IDENTIFICATION OF PEDILANTHUS LEAF CURL VIRUS AND A NOVEL BETASATELLITE-INFECTING RADISH (RAPHANUS SATIVUS L.) IN PAKISTAN

First Report of a ‘ Candidatus Phytoplasma australasiaticum’ Strain Associated with Bamboo Witches’ Broom Disease in Guangdong, China

The need to identify insect vectors and alternative hosts, which will provide theoretical guide to the control of Bamboo Witches’ Broom Disease is highlighted.

First report of a ‘ Candidatus Phytoplasma australasiaticum’-related strain (subgroup 16SrII-A) associated with phyllody symptoms of Cyanthillium cinereum in Taiwan

Little ironweed (Cyanthillium cinereum; syn. Vernonia cinerea) is an herbaceous plant in the Asteraceae family (Trang et al. 2024). The plant is distributed in Asia, Australia and Africa, and has been used as a traditional medicine (Trang et al. 2024). In January 2026, little ironweed plants exhibiting phyllody symptoms (Fig. S1) were observed in a grass-covered area (measuring 3 m × 6 m) in Qishan District, Kaohsiung, Taiwan. Around 8% (22/285 plants) of the population showed symptoms. Six symptomatic and four asymptomatic plants were collected. Flower-like tissues from symptomatic plants were collected for DNA extraction with a Synergy 2.0 Plant DNA Extraction Kit (OPS Diagnostics). For asymptomatic plants, capitula were used instead. One DNA sample was extracted for each plant. The samples were first tested with primers specific to the plant’s 26S rDNA (28KJ/28C; Cullings 1992), and all of them produced the target amplicon (~0.69 kb), indicating sufficient quality for polymerase chain reaction (PCR). Nested PCR targeting phytoplasmas’ 16S rDNA was conducted with outer and inner primer pairs P1/P7 and fU5/rU3 (Lorenz et al. 1995). In all PCR assays, negative controls (nuclease-free water) were included. All samples from symptomatic plants amplified the outer and inner amplicons (~1.81 kb and ~0.88 kb), whereas DNA from the asymptomatic plants did not. After assembling sequences of the outer and inner fragments for each symptomatic sample, identical 16S rDNA sequences were found. A representative sequence was deposited in GenBank (1,459 bp; accession no. PZ193724), and BLASTn search against GenBank revealed that it was identical to that of a reference phytoplasma strain belonging to subgroup 16SrII-A (NCHU2014; accession no. CP040925; 100% identity, 100% query coverage; Rodrigues Jardim et al. 2023). A 1,248-bp fragment within the obtained sequence was further analyzed using iPhyClassifier (https://plantpathology.ba.ars.usda.gov/cgi-bin/resource/iphyclassifier.cgi), and its virtual RFLP pattern was the same as 16SrII-A’s reference pattern (similarity coefficient = 1.00; accession no. L33765). The detected phytoplasma’s identity was further confirmed by amplification and sequencing of the elongation factor Tu (tuf) and protein translocase (secY) genes. Fragments containing tuf and secY were respectively amplified by primer sets TUF-II-F1/TUF-II-F2/TUF-II-R1 (for semi-nested PCR; Al-Subhi et al. 2017) and SecYF1(II)/SecYR1(II) (for PCR; Lee et al. 2010). The tuf sequences were obtained from the inner amplicon, whereas sequences of secY were obtained by sequencing followed by primer walking (accession nos. PZ377067 and PZ377068). The detected phytoplasma and the reference strain NCHU2014 (‘Ca. Phytoplasma australasiaticum’-related strain; 16SrII-A; accession no. CP040925) shared identical sequences for both tuf (986 bp; partial) and secY (1,263 bp; complete) fragments. This is the first report of little ironweed infected by a 16SrII-A phytoplasma in Taiwan; this specific host-pathogen association has only been reported in Hainan Province of China (Yu et al. 2024). Because 16SrII-A phytoplasma can infect economic crops in Taiwan (Wu et al. 2026) and little ironweed is widely distributed in the island, it is possible that the weed may represent a potential reservoir host. Thus, monitoring and eradication of symptomatic little ironweed is advisable in crop production areas.

First Report and Morpho-Molecular Characterization of Boeremia Exigua Causing Leaf Spot of Mungbean (Vigna Radiata (L.) Wilczek)

Molecular evidence of two begomoviruses and a novel DNA-B infecting Duranta erecta variegata in Pakistan.

This is the first report of RoLCuV, a novel DNA-B, PaLCrV, and HYVA infecting D. erecta variegata in Pakistan, and the presence of rose leaf curl virus accompanied by a novel recombinant DNA-B, tentatively named "rose leaf curl virus DNA-B."

Genomic insights and pathogenic potential of begomovirus infecting bitter gourd (Momordica charantia L.) in Tamil nadu, India

Quantitative PCR showed viral accumulation of 105–10⁹ copies/μL, confirming the synergistic role of DNA-B and betasatellites in severe symptom induction and systemic infection, underscoring the complexity of begomovirus pathogenesis.

Isolation, identification, and pathogenicity determination of fungal pathogens causing root rot of Stipa bungeana in Inner Mongolia, China

Stipa bungeana Trin. is a dominant grass species in the warm temperate steppes of northern China; however, its root rot diseases have not been systematically investigated. In this study, 100 root samples of S. bungeana showing typical root rot symptoms were collected from the Sha’erqin Research Base in Tumd Left Banner, Hohhot City, Inner Mongolia, China. A total of 76 fungal isolates, were recovered and identified based on morphological characteristics and multi-locus sequence analysis of the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (TEF1-α), and the second largest subunit of RNA polymerase II (RPB2) gene. Eight species were identified, of which Curvularia spicifera (25 isolates, 32.89%) and Microdochium bolleyi (24 isolates, 31.58%) were the predominant species. Pathogenicity tests conducted on healthy S. bungeana seedlings under greenhouse conditions demonstrated that all 8 species induced root rot symptoms, thereby, fulfilling Koch’s postulates. Notably, C. spicifera and M. bolleyi exhibited significantly greater virulence than the Fusarium species and the other recovered fungi, resulting in higher disease incidence and plant mortality. This study represents the first comprehensive report of the fungal pathogens associated with root rot of S. bungeana in China and provides the first evidence that C. spicifera and M. bolleyi are the predominant and most virulent pathogens associated with root rot of Stipa species. These findings fill an important critical knowledge gap in grassland plant pathology and provide a scientific foundation for disease management in natural steppe ecosystems.