‘Candidatus Liberibacter asiaticus’ is the bacterium associated with the citrus disease known as huanglongbing (HLB). This study evaluated the influence of ‘Ca. L. asiaticus’ infection on a number of key plant physiological variables concerning photosynthesis, cell integrity, reactive oxygen species scavengers’ activity, and osmoregulation of two different species of citrus—the pomelo Citrus maxima and the mandarin C. reticulata ‘Tankan’—relative to their measured ‘Ca. L. asiaticus’ infection load. Results indicated that all measured physiological variables except soluble sugar were affected by increased ‘Ca. L. asiaticus’ infection titers, wherein the variety C. maxima proved overall more resistant than C. reticulata. ‘Ca. L. asiaticus’ infection was linked in both plants to decrease in chlorophyll concentration, cell membrane permeability, and malondialdehyde, as well as increased free proline and starch contents. Chlorophyll fluorescence measurements taken 9 months after grafting the mandarin C. reticulata with ‘Ca. L. asiaticus’ scions revealed a significant decrease in the photosynthesis variables maximum photochemical quantum yield of photosystem II (PSII), effective photochemical quantum yield of PSII, and coefficient of photochemical fluorescence quenching assuming interconnected PSII antennae, whereas nonphotochemical fluorescence quenching increased significantly; C. maxima plants, on the other hand, did not show significant differences until the 12th month from infection exposure. The variables superoxide dismutase, catalase, peroxidase, and soluble protein initially increased and later decreased. In addition, progression of ‘Ca. L. asiaticus’ replication in both citrus species was accompanied by rapid changes in three reactive oxygen species scavenging enzymes in C. maxima, while the pattern was different in C. reticulata. We hypothesize that the observed interspecific differences in physiological change are related to their relative resistance against ‘Ca. L. asiaticus’ infection. These results provide a scaffold for better describing the pathogenesis, selecting the most resistant breeds, or even validating pertaining omics research; ultimately, these detailed observations can facilitate the diagnosis of ‘Ca. L. asiaticus’ infection.

Red rust disease, caused by the algal pathogen Cephaleuros spp., poses an increasingly significant threat to oolong tea (Camellia sinensis) cultivation. Currently, however, effective management is hindered by a lack of species-specific diagnostic methods and limited analysis of host-response physiological changes. In this study, the region-wide survey was conducted, species-specific molecular diagnostics, multi-scale microscopy, and host biochemical analysis (pigments and antioxidants) were utilized to investigate Cephaleuros diversity, invasion biology, and host responses in oolong tea. Across 785 composite leaf samples, the overall Cephaleuros positivity rate was 30.19%, with incidence significantly higher detection rate in Chaozhou, Guangdong (46.59%) than in Fujian (7.58%). Genotyping via psaA-targeted qPCR revealed strikingly distinct regional distributions: C. parasiticus was predominantly detected in Chaozhou (95.3%), whereas C. virescens was the only identified species in Fujian, with no mixed infections identified. Histological analysis of Chaozhou samples revealed subepidermal thalli beneath both leaf surfaces, accompanied by palisade/spongy necrosis, which suggested deeper tissue invasion by C. parasiticus. To characterize host responses, we quantified photosynthetic pigments and antioxidant enzymes in lesion centers and margins across representative cultivars. In green-leaf cultivars, infection was generally associated with decreases in chlorophyll a and b (with significance varying by cultivar), whereas carotenoid responses were modest and cultivar dependent. In contrast, two etiolated mutants exhibited significant increases in chlorophyll a (2.0–3.7-fold) and carotenoids (~1.5–1.6-fold), and anthocyanin increased by ~62% in the etiolated Juduozai mutant. Antioxidant enzyme activity was spatially structured, with peroxidase (POD) and catalase (CAT) strongly induced at lesion margins (POD increase 39–248%), while lesion centers exhibited reduced activity (5-41%). Superoxide dismutase (SOD) showed a modest increase at the lesion margins (increase 18–31%). A composite "reaction index" (POD+SOD at lesion margins) was used to classify cultivars into high and moderate response categories. These findings provide new insights into the ecological dynamics and host responses associated with Cephaleuros infection in oolong tea and highlight the potential for using these indicators in cultivar selection and disease management strategies.

Background: Mangrove plants are a core component of coastal ecosystems, directly influencing biodiversity and shoreline stability. However, in recent years, due to the combined pressures of human activities and climate change, nearly half of the mangrove species in China are endangered and require urgent conservation measures. This study analyzed the population dynamics and stress factors affecting four rare and endangered mangrove species—Lumnitzera racemosa, Ceriops tagal, Barringtonia racemosa, and Heritiera littoralis—on the Leizhou Peninsula, providing scientific evidence for their conservation. Methods: Field surveys and plot investigations were conducted, with population dynamics and structure quantified using static life tables, survival rates, mortality rates, and disappearance curves. Additionally, the MaxEnt species distribution model and GIS technology were applied to predict the potentially suitable distribution areas. Results: The findings revealed that the population of L. racemosa exhibits an atypical pyramid structure, with few seedlings and constraining population growth potential. The C. tagal population follows an irregular pyramid structure, with abundant seedlings but fewer mature individuals, suggesting a rapid decline followed by stability. The B. racemosa population also follows an irregular pyramid structure, with many seedlings and a greater proportion of middle-aged and older individuals, facing the risk of early mortality. The H. littoralis population is also in decline, with few seedlings and a severe risk of local extinction. MaxEnt model predictions indicated that temperature is the primary environmental factor, with Area Under the Curve (AUC) values for all species exceeding 0.8, indicating strong predictive ability. The predicted potential suitable areas showed an expanded distribution range compared to current distribution points, providing valuable references for species introduction and propagation. Conclusions: This study described the population structure of the four mangrove species on the Leizhou Peninsula and assessed their primary stress factors. The results provided a theoretical basis for the conservation and restoration of endangered mangrove species and offer important guidance for developing effective conservation strategies in southern China.

