Secretion Of Secondary Metabolites Research Articles

A Highly Efficient System for Separating Glandular and Non-glandular Trichome of Cucumber Fruit for Transcriptomic and Metabolomic Analysis.

Cucumber (Cucumis sativus) trichomes play a critical role in resisting external biological and abiotic stresses. Glandular trichomes are particularly significant as they serve as sites for the synthesis and secretion of secondary metabolites, while non-glandular trichomes are pivotal for determining the appearance quality of cucumbers. However, current methods for separating trichomes encounter challenges such as low efficiency and insufficient accuracy, limiting their applicability in multi-omics sequencing studies. This protocol introduces an efficient system designed for the precise separation of glandular and non-glandular trichomes from cucumber fruit. The process begins with the pre-cooling of sorbitol buffer or ethanol solution and the RNA-free treatment of laboratory supplies, followed by sterilization and pre-cooling. After filling glass bottles with pre-cooling buffer and glass beads, cucumber ovaries are then placed in the glass bottles and the trichome is harvested by bead-beating method. The separation process involves sequential filtration through various steel sieves and centrifugation to separate trichomes. The separated trichomes obtained from this method are well-suited for subsequent multi-omics sequencing analyses. This protocol achieved high precision in separating glandular and non-glandular trichomes, significantly enhancing the efficiency of separation and sample collection processes. This advancement not only addresses existing limitations but also facilitates comprehensive studies aimed at exploring the genetic and biochemical diversity present within cucumber trichomes, thereby opening avenues for broader agricultural and biological research applications. Key features • Use cucumber fruits on the day of flowering. • Pre-cooling and RNA-free treatment ensure supply quality and purity. • Efficiently separate glandular and non-glandular trichomes. • Trichome samples are suitable for multi-omics sequencing analysis.

Composition and functional diversity of soil and water microbial communities in the rice-crab symbiosis system.

Rice-crab co-culture is an environmentally friendly agricultural and aquaculture technology with high economic and ecological value. In order to clarify the structure and function of soil and water microbial communities in the rice-crab symbiosis system, the standard rice-crab field with a ring groove was used as the research object. High-throughput sequencing was performed with rice field water samples to analyze the species and abundance differences of soil bacteria and fungi. The results showed that the OTU richness and community diversity in soil were significantly higher than those in water, while there were significant differences in soil microbial diversity and OTU richness in water sediments. The dominant species at the bacterial phylum level were Amoebacteria, Cyanobacteria, Actinomycetes, Synechococcus and Greenbacteria, and at the genus level the dominant species were norank_f_norank_o_Chloroplast, unclassified_f_Rhodobacteraceae, LD29, Cyanobium_PCC-6307, and norank_f_MWH-UniP1_aquatic_group. The dominant species at the fungal phylum level are unclassified_k_Fungi, Ascomycota, Rozellomycota, Phaeomycota and Stenotrophomonas, and at the genus level the dominant species are unclassified_k_Fungi, unclassified_p_Rozellomycota, Metschnikowia, Cladosporium, unclassified_p_Chytridiomycota. The dominant phylum may rely on mechanisms such as organic matter catabolism, secretion of secondary metabolites and phototrophic autotrophy, as predicted by functional gene analysis. The main functional genes are related to metabolic functions, including secondary product metabolism, energy metabolism, and amino acid metabolism.

Potential application of a fungal co-culture crude extract for the conservation of post-harvest fruits.

