The influence of root exudates on neighboring plants is one of the important factors determining the coexistence status of plants and their neighbors. This study aimed to explore the effects of the root exudates of Stylosanthes guianensis and cultivation substrates on the growth and physiological characteristics of Hevea brasiliensis seedlings. We cultivated H. brasiliensis seedlings with distilled water, sterilized vermiculite, and soil as cultivation substrates, and compared the differences in biomass accumulation and distribution, aboveground and underground morphological characteristics and physiological characteristics of H. brasiliensis when they respectively were irrigated with nutrient solutions containing the root exudates of S. guianensis and containing their own root exudates. The results showed that in soil culture and distilled water culture, the aboveground biomass, underground biomass, total biomass, primary lateral root number, chlorophyll content, carotenoid content, soluble carbohydrate content and root vitality of H. brasiliensis seedlings under the treatment of S. guianensis root exudates were significantly higher than those under the treatment of their own root exudate (P<0.05), except for the difference of root-shoot ratio, plant height and root length. Moreover, except for root vitality, the increase extent of the indexes was distilled water culture > soil culture. The malondialdehyde (MDA) content of S. guianensis root exudate treatment was significantly lower than that of H. brasiliensis root exudate treatment (P<0.05). When cultured with sterilized vermiculite, there were no significant differences in biomass index, morphological index and MDA content of H. brasiliensis seedlings treated with root exudates of two kinds of plants, but chlorophyll content, carotenoid content, soluble sugar content, and root vitality were significantly increased under root exudates of S. guianensis treatment (P<0.05). The comprehensive evaluation of membership function of H. brasiliensis seedlings cultivated in the substrates under the treatment of root exudates of S. guianensis was higher than that of their own root exudates, and the comprehensive evaluation of cultivation substrates under the treatment of the same root exudates was vermiculite culture > distilled water culture > soil culture. It indicates that the root exudates of S. guianensis can significantly improve the physiological function of H. brasiliensis seedlings and promote their growth, but the response of H. brasiliensiss to root exudates is significantly affected by the cultivation substrate.

The study was aimed to explore the photosynthetic characteristics and yield underground corm of Amorphophallus muelleri under different light conditions. Three intercrop modes of A. muelleri, pruned rubber tree intercrop mode T₁ [forest center (T_1M) and forest edge (T_1S)], interrow mode of puelia T₂[forest center (T_2M) and edge (T_2S)], 50% light transmittance shade mode T_3M, no pruning rubber tree (CK)[forest center (CK_M) and edge (CK_S)] were used. The light intensity (Lux) and photosynthetically active radiation (PAR) in different light conditions were measured. The daily variation pattern of A. muelleri, photosynthetic parameters [net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular carbon dioxide concentration (C_i), transpiration rate (T_r)], chlorophyll fluorescence parameters [maximum photochemical efficiency (F_v/F_m), actual photochemical quantum yield(YII), maximum electron transfer rate (ETR_max), half-saturation light intensity (Ik)], photosynthetic pigment parameters [chlorophyll a (Chl a), chlorophyll b(Chl b), total chlorophyll (Chl a+b), chlorophyll a/b (Chl a/b)] were measured at three stages (head changing stage, corm expansion stage, maturity stage). The yield of underground corm under different light conditions was compared. The results showed that daily variations of Lux and PAR were basically consistent under light conditions, showing “unimodal”modes. There were significant differences in the photosynthetic parameters (P_n, G_s, T_r, and C_i) among different light conditions. Compared with CK, P_n, G_s, and T_r of the T_3M were the significantly highest in all three stages. During the head changing and corm expansion stages, P_n, G_s, T_r of the T₁ and T₂ were significantly higher than those of CK; The chlorophyll fluorescence parameters (F_v/F_m, YII, ETR_max, IK) of each light conditions were significantly higher than those of CK; The changes in photosynthetic pigment parameters (Chl a, Chl b, Chl a+b, Chl a/b) of various conditions were irregular. The Chl a, Chl b, Chl a+b of T₂ and CK were higher than those of T₁ and T₃ at all three stages, and Chl a/b of all treatments was significantly higher than those of CK. From the comparison of light intensity and yield between the forest center and edge under conditions, it can be seen that the forest center is higher than the forest edge. After comparing the implementation effects of various intercropping modes, it can be seen that all treatments have improved the photosynthetic characteristics and yield of A. muelleri, while the pruned rubber tree modes T₁ treatment is most obvious, and achieved the similar effect of single cropping under artificial shade. Therefore, in rubber tree production, pruning measures or other measures is needed to improve the light conditions and replace monoculture artificial shade for planting A. muelleri. The intercrop mode of puelia requires increase in fertilizer application and a reasonable allocation of crop distance direction to effectively alleviate the burns caused by direct sunlight on A. muelleri plants, and improve photosynthetic efficiency, thereby increasing crop yield and land use efficiency.

