White leaf spot in maize (WLS) severely threatens maize yield and quality. Risk assessment suggests that it may become one of the most significant maize diseases in China. Exogenous arachidonic acid offers a novel strategy for enhancing crop stress resistance. This study aims to investigate the effects and mechanisms of ARA in inducing resistance against WLS. The study found that 15 µM ARA effectively induces systemic resistance in maize against WLS. This resistance manifests as a multi-layered synergistic defense response. ARA treatment protected the photosynthetic performance of the leaves, primarily by maintaining the photosynthetic area, maximum photochemical efficiency, and photoprotective capacity (NPQ) of the infected leaves, thereby ensuring the supply of energy and carbon skeletons. Additionally, ARA treatment significantly enhanced the phenylalanine metabolic pathway, increasing the activity of key defense enzymes, including phenylalanine ammonia-lyase (PAL), chitinase (CHI), peroxidase (POD), and laccase (LAC). This drove the accumulation of disease resistance-related compounds such as lignin, coumarins, and flavonoids, thereby strengthening both physical and chemical barriers. Furthermore, ARA treatment reduced the accumulation of malondialdehyde (MDA), a product of membrane lipid peroxidation, and reducing sugars, indicating alleviated cellular oxidative damage and improved carbon metabolism balance. Metabolomic analysis further confirmed the critical role of phenylalanine metabolism. This study demonstrates that exogenous ARA application does not merely trigger an isolated response but initiates an integrated disease resistance program, coordinating multiple processes such as photosynthetic protection, cell wall reinforcement, and the accumulation of antimicrobial compounds. Based on the experimental results, we speculate that this systemically enhanced resistance may be closely associated with the activation of the salicylic acid signaling pathway. These findings not only provide a theoretical foundation for utilizing ARA as an eco-friendly plant resistance inducer to control WLS, but also offer novel biological insights into how endogenous signaling networks integrate multiple defense layers, thereby contributing to the advancement of sustainable agriculture. Exogenous arachidonic acid (ARA) induces resistance to white leaf spot in maize (WLS). The most significant effect of ARA at a concentration of 15 µM on WLS resistance. ARA significantly improved the photosynthetic performance of susceptible leaves. ARA significantly increased the activity of relevant defense enzymes in susceptible leaves. ARA may enhance disease resistance by mimicking or potentiating the salicylic acid (SA) signaling pathway.
Rhododendron jiucaipingensis Jian Xu & M. T. An, sp. nov . (Ericaceae), a new species of R. subgen. Hymenanthes , subsect. Argyrophylla , from northwestern Guizhou, China, is described and illustrated. It is an evergreen shrub 1.5–3.0 m tall, characterized by green, densely white-tomentose current-year branchlets, leaves crowded at branch apices (5.5–9.5 × 2.5–4.0 cm) with 8–11 pairs of lateral veins, 10 stamens, and cylindric capsules 1.2–2.0 cm long. The new species is morphologically most similar to R. hypoglaucum and R. argyrophyllum , but it is readily distinguished by having densely white-tomentose current-year branchlets, fewer lateral veins (8–11 pairs), a double-layered white indumentum on the abaxial surfaces of young leaves, and 10 stamens. Phylogenetic analysis based on a whole-genome SNP dataset robustly resolves R. jiucaipingensis as a distinct lineage within subsect. Argyrophylla , positioned as sister to the monophyletic clade of five congeneric species with high support (SH-aLRT = 100%, UFBoot = 100%). This molecular evidence, congruent with diagnostic morphological characters, supports the recognition of R. jiucaipingensis as a species new to science.
Guizhou Province is located in the hinterland of southwestern China and the eastern part of the Yunnan-Guizhou Plateau,with a unique ecological position and rich biodiversity.Its higher plant species diversity ranks fourth in China.Based on the Flora of Guizhou,related literature,and specialized surveys,this study systematically compiled data on the diversity of higher plants in Guizhou,covering information such as species names,distribution,and conservation status.Statistics were conducted according to administrative divisions and natural geographic regions,including the four major mountain ranges and eight major river systems of the province.As of April 30,2025,a total of 11,686 species and infraspecific taxa(including 9,921 species and 1,765 infraspecific taxa)of higher plants have been recorded in the province,belonging to 386 families and 2,396 genera.Among these,there are 10,967 species of wild higher plants in 373 families and 2,185 genera,547 endemic higher plant species in Guizhou,782 karst-obligate plant species,719 commonly introduced and cultivated plant species in 115 families and 402 genera,and 202 invasive higher plant species.The dataset also records 256 national key protected wild higher plant species and 55 provincial key protected wild higher plant species in Guizhou.In terms of spatial distribution,Qiannan Buyi and Miao Autonomous Prefecture(6,792 species)and Libo County(3,981 species)have the highest species richness among prefecture-level and county-level units,respectively.The Miaoling Mountains(6,340 species)and the Wujiang River System(8,732 species)are the regions with the highest species diversity among mountain ranges and river systems,respectively.These results provide important data for understanding the characteristics of higher plant diversity in Guizhou and for their conservation and utilization.They also offer a data support for the compilation of specialized works such as the Flora of Guizhou(second edition)and the Dendrology of Guizhou.