Fungal plant pathogens are responsible for serious losses in many economically important crop species worldwide. Due to the use of fungicides and the fungi genome plasticity, multi-drug resistant strains are emerging as a new generation of pathogens, causing an expansive range of superficial and systemic plant infections, or new opportunistic fungal pathogens for humans. The group of antagonistic fungi Trichoderma spp. has been widely used to enhance plant growth and for the control of different pathogens affecting crops. Although Neurospora crassa is not a mycoparasitic fungus, its secretion of secondary metabolites with antimicrobial activity has been described. In this work, the effect of crude extract of the monoculture of Trichoderma asperellum T8a or the co-culture with N. crassa as an inhibitory treatment against the fungal pathogens Botrytis cinerea and Fusarium solani was evaluated. The findings demonstrate that the secondary metabolites contained in the T. asperellum crude extract have a clear fungistatic activity against B. cinerea and F. solani. Interestingly, this fungistatic activity highly increases when T. asperellum is co-cultivated with the non-pathogenic fungus N. crassa. Moreover, the co-culture crude extract also showed antifungal activity on post-harvest fruits, and no toxic effects on Murine fibroblast L929 (CCL-1) and murine macrophages RAW 264.7 (TIB-71) were observed. All these results together are solid evidence of the potential of the co-culture crude extract of T. asperellum and N. crassa, as an antifungal agent against phytopathogenic fungi, or post-harvest fruits during the transportation or commercialization time.

Glandular trichomes of medicinal plants: types, separation and purification, biological activities

Glandular trichomes (GTs) are one of the epidermal tissues of medicinal plants which function in the synthesis, storage, and secretion of secondary metabolites. The active ingredients of Chinese medicinal materials are mostly secondary metabolites of plants. Accordingly, it is of great research value to explore the quality of medicinal materials using the GTs of medicinal plants as the starting point. However, most of the current studies on GTs of medicinal plants are still at the simple morphological identification stage, and there are few studies on the compounds secreted by GTs and secondary metabolic processes. Here, we reviewed the literature, summarized the morphological types of medicinal plant GTs, separation and purification technology, analysis technology, and biological activities of secondary metabolites, and established a research approach to medicinal plant GTs. We hope to provide a reference for future research on GT inclusions and secondary metabolism.

Genome Analysis of the Broad Host Range Necrotroph Nalanthamala psidii Highlights Genes Associated With Virulence.

Guava wilt disease is caused by the fungus Nalanthamala psidii. The wilt disease results in large-scale destruction of orchards in South Africa, Taiwan, and several Southeast Asian countries. De novo assembly, annotation, and in-depth analysis of the N. psidii genome were carried out to facilitate the identification of characteristics associated with pathogenicity and pathogen evolution. The predicted secretome revealed a range of CAZymes, proteases, lipases and peroxidases associated with plant cell wall degradation, nutrient acquisition, and disease development. Further analysis of the N. psidii carbohydrate-active enzyme profile exposed the broad-spectrum necrotrophic lifestyle of the pathogen, which was corroborated by the identification of putative effectors and secondary metabolites with the potential to induce tissue necrosis and cell surface-dependent immune responses. Putative regulatory proteins including transcription factors and kinases were identified in addition to transporters potentially involved in the secretion of secondary metabolites. Transporters identified included important ABC and MFS transporters involved in the efflux of fungicides. Analysis of the repetitive landscape and the detection of mechanisms linked to reproduction such as het and mating genes rendered insights into the biological complexity and evolutionary potential of N. psidii as guava pathogen. Hence, the assembly and annotation of the N. psidii genome provided a valuable platform to explore the pathogenic potential and necrotrophic lifestyle of the guava wilt pathogen.

Bacterial diversity evolution process based on physicochemical characteristics of sludge treating hydroquinone during acclimation.

Hydroquinone is one of the main pollutants in coal-gasification wastewater, which is biologically toxic and difficult to remove. The aerobic biodegradation rate, organic toxicity, and microbial community structure at different acclimation stages of degradation of hydroquinone by activated sludge were investigated. In each acclimation cycle, the removal of hydroquinone reached 100% after 5 days, indicating that high-concentration hydroquinone in the activated sludge could be completely biodegraded. When the microbial flora was inhibited by the influent hydroquinone, the enzyme system experienced stress conditions and led to the secretion of secondary metabolites, extracellular protein of 5-10 kDa mainly contributing to the sludge organic toxicity. Microbial diversity analysis showed that with the increase of the concentration of hydroquinone, β-Proteus bacteria such as Azoarcus and Dechloromonas gradually accumulated, which improved the removal of hydroquinone with aerobic activated sludge in the sequencing batch reactor (SBR) system. As the inhibition degree exceeded the appropriate tolerance range of microorganisms, bacteria would secrete much more secondary metabolites, and the organic toxicity of sludge would reach a relatively high level.

