First Report of Root rot Caused by Mucor circinelloides on Fructus forsythiae in Hubei，China.

Fructus forsythiae is a typical traditional Chinese medicinal herb with antibacterial and anti-inflammatory effects. Surveys for root rot of F. forsythiae were conducted from 2021 to 2022 in China's major planting areas (Daweiyuan Village, Sanguandong Forest Area, Yunxi County, Shiyan City, Hubei Province, 32°52'52"N, 110°19'29"E). The disease has occurred in several plantations. A total of 200 F. forsythiae were investigated, among which 112 were diseased, the incidence rate was more than 50%, and all the plants in the plantation were over 3 years old. The roots of diseased plants were fully covered by white mycelia. When the disease was severe, leaves curled and fell, roots withered, and some eventually died. A total of 22 isolates were isolated from the 18 infected tissues of F. forsythiae and purified by single spore cultures on PDA medium. The 22 isolates similared in morphology to isolate Lianmao (The name is one of the five sequenced samples in the lab) were selected to be representative of the group. The results showed that these samples belonged to the same pathogen. The isolates were characterized by yellowish colonies composed of tall and short sporangiophores 6 to 11 µm in width, terminal and globose sporangia, ellipsoidal sporangiospores with dimensions of 5 to 8 µm in length and 4 to 5 µm in width, and obovoid columellae. It was identified as Mucor circinelloides, based on morphological characteristics (Schipper 1976). The ITS and LSU sequences of the fungus were amplified, and sequenced with the primers ITS1/ITS4 and LROR/LR5 (White et al. 1990; Rehner et al. 1994). Sequences from isolate Lianmao were deposited in GenBank (accession nos. OQ359158 for ITS, OQ359157 for LSU). Analysis using the BLAST algorithm of the two amplified sequences showed 99.69 to 100% similarity with the sequences (KY933391 and MH868051) of M. circinelloides. The isolated M. circinelloides was prepared into 150ml spore suspension (The method was to filter the PDB after 10 days of culture using gauze to get spore suspension. Then the concentration of spore suspension was diluted to 1.0×106 spores/ml using sterile water). The spore suspension was subsequently inoculated into healthy potted F. forsythiae plants. Uninoculated potted F. forsythiae plants served as controls. All the potted F. forsythiae plants were incubated at 25°C under 12h light and 12h dark conditions. The symptoms of the infected plants were similar to those observed in the field; The control plants were symptomless. The pathogen reisolated from symptomatic roots and morphologically identified as M. circinelloides. M. circinelloides has been reported as a pathogen of Morinda citrifolia, Aconitum carmichaelii and so on (Cui et al. 2021; Nishijima et al. 2011), but it has never been reported on F. forsythiae before. This is the first report of root rot caused by M.circinelloides on F. forsythiae. This pathogen may present a threat to the production of F. forsythiae in China.

Characterization of a novel wheat NAC transcription factor gene involved in defense response against stripe rust pathogen infection and abiotic stresses.

Proteins encoded by the NAC gene family constitute one of the largest plant-specific transcription factors, which have been identified to play many important roles in both abiotic and biotic stress adaptation, as well as in plant development regulation. In the current paper, a full-length cDNA sequence of a novel wheat NAC gene, designated as TaNAC4, was isolated using in silico cloning and the reverse transcription PCR (RT-PCR) methods. TaNAC4 sharing high homology with rice OsNAC4 gene was predicted to encode a protein of 308 amino acid residues, which contained a plant-specific NAC domain in the N-terminus. Transient expression analysis indicated that the deduced TaNAC4 protein was localized in the nucleus of onion epidemical cells. Yeast one-hybrid assay revealed that the C-terminal region of the TaNAC4 protein had transcriptional activity. The expression of TaNAC4 was largely higher in the wheat seedling roots, than that in leaves and stems. TaNAC4 transcript in wheat leaves was induced by the infection of strip rust pathogen, and also by exogenous applied methyl jasmonate (MeJA), ABA and ethylene. However, salicylic acid (SA) had no obvious effect on TaNAC4 expression. Environmental stimuli, including high salinity, wounding, and low-temperature also induced TaNAC4 expression. These results indicate that this novel TaNAC4 gene functions as a transcriptional activator involved in wheat response to biotic and abiotic stresses.

Characterization of a pathogenesis-related thaumatin-like protein gene TaPR5 from wheat induced by stripe rust fungus.

Pathogenesis-related (PR) proteins, induced in plants in response to various biotic and abiotic stresses, have been assumed to play a role in plant defense system. Proteins of the PR5 family, also named thaumatin-like proteins (TLPs), have been detected in numerous plant species. In this research, a novel PR5 gene, designated as TaPR5, was isolated and characterized from wheat leaves (cv. Suwon 11) infected by the stripe rust pathotype CY23 (incompatible interaction) using the rapid amplification of cDNA ends (RACE). TaPR5 was predicted to encode a protein of 173 amino acids with an estimated molecular mass of 17.6 kDa and a theoretical pI of 4.64. The deduced amino acid sequence of TaPR5 showed a significant sequence similarity with PR5 and TLPs from barley and other plants and contained a putative signal peptide at the amino terminus. Southern blot analysis indicated that TaPR5 is coded by a single-copy gene. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that TaPR5 transcript is significantly induced and upregulated in the incompatible interaction while in the compatible interaction a relative low level of the transcript was detected. TaPR5 was also induced by phytohormones (SA, JA and ABA) and stress stimuli (wounding, cold temperature and high salinity). Using an assay of onion epidermal cells indicated accumulation of TaPR5 protein in the apoplast. The immunocytochemical method showed that the TaPR5 protein was detected on cell walls of wheat leaves in the incompatible interaction at markedly higher labeling density compared with the compatible interaction.