Junxi Jiang

Wheat is a major staple crop in Xinjiang, China; however, comprehensive data on Fusarium mycotoxin contamination in wheat from this region remain limited. Despite recent observations of Fusarium head blight (FHB), few studies have characterized the mycotoxin profiles in wheat from Xinjiang, especially regarding emerging mycotoxins. This study aimed to systematically investigate the occurrence of both conventional and emerging mycotoxins in freshly harvested wheat from Xinjiang, to evaluate the effects of sampling year and geographical region on mycotoxin contamination levels, and to identify the Fusarium species responsible for mycotoxin production. A total of 151 freshly harvested wheat samples were collected from Southern and Northern Xinjiang in 2023 and 2024. Mycotoxins were quantified using high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS). Fusarium isolates were obtained and identified through the translation elongation factor 1-alpha (TEF-1α) gene sequencing. Genotyping was assessed by genotype-specific multiplex PCR, and mycotoxigenic potential was detected by rice culture assays. A high incidence (72.9%) of co-contamination with multiple mycotoxins was observed. Conventional mycotoxins such as deoxynivalenol (DON) and zearalenone (ZEN) were detected in 31.1% and 41.1% of samples. Notably, emerging mycotoxins, including enniatins (ENNs) and beauvericin (BEA), were present at significantly higher concentrations than those reported in some regions of China. Significant spatiotemporal variation was observed, with markedly higher contamination levels of emerging mycotoxins in 2024, particularly in Northern Xinjiang, where the symptoms of FHB epidemic occurred due to the humid climate and maize–wheat rotation system. Fusarium graminearum was identified as the primary producer of conventional mycotoxins, while F. acuminatum and F. avenaceum were mainly associated with emerging mycotoxins except BEA. This study provides the first comprehensive dataset on the co-occurrence of conventional and emerging Fusarium mycotoxins in wheat from Xinjiang and highlights significant spatiotemporal variations influenced by environmental factors. These findings underscore the necessity for continuous, region-specific monitoring and effective risk management strategies to address the evolving mycotoxin threat in Xinjiang’s wheat. Future research should focus on characterizing the populations of Fusarium toxin-producing fungi and the long-term impacts of mycotoxin exposure on food safety.

Pseudocercospora is a large cosmopolitan genus of plant pathogenic fungi that are commonly associated with leaf and fruit spots as well as blights on a wide range of plant hosts. P. actinidiae is a member of this genus, causing sooty spot on kiwifruit worldwide. With the expansion of kiwifruit cultivation, the incidence of sooty spot has become severe in Fengxin County, Jiangxi Province, China. Based on a survey conducted in 2022 across nine kiwifruit cultivars in six local orchards, the results showed that the disease incidence was higher in ‘Donghong’, ‘Jinyan’, ‘Jinkui’, ‘Fenghuang No. 1’, and ‘Jinguo’. In contrast, it was lower in ‘Gold3’ and ‘Hongshi No. 2’. No lesions were observed on ‘Kuilv’ and ‘Miliang No. 1’. Thirty-one fungal strains were isolated from infected leaves using single-spore isolation. Phylogenetic analysis of combined sequence data from the internal transcribed spacer region of ribosomal DNA (ITS), partial actin (actA), translation elongation factor 1-alpha (tef1), and the second largest subunit of RNA polymerase II (rpb2) sequence data, using maximum-likelihood and Bayesian inference, revealed their taxonomic placement within Pseudocercospora. Both morphological and molecular phylogenetic analysis supported Pseudocercospora fengxinensis as a new taxon within Pseudocercospora. Pathogenicity tests confirmed P. fengxinensis as the causal agent of sooty spot on kiwifruit. This study is the first report of P. fengxinensis causing sooty spot of kiwifruit worldwide, enriching our understanding of Pseudocercospora diversity in China and providing a foundation for improved disease management strategies.