Comparative Genomics of Novel Agrobacterium G3 Strains Isolated From the International Space Station and Description of Agrobacterium tomkonis sp. nov.

Strains of Agrobacterium genomospecies 3 (i.e., genomovar G3 of the Agrobacterium tumefaciens species complex) have been previously isolated from diverse environments, including in association with plant roots, with algae, as part of a lignocellulose degrading community, from a hospital environment, as a human opportunistic pathogen, or as reported in this study, from a surface within the International Space Station. Polyphasic taxonomic methods revealed the relationship of Agrobacterium G3 strains to other Agrobacterium spp., which supports the description of a novel species. The G3 strains tested (n = 9) were phenotypically distinguishable among the strains from other genomospecies of the genus Agrobacterium. Phylogenetic analyses of the 16S rRNA gene, gyrB gene, multi-locus sequence analysis, and 1,089-gene core-genome gene concatenate concur that tested G3 strains belong to the Agrobacterium genus and they form a clade distinct from other validly described Agrobacterium species. The distinctiveness of this clade was confirmed by average nucleotide identity (ANI) and in silico digital DNA–DNA hybridization (dDDH) comparisons between the G3 tested strains and all known Agrobacterium species type strains, since obtained values were considerably below the 95% (ANI) and 70% (dDDH) thresholds used for the species delineation. According to the core-genome phylogeny and ANI comparisons, the closest relatives of G3 strains were Agrobacterium sp. strains UGM030330-04 and K599, members of a novel genomospecies we propose to call genomovar G21. Using this polyphasic approach, we characterized the phenotypic and genotypic synapomorphies of Agrobacterium G3, showing it is a bona fide bacterial species, well separated from previously named Agrobacterium species or other recognized genomic species. We thus propose the name Agrobacterium tomkonis for this species previously referred to as Agrobacterium genomospecies 3. The type strain of A. tomkonis is IIF1SW-B1T (= LMG 32164 = NRRL B-65602). Comparative genomic analysis show A. tomkonis strains have species-specific genes associated with secretion of secondary metabolites, including an exopolysaccharide and putative adhesins and resistance to copper. A. tomkonis specific gene functions notably relate to surface adhesion and could be involved to colonize nutrient-poor and harsh habitats. The A. tomkonis strains from the ISS showed presence of a 40-kbp plasmid and several other potential mobile genetic elements detected that could also be part of conjugative elements or integrated prophages.

Ecological and Industrial Implications of Dynamic Seaweed-Associated Microbiota Interactions.

Seaweeds are broadly distributed and represent an important source of secondary metabolites (e.g., halogenated compounds, polyphenols) eliciting various pharmacological activities and playing a relevant ecological role in the anti-epibiosis. Importantly, host (as known as basibiont such as algae)–microbe (as known as epibiont such as bacteria) interaction (as known as halobiont) is a driving force for coevolution in the marine environment. Nevertheless, halobionts may be fundamental (harmless) or detrimental (harmful) to the functioning of the host. In addition to biotic factors, abiotic factors (e.g., pH, salinity, temperature, nutrients) regulate halobionts. Spatiotemporal and functional exploration of such dynamic interactions appear crucial. Indeed, environmental stress in a constantly changing ocean may disturb complex mutualistic relations, through mechanisms involving host chemical defense strategies (e.g., secretion of secondary metabolites and antifouling chemicals by quorum sensing). It is worth mentioning that many of bioactive compounds, such as terpenoids, previously attributed to macroalgae are in fact produced or metabolized by their associated microorganisms (e.g., bacteria, fungi, viruses, parasites). Eventually, recent metagenomics analyses suggest that microbes may have acquired seaweed associated genes because of increased seaweed in diets. This article retrospectively reviews pertinent studies on the spatiotemporal and functional seaweed-associated microbiota interactions which can lead to the production of bioactive compounds with high antifouling, theranostic, and biotechnological potential.