Cassava (Manihot esculenta Crantz), the “king of starch”, is an important tropical food crop and a staple food for one billion people worldwide. Cassava vacuolar invertase (MeVINV1) is involved in plant growth and development and stress defense by irreversibly breaking down sucrose into glucose and fructose. Eight candidate proteins interacting with MeVINV1 were screened from the cassava SC8 cDNA yeast library by yeast two-hybrid experiment to explore the gene function and molecular regulatory network of MeVINV1. Furthermore, yeast point-to-point verification found that MeVINV1 interacted with MeUN-3, MeMTP1, MeCASP4A3 and MePIRL3, and the interaction with MeMTP1 was stronger. Therefore, it is speculated that MeVINV1 and MeMTP1 synergistically regulate vacuolar sucrose metabolism and metal ion transport, and participate in the regulation of cassava response to metal ion stress. The results of the study would provide a scientific basis for providing new genetic resources and molecular mechanisms of stress regulation in cassava stress resistance breeding.

After intercropping pepper with areca nut, pepper plants recovered their growth. This might be related to the mutual interaction between the rhizospheres of the two plants, especially the promoting effect of areca nut root exudates on pepper plants. However, the specific components that play a role remain unclear, which makes it difficult to provide a basis for in-depth research. In this study, the root exudates of pepper and areca nut seedlings were extracted by hydroponics. The full components of the root exudates were identified by LC-MS/MS metabolomics, and the specific differential components unique to areca nut root exudates were screened out. After classification, these were used as the exogenous substances and added to further clarify the effects of different components on pepper seed germination and seedling growth. A total of 426 metabolites were detected in the root exudates of pepper, and 438 metabolites were identified in those of areca nut. There were 509 differential metabolites between areca nut and pepper, among which 329 were significantly different, and 138 were more abundant in areca nut and 191 in pepper. The contents of flavonoids and organic acids were higher in areca nut root exudates than those in pepper, while the contents of sugars, phenolic acids, coumarins, benzoic acids and amino acids were higher in pepper than in areca nut. After classification of the differential metabolites with high content in areca nut root exudates into organic acids, amino acids, phenolic acids, sugars and flavonoids, two with higher fold differences were selected as specific components for addition. The results showed that the addition of flavonoids had the highest germination rate and germination potential of pepper seeds, and the height of seedlings, dry weight of aboveground and underground parts were the highest. The addition of organic acids and phenolic acids was second, while the effects of sugars and amino acids were not obvious. In conclusion, there are many specific differential components in areca nut root exudates, but the promoting effects of different components on the growth of pepper seedlings in soil culture after intercropping are different. Among them, the flavonoids group has a large number and high content, and has obvious promoting effects on pepper seed germination and seedling growth, which is the main component of areca nut root exudates that alleviates the disorder of pepper intercropping. The results of this study provides a basis and theoretical evidence for revealing the mechanism of rhizosphere interaction between the two plants and analyzing the alleviation of pepper intercropping disorder by intercropping with areca nut.

In order to investigate the biocontrol ability and mechanism of Burkholderia GXMZU-5 with quorum quenching activity, the biocontrol effect was verified through experiments on bacterial soft rot of banana fruits and potted seedlings (Dickeya zeae GR-1), and the biocontrol mechanism was verified by measuring the content of biofilm, the ability to remove extracellular polysaccharides, the ability to inhibit the metabolic activity of biofilm, and PCR amplification of QQ enzyme homologous genes. The results showed that GXMZU-5 could effectively degrade acylhomoserine lactone (AHLs) signal molecules and had AHLs quenching ability. In the biocontrol experiment on banana fruits, the surface of the mixed bacteria experimental group was healthier than that of the control group, with no obvious black spots or soft rot signs. The cross-section and longitudinal section results of banana fruits showed that the lesion area of the treatment group was significantly reduced. In the potted plant control experiment, there were no obvious signs of rot at the injection site of the mixed bacteria group, and the natural plant height recovered by 56% compared with the pathogen group, indicating that GXMZU-5 had a significant inhibitory effect on the disease caused by Dickeya zeae GR-1. The results for exploring of the biocontrol mechanism showed that the total content of biofilm and the content of extracellular polysaccharides in the mixed bacteria system were lower than those of the two bacteria cultured separately. The MTT method for measuring biofilm metabolism indicated that GXMZU-5 could effectively reduce the biofilm metabolic activity of Dickeya zeae GR-1 and occupied a dominant position in the mixed bacteria system. The exploration of the biocontrol mechanism indicated that GXMZU-5 could reduce the biomass and vitality of Dickeya zeae GR-1 biofilm through quenching effect, thereby obtaining biocontrol ability. The amplification of QQ enzyme homologous genes showed that GXMZU-5 had the aiiA lactonase gene and could quench AHLs signal molecules. This study verified the biocontrol ability of GXMZU-5 and preliminarily explored its biocontrol mechanism, providing a certain reference basis for the use of quenching bacteria to control plant bacterial diseases.