In eukaryotes, the retromer complex is critical for the transport of cargo proteins from endosomes to the trans-Golgi network (TGN). Despite its importance, there is a lack of research on the retromer-mediated transport of cargo proteins regulating the growth, development, and pathogenicity of filamentous fungi. In the present study, transcriptome analysis showed that the expression levels of the retromer complex (CcVPS35, CcVPS29 and CcVPS26) were significantly elevated during the early stages of Corynespora cassiicola invasion. Gene knockout and complementation analyses further highlighted the critical role of the retromer complex in C. cassiicola infection. Subcellular localization analysis showed that the retromer complex was mainly localized to the vacuolar membrane and partially to endosomes and the TGN. Further research found that the retromer core subunit CcVps35 can interact with the cargo protein CcSnc1. Subcellular localization showed that CcSnc1 is mainly located at the hyphal tip and partially in endosomes and the Golgi apparatus. Deletion of CcVPS35 resulted in the missorting of CcSnc1 into the vacuolar degradation pathway, indicating that the retromer can sort CcSnc1 from endosomes and transport it to the TGN. Additionally, gene knockout and complementation analyses demonstrated that CcSnc1 is critical for the growth, development, and pathogenicity of C. cassiicola. In summary, the vesicular transport pathway involving the retromer complex regulates the sorting and transport of the cargo protein CcSnc1, which is important for the growth, development and pathogenicity of C. cassiicola.

Chilli pepper is one of the most important and widely cultivated pepper types in China. It has high nutritional and economic value. Capsicum frutescens L. is one of the chilli pepper types in production. In October 2022, a new disease showing blight of the entire chilli pepper plant was observed in Nanchang City, Jiangxi Province. The fungal isolates consistently obtained from the diseased samples were identified as Diaporthe caryae C. M. Tian & Qin Yang based on morphological characteristics, pathogenicity test and phylogenetic analysis of four genes, including internal transcribed spacer region (rDNA‐ITS), translation elongation factor 1‐alpha gene (TEF1), beta‐tubulin gene (TUB2), and calmodulin (CAL). Although other Diaporthe species have been reported as pathogens of peppers previously, to our knowledge, this is the first report of D. caryae causing stem blight of pepper in the world. D. caryae was reported to be able to infect various fruit trees such as kiwifruit, peach, pear, and pecan, resulting in kiwifruit rot, peach constriction canker, pear shoot canker, and pecan dieback, respectively. The host range of D. caryae has expanded from fruit trees to vegetable crops.

Tea (Camellia sinensis (L.) O. Kuntze), a perennial evergreen shrub, is one of the most important cash crops in China. In September 2021, leaf spot symptoms were observed on approximately 30% of te...

Rohdea japonica, known as Japanese sacred lily, a perennial herb in the family Asparagaceae, is an important ornamental plant in China (Hinkley 2006). In May 2022, at the campus of Jiangxi Agricult...