Effect of Jasmonic Acid and Salicylic Acid on Growth and Biochemical Composition of In-Vitro-Propagated Lavandula angustifolia Mill

This study assessed the effect of jasmonic acid (JA) and salicylic acid (SA) on the in vitro development and production of Lavandula angustifolia Mill. plant material, and the accumulation of polyphenols, chlorophylls, and carotenoids in explants. Results were compared with explants grown in control media and with in-vivo-grown mature and young L. angustifolia plants. After 21 days of incubation, all explants propagated on low-SA-concentration or elicitor-free media produced a greater number of shoots than explants cultivated on media with higher elicitor concentrations. Shoots grew taller when activated charcoal (AC) was added to the elicitor-supplemented media, while AC negatively affected or had no effect on the phytochemical composition of plants. Explants grown in the presence of elicitors had higher polyphenolic and chlorophyll content than the controls, demonstrating the beneficial impact of elicitors on the secretion of secondary metabolites. Lutein and β-carotene were the dominating carotenoids in all samples. Culture media supplemented with 0.5 mg/L JA and 1.5 mg/L SA + AC proved the most suitable to produce plant material with high polyphenol and carotenoid content, comparable with in-vivo-grown plants.

An Updated Review of Secondary Metabolites from Marine Fungi.

Marine fungi are valuable and richest sources of novel natural products for medicinal and pharmaceutical industries. Nutrient depletion, competition or any other type of metabolic stress which limits marine fungal growth promotes the formation and secretion of secondary metabolites. Generally secondary metabolites can be produced by many different metabolic pathways and include antibiotics, cytotoxic and cyto-stimulatory compounds. Marine fungi produce many different types of secondary metabolites that are of commercial importance. This review paper deals with around 187 novel compounds and 212 other known compounds with anticancer and antibacterial activities with a special focus on the period from 2011-2019. Furthermore, this review highlights the sources of organisms, chemical classes and biological activities (anticancer and antibacterial) of metabolites, that were isolated and structurally elucidated from marine fungi to throw a helping hand for novel drug development.

Two FtsH Proteases Contribute to Fitness and Adaptation of Pseudomonas aeruginosa Clone C Strains.

Pseudomonas aeruginosa is an environmental bacterium and a nosocomial pathogen with clone C one of the most prevalent clonal groups. The P. aeruginosa clone C specific genomic island PACGI-1 harbors a xenolog of ftsH encoding a functionally diverse membrane-spanning ATP-dependent metalloprotease on the core genome. In the aquatic isolate P. aeruginosa SG17M, the core genome copy ftsH1 significantly affects growth and dominantly mediates a broad range of phenotypes, such as secretion of secondary metabolites, swimming and twitching motility and resistance to aminoglycosides, while the PACGI-1 xenolog ftsH2 backs up the phenotypes in the ftsH1 mutant background. The two proteins, with conserved motifs for disaggregase and protease activity present in FtsH1 and FtsH2, have the ability to form homo- and hetero-oligomers with ftsH2 distinctively expressed in the late stationary phase of growth. However, mainly FtsH1 degrades a major substrate, the heat shock transcription factor RpoH. Pull-down experiments with substrate trap-variants inactive in proteolytic activity indicate both FtsH1 and FtsH2 to interact with the inhibitory protein HflC, while the phenazine biosynthesis protein PhzC was identified as a substrate of FtsH1. In summary, as an exception in P. aeruginosa, clone C harbors two copies of the ftsH metallo-protease, which cumulatively are required for the expression of a diversity of phenotypes.