Isoamylase (Isoamylase, ISA) catalyzes the hydrolysis of α-1,6 linkages, thereby affecting the branching structure of starch and promoting crystallization and granule formation. The study utilized yeast two-hybrid screening to identify proteins interacting with MeISA2 to explore new proteins that may interact with MeISA2 to influence cassava starch accumulation. A bait protein vector pGBKT7-MeISA2 was constructed, and it was demonstrated that MeISA2 did not possess autoactivation activity and was non-toxic to yeast cells. Through yeast two-hybrid screening of a cDNA library, a total of 7 candidate interacting proteins were obtained. Point-to-point yeast two-hybrid re-validation experiments confirmed the interaction between MeISA2 and MePsbO1. MePsbO1 belongs to the Photosystem II oxygen-evolving enhancer protein (PsbO) family, which facilitates the efficient operation of the photosynthetic electron transfer process. Bioinformatics analysis revealed that MePsbO1 had the closest phylogenetic relationship with HbPsbO1 from Hevea brasiliensis, a member of the Euphorbiaceae family, with a similarity of 90.12%, while its similarity to Arabidopsis thaliana AtPsbO1 was only 77.71%. It is predicted that MePsbO1 is localized in the chloroplast, and the MePsbO1 gene is predominantly expressed in leaves. Plant ISA is involved in the synthesis of transient leaf starch, thus it is hypothesized that MePsbO1 and MeISA2 may interact to jointly regulate the rate of photosynthesis and the accumulation of transient leaf starch. The results study would provide new insights into the mechanism by which the MeISA2 gene participates in the accumulation and distribution of photosynthetic products in cassava source organs.

Stylosanthes guianensis, Pueraria phaseoloides, and Tephrosia candida were selected to investigate the impact mechanisms of green manures on soil physicochemical properties and nitrogen content in rubber tree leaves, through the analysis of natural abundance of ¹⁵N (δ¹⁵N) and partial least squares path analysis (PLS-PM) to elucidate the effects of different leguminous green manures on soil improvement and nitrogen uptake in young rubber plantations. Results showed that P. phaseoloides and S.guianensis treatments significantly increased soil alkaline nitrogen by 30.54% and 31.25%, respectively, while reducing available potassium by 8.40% and 6.87%, compared to natural grass cover. P. phaseoloides treatment had the strongest effect on increasing soil organic matter and available phosphorus content, with increases of 12.60% and 30.94%, respectively. S. guianensis treatment had the strongest effect on increasing the total nitrogen content in rubber trees leaves (an increase of 25.86%). Correlation analysis and PLS-PM indicated a significant positive correlation between leguminous green manures and soil alkaline nitrogen and total nitrogen content, with a significant positive effect. In conclusion, under the conditions of this study, leguminous green manures promoted the absorption and accumulation of nitrogen in rubber tree leaves by increasing soil alkaline nitrogen content. The rational selection or mixed planting of leguminous green manures can improve the nutrient absorption efficiency of rubber trees and contribute to the sustainable production of rubber plantations.

Nymphaea prolifera has a peculiar and unusual asexual reproductive mechanism called floral “vegetative viviparity” which allows it to produce new seedlings directly from its flowers. Understanding the formation process of floral vegetative viviparity and the effect of endogenous hormones on its formation will provide a basis for further elucidating the mechanism of vegetative viviparity in N. prolifera and the biology of asexual plant reproduction. Morphological observation, paraffin sectioning and scanning electron microscopy were used to analyse the morphological characteristics of vegetative viviparity flowers of N. prolifera as the test group and normal flowers as the control group. Elisa assay was used to compare the deviation in endogenous hormones between “nutrient propagules” from vegetative viviparity flowers and pistils from normal flowers. Nutrient propagules were formed on the receptacle in the original pistil area and are already formed at the stage of flower bud differentiation. In contrast to the flowers of normally developing water lilies, vegetative viviparity flowers only retained receptacle, sepals, and other organs; they lack petals, stamens, and pistils. Then, the nutrition propagules could continually develop leaf and flower buds. The leaf buds were mostly triangular and curled, while the flower buds were mostly hooked or conical and had many ciliated tissues on the surface. A vegetative viviparity growing flower's nutritional propagules could give rise to several asexually reproducing buds, which could then proceed to reproduce in a second and third generation once they reached a particular stage of development. Endogenous hormone assays showed that indoleacetic acid (IAA) and gibberellin (GA) levels were not significantly different between normal and vegetative viviparity water lily flower nutrient propagules, whereas jasmonic acid (JA), cytokinin (CTK) and abscisic acid (ABA) levels were systematically higher in vegetative viviparity water lily flower trophozoites. Vegetative viviparity flowers of N. prolifera had obvious differences in tissue structure compared to normal flowers. During flower bud differentiation, the gynoecium of N. prolifera flowers was replaced by the nutritive propagules to form vegetative viviparity flowers. Compared with those of the gynoecium of normal flowers, three endogenous hormones such as jasmonic acid (JA), cytokinin (CTK) and abscisic acid (ABA) levels were consistently higher in the nutritive propagules of vegetative viviparity flowers, which may contribute to the formation of the floral vegetative viviparity phenomenon.

