Guangdong Academy of Forestry

Morphological characters of beetles can differ greatly, even within a single species, necessitating the integration of molecular techniques and ecological data for accurate taxonomical delineation, particularly within taxonomically challenging groups. Chrysobothris, a world-distributed genus of considerable size with a homonymy rate exceeding 1/5, frequently presents ambiguities in species boundaries. In this research, a series of Chrysobothris specimens collected from southern China were segregated into four sharply contrasting external morphotypes. A taxonomic ambiguity was initially posed: whether they represented several species, intraspecific polymorphism within a single species, or geographic/intraspecific variants of the similar species Chrysobothris violacea Kerremans, 1892. COI barcoding and phylogenetic analyses supported the conspecificity of these morphotypes and confirmed their distinction from C. violacea at the species level. Based on integrated evidence, we describe these specimens as Chrysobothris borealina Huang, Wu & Song, sp. nov., provide diagnostic characters with illustrations, and compare the new species with C. violacea. The species occurs in mid- to high-elevation pine and pine-broadleaf mixed forests and differs from C. violacea in both elevational range and phenology, indicating potential ecological differentiation. Additionally, we document a rare instance of a nymphal parasitengone mite (cf. Erythraeidae) attached to one female specimen.

Leaf senescence is a crucial developmental process in plants, and is tightly regulated by transcription factors such as NAC family members. However, the functions of NAC genes in the leaf senescence of the medicinal and ornamental plant Clerodendrum japonicum remain largely uncharacterized. In this study, we performed the transcriptome sequencing of mature and early-senescent leaves in C. japonicum. We screened candidate NAC genes and validated their expression patterns using quantitative real-time PCR (qRT-PCR). The functions of CjNAC43 and CjNAC54 were characterized through heterologous overexpression in Arabidopsis thaliana and Virus-Induced Gene Silencing (VIGS) in C. japonicum. We further investigated their roles in abscisic acid (ABA)- and dark-induced senescence. Our findings revealed that transcriptomic analysis identified 522 differentially expressed genes, including nine NAC members. CjNAC43 and CjNAC54 exhibited significantly upregulated expression during the critical senescence phase (90–130 days). Overexpression of either gene in A. thaliana accelerated leaf senescence, up-regulated senescence-associated genes (SAGs), and reduced chlorophyll content. Conversely, silencing CjNAC43 or CjNAC54 in C. japonicum delayed senescence. Both genes enhanced the plant’s sensitivity to ABA and darkness, leading to accelerated senescence under these stresses. In conclusion, our results demonstrate that CjNAC43 and CjNAC54 function as positive regulators of leaf senescence in C. japonicum, partly by mediating ABA and dark signaling pathways.

Background: Mycetia, a subshrub genus within the subfamily Rubioideae (Rubiaceae), is predominantly distributed in tropical Asia, lacking comprehensive plastid genomic resources. This study aimed to characterize the complete plastid genomes of two Mycetia species and explore their structural features and evolutionary relationships. Methods: The plastid genomes of Mycetia hirta and Mycetia sinensis were sequenced and assembled. We analyzed genome structure, simple sequence repeats (SSRs), long repeats, codon usage, nucleotide diversity (π), and Ka/Ks and conducted phylogenetic analysis. Results: Both genomes exhibited a typical quadripartite structure (153,989–154,588 bp; GC content 37.7–37.8%), encoding 126 genes (86 protein-coding, 8 rRNA, and 32 tRNA). Both chloroplast genomes contained 52–60 SSRs and three repeat types with minor interspecific differences. Junction regions and codon usage were highly conserved, with slight variations in RSCU values. The average π was 0.0096, and the non-coding trnE-trnT (π = 0.0817) emerged as a potential DNA barcode. The average Ka/Ks was 0.2900, indicating purifying selection. Phylogenetic analysis confirmed the monophyly of Mycetia within Argostemmateae. Conclusions: This study provides the first comparative plastid genomic analysis for Mycetia, enhancing our understanding of its genetic diversity and supporting future phylogenetic and taxonomic research on the genus.