Taro (Colocasia esculenta), a perennial tuberous herb of the family Araceae, is cultivated widely in southern China. In December 2020, postharvest corm rot occurred on taro of 5 tons with approximately 70% incidence in a 18 square meter cellar in the Qingshanhu District (115°83’E, 28°76’N) of Nanchang City, Jiangxi Province, China. Infected corms had round, soft and slightly sunken lesions covered with white mycelia. The lesions gradually expanded, causing part or whole corm to become soft and shrink, and the inner corm tissue turned brown and rotten. To isolate the pathogen, a total of 30 diseased corm samples were collected. The corms were surface-disinfected by wiping them with 70% ethanol and then passing them over flame back and forth for 5 s. After epidermal tissue of the corms was removed using a sterilized scalpel, small portions of the inner tissue were transferred onto potato dextrose agar (PDA) and incubated at 25°C in the dark. A total of 27 isolates forming Fusarium-like colonies were obtained using monosporic isolation, of which 11 isolates were identified as F. oxysporum and 16 isolates were identified as F. proliferatum based on the colony characteristics and conidial morphology (Leslie and Summerell, 2006). Colonies of F. oxysporum isolates produced dense whitish to light purple mycelia with dark red pigments. Macroconidia were sickle-shaped, straight to slightly curved, 3-5 septa, measuring 25.6 to 45.8 × 3.3 to 6.1 µm. Microconidia were hyaline, oval or ellipsoid, aseptate, and measured 5.2 to 11.8 × 2.2 to 3.5 µm. Chlamydospores were round, 3.5 to 7.6 µm in diameter. Colonies of F. proliferatum isolates were whitish with abundant aerial mycelia and orange pigments. Numerous oval unicellular microconidia were 4.5 to 11.8 × 1.9 to 4.2 µm, and sparse falcate macroconidia with 3-4 septa were 19.4 to 39.2 × 1.9 to 5.2 µm in size. No chlamydospores were observed. Genomic DNA of two representative isolates (F. oxysporum isolate YTU1 and F. proliferatum isolate YTH1) was extracted, and the internal transcribed spacer (ITS) region and translation elongation factor 1-α (TEF1-α) gene were amplified and sequenced using primers ITS1/ITS4 and EF-1H/EF-2T (White et al., 1990; Zhang et al., 2014) respectively. Using BLAST analysis, the ITS sequences of isolates YTU1 (506 bp) and YTH1 (508 bp) exhibited 100% homology with F. oxysporum (MN633363) and F. proliferatum (MT534188), respectively, and the TEF1-α sequences of YTU1 (712 bp) and YTH1 (703 bp) shared 100% homology with F. oxysporum (MN507110) and F. proliferatum (MK952799), respectively. Sequences were deposited in GenBank with the Accession Nos. MZ157124 and MZ310443 for ITS, and MZ383814 and MZ383815 for TEF1-α. The pathogenicity of each isolate was determined on six healthy taro corms. All the taro corms were surface-disinfected with 70% alcohol and two locations from each corm were inoculated. One location was inoculated with 20 μl of conidial suspension (1×105 conidia/ml) and the other was inoculated with sterilized water as a control. All corms were incubated in a growth chamber at 25℃ and 95% relative humidity in the dark. After 15 days, all inoculated corms developed brown rot symptoms, while the non-inoculated control corms remained symptomless. The original isolates were successfully reisolated from all symptomatic corms and identified by sequencing, fulfilling Koch's postulates. F. oxysporum has been reported causing postharvest corm rot of taro in Bogor, Japan, and British Solomon Islands (Widodo et al., 2011). However, to our knowledge, this is the first report of F. oxysporum causing postharvest corm rot of taro in China and F. proliferatum causing postharvest corm rot of taro in the world. The disease poses a potential threat to taro production and should be timely assessed and properly managed.

Blueberry (Vaccinium virgatum), a member of the Ericaceae family, is an increasingly important crop in China because of its abundant nutritional benefits and economic value (Kuzmanović et al. 2019)...

Ripe rot caused by Botryosphaeria dothidea causes extensive production losses in kiwifruit (Actinidia chinensis Planch.). Our previous study showed that kiwifruit variety “Jinyan” is resistant to B. dothidea while “Hongyang” is susceptible. For a comparative analysis of the response of these varieties to B. dothidea infection, we performed a transcriptome analysis by RNA sequencing. A total of 305.24 Gb of clean bases were generated from 36 libraries of which 175.76 Gb was from the resistant variety and 129.48 Gb from the susceptible variety. From the libraries generated, we identified 44,656 genes including 39,041 reference genes, 5,615 novel transcripts, and 13,898 differentially expressed genes (DEGs). Among these, 2,373 potentially defense-related genes linked to calcium signaling, mitogen-activated protein kinase (MAPK), cell wall modification, phytoalexin synthesis, transcription factors, pattern-recognition receptors, and pathogenesis-related proteins may regulate kiwifruit resistance to B. dothidea. DEGs involved in calcium signaling, MAPK, and cell wall modification in the resistant variety were induced at an earlier stage and at higher levels compared with the susceptible variety. Thirty DEGs involved in plant defense response were strongly induced in the resistant variety at all three time points. This study allowed the first comprehensive understanding of kiwifruit transcriptome in response to B. dothidea and may help identify key genes required for ripe rot resistance in kiwifruit.