Persea americana (avocado) is a healthy fruit, rich in unsaturated fatty acids, various minerals, and vitamins. As avocado cultivation continues to expand globally, its development is increasingly constrained by concomitant diseases, among which fruit rot and anthracnose have emerged as significant threats to fruit quality. Menglian in Yunnan Province is the largest avocado production area in China. In November 2024, fruit rot was observed on avocado fruits in Yunnan, China, characterized by reddish-brown discoloration, premature ripening, softening, and pericarp decay, with a field infection rate of 22%. Concurrently, anthracnose was detected in avocado fruits, presenting as small dark brown spots that developed into irregular rust-colored lesions, followed by dry rot depressions, ultimately leading to soft rot, peeling, or hardened dry rot, with a field infection rate of 15%. Infected fruit samples were collected, and fungal strains were isolated, purified, and inoculated via spore suspension, followed by re-isolation. The strains were conclusively identified as Diaporthe phaseolorum (SWFU20, SWFU21) and Colletotrichum fructicola (SWFU12, SWFU13) through an integrated approach combining DNA extraction, polymerase chain reaction (PCR), sequencing, phylogenetic reconstruction, and morphological characterization. This is the first report of D. phaseolorum causing fruit rot and C. fructicola causing anthracnose on avocado in China. In future research, we will test methods for the control of D. phaseolorum and C. fructicola. The identification of these pathogens provides a foundation for future disease management research, supporting the sustainable development of the avocado industry.

Bursaphelenchus xylophilus is a pathogenic nematode responsible for pine wilt disease, which can cause the demise of pine trees and discoloration of trunks. As rotenone is an important botanical pesticide, its impact on B. xylophilus was investigated through RNA-seq to understand the response mechanism of nematode. The bioassay results yielded the 12-h LC₃₀ (1.35 mg L^-1) and LC₅₀ (2.60 mg L^-1) values for rotenone. Differential gene expression analysis identified 172 and 614 differentially expressed genes (DEGs) in B. xylophilus exposed to two different concentrations of rotenone (1.35 and 2.60 mg L^-1). To validate these findings, the expression patterns of 10 DEGs were confirmed through RT-qPCR. Additionally, all DEGs were categorized into eight gene expression profiles using STEM. Notably, the gene ontology (GO) processes of "single-organism process," "metabolic process," and "catalytic activity" were prominently enriched in rotenone-treated samples, suggesting a role for metabolic and catalytic pathways in the nematode's response to rotenone stress. KEGG pathways related to "carbon metabolism," "drug metabolism-cytochrome P450," and "metabolism of xenobiotics by cytochrome P450" were similarly enriched, indicating potential mechanisms for detoxification resistance and oxidative stress resistance. The analysis pointed to the pivotal roles of detoxification- and oxidoreduction-related genes, as well as signal transduction-related genes, in enabling B. xylophilus to adapt to rotenone exposure. These insights could markedly enhance our understanding of nematode resistance mechanisms and potentially inform the development of more effective rotenone-based strategies for controlling B. xylophilus.

Glutamate-gated chloride channels (GluCls), a class of ion channels found in the nerve and muscle cells of invertebrates, are involved in vital life processes. Bursaphelenchus xylophilus, the pathogen of pine wilt disease, has induced major economic and ecological losses in invaded areas of Asia and Europe. We identified 33 GluCls family members by sequence alignment analysis. A subsequent bioinformatic analysis revealed the physicochemical properties, protein structure, and gene expression patterns in different developmental stages. The results showed that GluCls genes are distributed across all six chromosomes of B. xylophilus. These proteins indicated a relatively conserved structure by NCBI-conserved domains and InterPro analysis. A gene structure analysis revealed that GluCls genes consist of 5 to 14 exons. Expression pattern analysis revealed BxGluCls were extensively involved in the development of second instar larvae of B. xylophilus. Furthermore, BxGluCls15, BxGluCls25, and BxGluCls28 were mainly associated with the development of eggs of B. xylophilus. BxGluCls12, BxGluCls18, and BxGluCls32 were predominantly linked to nematode resistance and adaptation. Investigation the structure and expression patterns of BxGluCls is crucial to understand the developmental trends of B. xylophilus. It also helps identify molecular targets for the development of biopesticides or drugs designed to control this nematode.

Macadamia integrifolia, a tropical and subtropical fruit tree with significant economic and nutritional value, faces serious fungal disease problems during cultivation that severely affect yield and quality. In November 2024, leaf blight symptoms of M. integrifolia were observed in Menglian, Pu’er, Yunnan, China, with a disease incidence of 23% in the field. Initial symptoms included small spots that enlarged into circular to irregular lesions with red-brown centers and brown to black margins. Finally, the leaves turned yellow and became scorched, eventually leading to massive leaf shedding. Infected leaf samples were collected, and fungal strains were isolated, purified, and inoculated via spore suspension, followed by re-isolation. The strains were conclusively identified as Pestalotiopsis colombiensis (SWFUCB2, SWFUCB1) through an integrated approach combining DNA extraction, polymerase chain reaction (PCR), sequencing, phylogenetic reconstruction, and morphological characterization. This is the first report of P. colombiensis causing M. integrifolia leaf blight disease in China, filling a gap in research on this disease. This study provided important information for epidemiological research on this disease and the development of comprehensive leaf blight disease control strategies.

Introduction: Pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, poses a significant threat to global pine forests. The sulfate permease (SULP) family is essential for sulfate transport, sulfur assimilation and cellular homeostasis, yet it remains uncharacterized in B. xylophilus. This study aimed to comprehensively identify all members of the SULP family in B. xylophilus and to elucidate their roles in nematode development and stress adaptation.Methods: Through genomic data analysis, we identified 10 members of the SULP family in B. xylophilus and conducted a comprehensive characterization of their physicochemical properties, conserved motifs, protein structures, and gene expression profiles across different developmental stages.Results: The results revealed Bx-sulps were located on 5 chromosomes of B. xylophilus. Phylogenetic analysis unveiled both conserved and divergent evolutionary patterns of these proteins compared to counterparts in other nematodes. Expression analysis demonstrated upregulation of Bx-sulps during the dauer third-instar larva (D3) stage, suggesting their involvement in stress response and diapause. Moreover, certain Bx-sulps exhibited high expression levels in adult stages, indicating a potential role in reproductive processes.Discussion: The study presents the first comprehensive examination of BxSULP family, shed light on its significance in nematode development and stress adaptation. These findings provide the groundwork for further functional investigations and may aid in the development of targeted strategies for managing PWD.