Atg26 (or Ugt51) is a UDP-glucose: sterol glucosyltransferase, which regulates the biological process of sterol conversion to sterol glucoside (SG), participates in various cellular autophagy processes, and plays an important role in fungal growth, development and pathogenicity. In order to investigate the role of Atg26 in the growth, development and virulence of Peronophythora litchii, six Atg26 homologous proteins were identified through bioinformatics. The analysis of protein properties showed that the secondary structure of the protein was mainly random curling and had hydrophilic properties. The results of gene and protein structure analysis showed that except PlATG26a, the other ATG26 homologous genes of P. litchii had introns, which were mostly distributed at the end of the gene. All Atg26 homologous proteins contained the CAT catalytic domain, but did not have the PH (pleckstrin homology) and GRAM (glucosyltransferase, Rab-like GTPase activators, and myotubularins) domains that make up the PBD (phosphoinositide binding domain). Further phylogenetic and conserved motif analysis of Atg26 homologous proteins found that diversity existed among the Atg26 homologous proteins in P. litchii, but the CAT domain of Atg26 was conserved in different species. Protein interaction prediction and protein molecular docking analysis showed that the interacting proteins of PlAtg26 were mostly located in the cytoplasm or membrane, concentrated in the process of cell metabolism, and had catalytic activity, REDOX activity or binding ability, which also indicated that PlAtg26 may not require the binding ability of GRAM domain for localization. Quantitative real-time PCR (qRT-PCR) analysis showed that PlATG26b was up-regulated in zoospore stage and early infection, but had no significant difference in sporangium stage and late infection. This result also indicated that Atg26 played an important role in the asexual reproduction and infection of P. litchii. In conclusion, PlAtg26 and Atg26 homologues in fungi have significant structural differences and may show different biological functions from fungi.

Red fire ant, Solenopsis invicta, a serious invasive pest native to South America, has been widely distributed in China, posing significant threats to agriculture, natural ecosystems, and public health. Effective entry-exit quarantine measures are essential to prevent the invasion and spread of S. invicta, which requires rapid and accurate identification of the pest. Existing detection methods, including morphological identification, DNA barcoding, immunoassay, and loop-mediated isothermal amplification (LAMP) have limitations in simplicity, detection speed and sensitivity. Recombinase polymerase amplification (RPA) is an isothermal amplification technique characterized by its simplicity, high sensitivity, and efficient amplification. To enable rapid and accurate on-site detection of S. invicta, this study developed a visual detection method based on RPA technology. Mitochondrial genome sequences of S. invicta and closely related or morphologically similar species were analyzed using data from the NCBI database. The mitochondrial NADH₂ dehydrogenase gene was selected as the target for amplification, and specific RPA primers were designed. Experimental results confirmed that the primers demonstrated high specificity for S. invicta. Sensitivity testing using agarose gel electrophoresis revealed that the RPA reaction could detect as low as 1.0×10^-4 ng/μL, which is 10³ times more sensitive than conventional PCR. A visual detection method was further developed by incorporating nucleic acid dyes into the reaction, achieving a sensitivity of approximately 1.0×10^-1 ng/μL. Additionally, a rapid DNA extraction method was explored. This method involved grinding ant samples in sterile water followed by heating at 100 ℃ in a water bath for one minute, which successfully yielding crude DNA. The developed method enables gene amplification of S. invicta at 37 ℃, with detection results assessed via fluorescence reactions, completing the entire process within 30 minutes. This approach provides a convenient, rapid, accurate, and reliable technical method for detecting S. invicta, offering valuable technical support for its quarantine, prevention and control.