Background Research on the endangered mechanisms and conservation strategies of rare plants is one of the key tasks in plant biodiversity conservation. The southwestern region of China is a concentrated distribution area and endemic center for the family Gesneriaceae in China. The abundant rainfall and unique geological landforms have created unique habitats suitable for the survival of endemic species, nurturing many endemic species of high scientific value. This paper focuses on Oreocharis esquirolii (Gesneriaceae), an extremely narrowly distributed Chinese endemic plant in the broad sense of the genus Oreocharis, exploring the root-soil interaction mechanisms that maintain its population, identifying key factors that may have a significant impact on the species, maintenance, and providing a foundational basis for biodiversity conservation in Guizhou. Results The soil in the Lengshui River area where the O. esquirolii community is located is slightly acidic. The dominant bacterial genera in the soil samples are Bradyrhizobium and Paraburkholderia . The content of Fe 2 O 3 and SiO 2 in the minable coal seam compounds is 39.26% and 31.53%, respectively. The non-rhizosphere (b) soil samples show a higher abundance of energy metabolism pathways. The main gene functions in the soil samples are glutamine synthetase, carbonic anhydrase, and the large chain of glutamate synthase (NADPH). Among them, glutamine synthetase and glutamate synthase are the primary pathways for synthesizing glutamate when nitrogen is limited. Preliminary investigations indicate that Cirsium setosum uses its well-developed roots to attach to rock surfaces, where the soil is extremely thin. One possible way it obtains nutrients is through carbonic anhydrase. Carbonic anhydrase can act as a biocatalyst to accelerate the dissolution of limestone, allowing various elements in the limestone to be incorporated into the root soil and provide essential nutrients for the plant. Conclusions Investigating the metagenomics of rhizosphere and non-rhizosphere soils in the Cold Water River area of the Zhenfeng Longshan Protected Area, the only known distribution site of O. esquirolii , combined with the chemical composition of the soil layers, provides a reliable basis for the conservation of wild resources of O. esquirolii and the construction of its natural return sites.
This study elucidates the regulatory effects of Ageratina adenophora invasion on soil nutrient cycling, enzyme activities, and microbial composition/function in karst ecosystems of central Guizhou and reveals the plant–soil–microbe feedback-driven invasion loop. Four invasion gradients were established in Guanling County: CK (uninvaded), L (10–30% cover), M (30–60%), and H (60–90%). Soil nutrients, enzyme activities, metagenomic profiles, and nutrient contents in vegetative organs of A. adenophora and native Artemisia argyi were analysed. Key results: (1) Soil microbial communities included 7 domains, 198 phyla, 179 classes, 364 orders, 856 families, 3,531 genera, and 22,111 species. No significant differences were detected in soil nutrients, enzyme activities, or microbial composition/structure/diversity across invasion gradients. (2) Invaded soils presented significantly greater soil organic carbon (SOC), total nitrogen (TN), and pH than CK soils. Sucrase and urease activities were significantly elevated. Compared with A. argyi leaves, A. adenophora leaves contained significantly greater TN and total potassium (TK). (3) Microbial Shannon diversity ( H' ) and Pielou evenness ( J ) were significantly decreased. Verrucomicrobia and Candidatus Eisenbacteria were significantly enriched in invaded vs. CK soils. (4) Functional gene (K13038 and K00639) levels were significantly correlated with invasion intensity. Carbohydrate metabolism genes ( GT10 and CBM4) were upregulated by 1.5- and 1.7-fold, respectively; the stress resistance gene merG was upregulated 2.3-fold. These changes collectively demonstrate that A. adenophora invasion increases SOC/TN content and sucrase/urease activity, restructures microbial communities, and upregulates carbohydrate metabolism/stress resistance-related genes, establishing a self-reinforcing "invasive plant‒soil–microbe" feedback loop in karst ecosystems.
