected lesions after 4 days of incubation at 26°C. Two single-spore-derived isolates (An-1 and An-2) were randomly selected and used for morphological and molecular identifications as well as pathogenicity tests. The isolates formed round dark brown colonies with a large number of conidia after 5 days of incubation on PDA at 28°C. Conidia were subsphaeroidal or oblate, unicellular, dark brown, 2.9-4.2(3.5) × 1.9-3.4(2.7) µm in size (n=100), developed from a two-series of strigmata born on a conidial head, with ridge or stab-shaped prominences. For pathogenicity tests, the two isolates were separately grown on oatmeal agar and incubated at 30°C for 6 days. Mycelial plugs (5 mm diam.) were inoculated on the scalpel incision X-shaped wounds of surface-disinfected leaves of MLT. The inoculated leaves were kept on a two-layer of wet napkin in a steel basin covered with a plastic film. Soft rot symptoms developed from the wounds 6 days after incubation, similar to those observed on naturally affected leaves. The An-1- and An-2-inoculated unwounded leaves remained symptomless during the pathogenicity tests. Fungal cultures with the same phenotypes as the inocula were consistently reisolated from the lesions of the leaves inoculated by each of the two isolates, verifying the isolates as the causal agent of the disease based on Koch's postulates. Both ß-tubulin gene and rDNA-ITS (internal transcribed spacer) sequences of the two isolates were separately amplified and sequenced. Sequences were submitted to GenBank with accession numbers MN259522 and MN259523 for the ß-tubulin gene sequences, and accession numbers MN227322 and MN227324 for the rDNA-ITS sequences of An-1 and An-2, respectively. Both An-1 and An-2 were clustered with members of Aspergillus niger van Tieghem in the phylogenetic tree of rDNA-ITS, clearly separated from other Aspergillus spp. In the phylogenetic tree of ß-tublin gene, both An-1 and An-2 formed a subclade inside a large clade consisting of members of A. niger in strict sense. Based on the molecular and morphological results, both An-1 and An-2 clearly separated from other Aspergillus spp. and can be considered as A. niger sensu lato. Foliar diseases of MLT are known to be caused by a few fungal species such as Chaetomella spp. (Li et al. 2014) and Colletotrichum sansevieriae (Nakamura et al. 2006). This is the first report of A. niger sensu lato causing soft rot on MLT in China.

Effect of mechanically damaged starch from wheat flour on the quality of frozen dough and steamed bread.

The influence of damaged starch (DS) on the quality of frozen dough and steamed bread were investigated. Characterization of the farinographical properties showed that DS levels affected water absorption, development, weakness, falling number and gluten index. Flour viscosity profiles indicated that pasting temperatures increased, but peak viscosity, low viscosity, breakdown, final viscosity and setback increased and then decreased with increasing amounts of DS. Compared to leavened dough, unleavened dough had significantly higher peak times, of T21 and T22, and was also affected by DS concentration. Steamed bread had a higher specific volume, relatively lower hardness, exhibited more whiteness, and a higher degree of gumminess and chewiness with higher DS levels. We compared two methods of making steamed bread and assessed the quality of the product. We found that an appropriate DS content improved the quality of frozen dough and steamed bread. This study provides the basis for future development and improvements to methods for making frozen dough products.

Extraction, characterization and spontaneous emulsifying properties of pectin from sugar beet pulp.

The effects of organic acid extractants on the yield and characteristics of pectin from sugar beet pulp were investigated with citric acid, malic acid and lactic acid at different pH (1.5 and 2.0) and time (1 h and 2 h). The results demonstrated that the yields of pectins were directly correlated with the decrease of pH and reaction time, and the optimum yield of 17.2% was obtained at pH 1.5 and 2 h. Furthermore, the acid type also affected the physicochemical characteristics of pectin, especially on the esterification degree (42-71), galacturonic acid content (60.2-77.8%), emulsion activity (35.2-40.1%) and emulsion stability (62.1-79.4%), and a relatively single pectin mainly consisted of homogalacturonan could be obtained under a suitable reaction condition, which was an excellent crude material for the production of emulsion activity.

The effect of Helicobacter pylori infection on expression of macrophage migration inhibitory factor by T cells and macrophages in gastric mucosa.

BACKGROUND: Macrophage migration inhibitory factor (MIF) plays a pivotal role in inflammatory and immune-mediated diseases. However, its molecular function and role in gastrointestinal diseases has rarely been studied and thus warrants an in-depth investigation. This study was designed and conducted to determine MIF expression in Helicobacter pylori (H. pylori)-induced gastritis and the effect of H. pylori on MIF expression in monocytes in vitro. METHODS: Gastric specimens of 62 patients with chronic gastritis were obtained through endoscopic biopsies. Both gastric antrum and body were examined for histopathologic changes. Positive H. pylori was determined through rapid urease test and histopathological examination. A patient was classified as H. pylori positive if both tests showed positive results. The updated Sydney System was employed to assess the severity and activity of gastric inflammation. Double immunoassaying for MIF/T-cells (CD45RO) and MIF/macrophage (KP1), as well as in situ hybridization for the expression of MIF mRNA were used for the current analysis. THP-1, a monocyte cell line, was co-incubated with H. pylori strains (ATCC26695) and subsequently examined for the expression of MIF protein and mRNA by enzyme linked immunosorbent assay and retrospective transcription-polymerase chain reaction, respectively. RESULTS: Among 62 patients with chronic gastritis, significant increase in total T-cells, MIF+ T-cells, total macrophages, MIF+ macrophages and MIF mRNA+ cells was observed in 42 H. pylori positive patients compared to H. pylori negative patients. Moreover, the increase of the MIF mRNA+ cells was highly correlated with the severity of the disease (number of MIF mRNA+ cells/mm(2), mild: 2834 +/- 382, moderate: 3569 +/- 123, severe: 3881 +/- 118, P < 0.01). In vitro results showed that the expression of MIF protein and mRNA in monocytes was significantly increased after incubation with H. pylori strains. CONCLUSIONS: Overexpression of MIF is common in H. pylori-induced gastric inflammation, which suggests MIF may play an important role in the initiation and development of this disease.