Nature Abhors a Vacuum: Highly Diverse Mechanisms Enable Spoilage Fungi to Disperse, Survive, and Propagate in Commercially Processed and Preserved Foods

Fungal spoilage in processed foods remains a challenge for food manufacturers despite the increasing availability of diverse processing and formulation strategies used to control foodborne microorganisms. Physiological features of yeasts and molds contribute to their tolerance to thermal processing, acidity, desiccation, and oxygen and nutrient limitations. These features variably include growth form, cell wall structure, cytoplasmic composition, cell membrane-bound proteins, and secretion of secondary metabolites. Collectively, these mechanisms contribute to the ability of fungi to disperse, survive, and propagate in highly restrictive food environments. The diversity of fungal growth and survival mechanisms has resulted in organisms adapted to nearly all food environments; although, only a small subset of fungi are particularly suited for spoilage of a given product. The relationship between the individual physiology and metabolic capabilities of a yeast or mold and the product's specific physicochemical attributes and processing history determines spoilage potential. Explicit characterization of the fungal features responsible for this extremotolerance contributes to more targeted and effective control strategies.

Secretory structures in the leaves of Hibiscus sabdariffa L.

Hibiscus sabdariffa (Roselle) is an economically important crop cultivated in parts of Asia and Africa. The leaves are consumed as a vegetable, whereas the calyces are used in a variety of different beverages. Leaves of H.sabdariffa have been studied for their anticancer and cholesterol-lowering effects, though very little is known with regard to the compounds produced in the leaves and how these are synthesized. Here, we provide an anatomical overview of the foliar secretory structures present and discuss some of the cellular mechanics involved in the secretion of secondary metabolites. The micromorphology of the external leaf surfaces and internal secretory structures were examined. The leaves of H.sabdariffa, though glabrous to the naked eye, are covered with glandular capitate trichomes. Using ultrastructural techniques, a subcuticular space was identified on the lower surface of the trichome, which compartmentalized and stored secreted substances until release onto the leaf surface. The function of the secretions observed are still yet unknown, however due to the presence of phenolics and alkaloids within trichomes determined using histochemical methods, they may serve as herbivore deterrents. Mucilage accumulating cells, also known as mucilage idioblasts were also encountered during the anatomical investigations and were characterized using light and electron microscopy. These findings have implications in the taxonomical classification of Hibiscus, and furthers research on this valued medicinal plant and the potential sources of useful phytometabolites within it.

Pathogenesis of Invasive Pulmonary Aspergillosis in Transplant Recipients

Transplant patients are at high risk for invasive pulmonary aspergillosis, and the associated mortality is high. The purpose of this study is to review the pathogenesis of invasive pulmonary aspergillosis (IPA) in transplant patients. The pathogenesis of aspergillosis is multifactorial and results from a complex interplay between the pathogen and host. It is well recognized that Aspergillus causes IPA in immunocompromised patients. Recent studies have shown that Aspergillus might also cause diseases likely attributed to an unmodulated immune response in certain transplant recipients such as bronchopulmonary aspergillosis or bronchiolitis obliterans syndrome in lung transplant recipients. This review focuses on two crucial axes of the damage response framework applicable to aspergillosis: (1) Aspergillus virulence attributes that enable it to survive and proliferate in the host (thermotolerance, stress and hypoxic response, secretion of secondary metabolites) and (2) host response with specific focus on innate immunity and angiogenesis.

Biological Interactions of Endophytic Fungi and their Applications in Various Fields

Endophytic fungi arenaturally adapted to within the tissue of the plants without harmful effect to the host plants. It protects the host plants through secretion of secondary metabolites under the stress condition. Endophytic fungi are asymbiotic association. Hence, biological interaction is also useful to the human beings due to this interaction create the novelty to explore the biotechnological applications in field of pharmaceutics, agricultures and industries Therefore, further research to understanding the mechanism of interaction involved between endophytic fungi and plants is needed.