Psyllids (Hemiptera: Psylloidea) are economically important sap-feeders, yet comparable mitochondrial genome (mitogenome) resources remain unevenly developed, partly because amplification success is often lineage-dependent. We designed 6 candidate broad-range long-PCR primer pairs from alignments of 60 published psyllid mitogenomes and evaluated them using a long-PCR/Sanger workflow and independent Illumina resequencing across 7 species representing 4 sampled families. The primer sets recovered near-complete mitogenomes across the sampled taxa, and cross-platform comparisons were fully concordant outside the control region, supporting recovery of protein-coding, ribosomal RNA, and transfer RNA (tRNA) regions. The control-region amplicon of Diaphorina citri showed multiple bands and was therefore interpreted separately. Comparative analyses of 67 mitogenomes identified genewise differences in nucleotide diversity, conserved primer-binding windows, and lineage-restricted mitochondrial tRNA structural variants involving trnCys, trnGlu, trnGly, and trnHis. Nucleotide- and amino-acid-based phylogenies recovered broadly similar family-level structure but differed at unstable deep nodes involving Diaphorina and Diclidophlebia paucipunctata. Saturation diagnostics indicated that the mitochondrial signal was not fully saturated overall, although third codon positions showed the strongest saturation tendency. Relaxed-clock analyses using 2 calibration strategies bracketed the crown age of Psylloidea at ∼49 to 129 Ma, indicating that the resulting dates should be viewed as calibration-sensitive hypotheses rather than definitive age estimates. This workflow provides a practical framework for generating comparable Psylloidea mitogenomes while highlighting the need for additional empirical validation in unsampled families and for nuclear data to resolve unstable deep relationships.

Psyllids (Hemiptera: Psylloidea) are recognized as economically important sap-feeders. To enable broad mitogenome recovery, universal long-PCR primers were designed from alignments of 60 published mitogenomes and were validated by benchmarking Sanger-based assemblies against Illumina resequencing across seven species ( Blastopsylla occidentalis , Cornegenapsylla sinica , Macrohomotoma gladiata , Cacopsylla citrisuga , Cacopsylla chinensis , Diaphorina citri , and Bactericera cockerelli ). Single amplicon bands were obtained for each primer set, excepting for multiple bands with the control region (CR) of Diaphorina citri ; each assembly using Sanger sequences was confirmed by Illumina sequencing, independently. Resulting mitogenomes (14,499–15,220 bp) showed high cross-platform concordance, with read depths 193–72,903×. Sliding-window nucleotide diversity across 67 mitogenomes (CR excluded) indicated nad2 , atp8 , nad5 , and nad6 as most variable, whereas cox1 , cox2 , and both rRNAs were most conserved; primer sites lay within low-diversity windows (mean Pi ≤ 0.07). Four lineage-restricted tRNA secondary-structure variants were observed: trnCys , trnGlu , trnGly , trnHis . Phylogenies inferred by maximum likelihood (ML) and Bayesian inference (BI) were largely congruent and resolved family clades as strongly monophyletic; however, the placement of Diaphorina and Diclidophlebia paucipunctata was sensitive to data type, with amino-acid PCG analyses supporting Diaphorina within Psyllidae (Fig. S4) while nucleotide all-gene analyses yielded an alternative Bayesian placement. Relaxed-clock analyses dated crown Psylloidea to the Early Cretaceous (~ 130 Ma; 95% HPD 114–146), with major family divergences concentrated in the Cretaceous (~ 105–98 Ma). This validated workflow expands mitogenomic resources and provides practical marker guidance for barcoded surveillance, pathway inference, and vector risk assessment within integrated pest management.

Phyllanthus emblica is valued for its nutritional and medicinal properties, yet the genomic divergence between localized and widespread cultivars remains poorly understood. We investigated the genomes of two individuals from the endemic cultivar ‘Hongguang’ (HG), propagated via regional grafting, and the commercially widespread ‘Dongkeng’ (DK), known for its superior protein content. Using whole-genome sequencing, we reconstructed phylogenies from two nuclear markers, profiled genome-wide variations, assembled chloroplast genomes, and verified relative plastid copy numbers via real-time quantitative PCRs (qPCRs). Nuclear internal transcribed spacer (ITS) and phytochrome C (PHYC) phylogenies confirmed both samples belonged to the P. emblica lineage, while revealing a distinct genetic identity for the HG individual. Genome-wide variant profiling of the two individuals identified KEGG enrichment in plant hormone signaling pathways; DK variants mapped to the canonical auxin axis, while HG variants were annotated to reversible protein phosphorylation. Comparative chloroplast genomics demonstrated shared maternal inheritance and shared mutations in key photosynthetic genes (psaB, petA, and the ndh cluster) between the two genomes, though qPCR validation revealed a higher relative chloroplast DNA copy number in the DK sample. Despite the two-individual limitation, these findings revealed preliminary genomic variations, offering candidate molecular markers for future population studies and marker-assisted breeding.