Abstract The evolutionary arms race between insects and their predators has fueled remarkable defensive adaptations, offering insights into ecological dynamics across deep time. Fossils provide critical evidence for studying the evolution of defense strategies. Here, we describe a new lineage of Clambidae from mid‐Cretaceous Kachin amber, Scutacalyptus kolibaci gen. et sp. nov. Scutacalyptus stands out within the family due to the flattened body and fully explanate body margins. The diversity of defensive morphotypes in Cretaceous Clambidae, including conglobators like Sphaerothorax , semi‐flattened forms like Acalyptomerus , and shield‐formers like Scutacalyptus , highlights their developmental plasticity and suggests ecological differentiation in response to varied predation pressures during the late Mesozoic. This morphological divergence reflects niche partitioning in the Cretaceous forest floor ecosystem, driven by a diverse predator array including spiders, ants, lizards, and birds. The coexistence of clambids with spines or explanate margins parallels adaptations in the modern, unrelated Cassidinae, where tortoise beetles use explanate margins and some leaf‐mining beetles use spines, each tailored to counter specific predation pressures. These parallel strategies reveal how different defenses likely addressed distinct ecological challenges in the mid‐Cretaceous.

The xyloglucan endotransglucosylase/hydrolase (XTH) gene family plays a crucial role in fruit development and texture regulation. We used the telomere-to-telomere genome of 'Wanfeng' almond to identify and analyse the XTH gene family, examining protein physicochemical properties, phylogenetic relationships, protein conserved motifs, gene structure, gene replication, and expression patterns. We identified 23 PdXTH family members through the telomere-to-telomere level genome of 'Wanfeng' almond. These genes exhibited significant variations in protein physicochemical properties, gene structure, and sequence conservation. PdXTH genes were predominantly distributed in the I/II subfamily and demonstrated high sequence conservation and gene structure similarity. Gene duplication events contributed to an increase in PdXTH family members. Analysis of cis-acting elements suggest that PdXTH genes are involved in almond growth and development, stress response, and hormone regulation. Expression patterns revealed that PdXTH genes display significant tissue-specific expression. PdXTH genes had notable temporal gradient changes during fruit development and may function at different development stages. The sustained high expression of PdXTH genes throughout almond fruit development represents a potential mechanism for maintaining fruit firmness. Furthermore, transgene studies confirmed that PdXTH2 has a regulatory role in programmed cell death. PdXTH2 is localized to the cell membrane. PdWRKY24 and PdbHLH92 can directly bind to the PdXTH2 promoter region and positively regulate its transcriptional activity. In conclusion, this study provides new insights into the role of the XTH family in plant physiology.

IntroductionEvaluating soil quality is essential for guiding reforestation and land management strategies, particularly in degraded Chinese fir plantations where long-term productivity and successional dynamics remain poorly understood.MethodsThis study assessed ten mixed-species planting patterns to quantify the Soil Quality Index (SQI) using a Minimum Data Set (MDS) approach, which reduces data redundancy by statistically identifying key indicators from a larger dataset, thereby effectively capturing essential soil functions, and subsequently explored the relationships between SQI and stand growth, structural diversity, biomass, net primary productivity (NPP), as well as percentage of broadleaf species (PBS).ResultsSignificant differences were observed across planting patterns in diameter at breast height (DBH), tree height (TH), stand biomass (FB), structural diversity (variation in DBH [CVD] and Gini coefficient [GiniD]), and PBS. Soil properties—including physical (soil moisture), chemical (soil organic carbon [SOC], total nitrogen [TN], total phosphorus [TP], ammonium nitrogen [NH₄⁺], nitrate nitrogen [NO₃⁻], available phosphorus [AP]), microbial (microbial biomass carbon [MBC], nitrogen [MBN], and phosphorus [MBP]), and enzymatic (e.g., peroxidase [POD], alkaline phosphatase [ALP], urease [URE])—also varied significantly. SQI values ranged from 0.42 to 0.65, with patterns Fir–Mytilaria laosensis mixed (ML), Fir–Castanopsis hystrix mixed (CH), Fir–Michelia chapensis mixed (MC), and Fir–Schima superba mixed (SS) associated with both high SQI and greater biomass. Sensitivity analysis identified Fir–Cinnamomum porrectum mixed (CP), ML, and SS as particularly responsive to hybridization. Among soil factors, URE, AP, and MBC were key drivers of productivity, while URE, AP, MBC, and POD significantly predicted the proportion of broadleaf trees. Enhanced soil quality was positively associated with increases in DBH, TH, and PBS, accelerating the successional transition from fir-dominated to broadleaf-dominated stands. However, SQI was not significantly correlated with structural diversity metrics.DiscussionThese results underscore the importance of rational species selection in restoring degraded fir plantations and demonstrate that improving soil quality is a critical mechanism promoting near-natural forest succession.