In vitro interaction of Metarhizium anisopliae Ma9236 and Beauveria bassiana Bb9205 with Heterorhabditis bacteriophora HNI0100 for the control of Plutella xylostella.

The diamondback moth (Plutella xylostella) is a major pest of broccoli crops in Colombia. To control P. xylostella, we evaluated the interaction of Beauveria bassiana Bb9205 and Metarhizium anisopliae Ma9236 with Heterorhabditis bacteriophora HNI0100 and its bacterial symbiont Photorhabdus luminescens HNI0100. We used antagonism and disk diffusion assays with fungal extracts to test the interaction between symbiotic bacterium and fungi. P. luminescens inhibited the growth of B. bassiana and M. anisopliae up to 40% by the secretion of secondary metabolites, whereas fungal extracts did not inhibit P. luminescens; this explains the in vivo interactions of these biological control agents. To test the interaction between fungi and nematodes, we first inoculated the fungi followed by the nematodes on different days (0, 2, 4, and 6). We identified the type of interaction using the formula by Nishimatsu and Jackson (J Econ Entomol 91:410–418, 1998) and established that on days 0, 2 and 4 there was an antagonistic interaction, while a synergistic interaction occurred on day 6. Therefore, the use of the interaction between H. bacteriophora HNI0100 with M. anisopliae Ma9236 and B. bassiana Bb9205 is an innovative alternative for the control of P. xylostella.

Bacterial antagonists and hexanal-induced systemic resistance of mango fruits against Lasiodiplodia theobromae causing stem-end rot

ABSTRACTInduction of defense-related enzymes, such as phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenol oxidase (PPO), superoxide dismutase (SOD) and catalase (CAT) due to bacterial antagonists viz., Pseudomonas fluorescens (Pf1) and Bacillus subtilis (EPCO16) and plant-derived lipoxygenase volatile compound hexanal, were studied in mango fruits against Lasiodiplodia theobromae causing stem-end rot disease. The results showed increased induction of all the defense-related enzymes in mango fruits 3–5 days after dipping treatment with combination of bacterial antagonists and hexanal when compared to untreated control treatment and treatment with fungicide carbendazim in storage condition. The increased activity was observed up to 3 days after treatment and thereafter declined. Further, increased expression of specific isoforms of PO, PPO, SOD and CAT were also observed in the treatment effect of P. fluorescens (0.5%) + hexanal (0.02%) treated fruits against L. theobromae. From the results obtained, it is inferred that due to the enhancement of defense-related enzymes via the phenylpropanoid pathway and due to secretion of secondary metabolites that would play significant role in hindering the pathogen quiescence and further invasion in mango fruits and thereby prevent the fruit rot.

Pectin Enhances Bio-Control Efficacy by Inducing Colonization and Secretion of Secondary Metabolites by Bacillus amyloliquefaciens SQY 162 in the Rhizosphere of Tobacco.

Bacillus amyloliquefaciens is a plant-beneficial Gram-positive bacterium involved in suppressing soil-borne pathogens through the secretion of secondary metabolites and high rhizosphere competence. Biofilm formation is regarded as a prerequisite for high rhizosphere competence. In this work, we show that plant extracts affect the chemotaxis and biofilm formation of B. amyloliquefaciens SQY 162 (SQY 162). All carbohydrates tested induced the chemotaxis and biofilm formation of the SQY 162 strain; however, the bacterial growth rate was not influenced by the addition of carbohydrates. A strong chemotactic response and biofilm formation of SQY 162 were both induced by pectin through stimulation of surfactin synthesis and transcriptional expression of biofilm formation related matrix genes. These results suggested that pectin might serve as an environmental factor in the stimulation of the biofilm formation of SQY 162. Furthermore, in pot experiments the surfactin production and the population of SQY 162 in the rhizosphere significantly increased with the addition of sucrose or pectin, whereas the abundance of the bacterial pathogen Ralstonia decreased. With increased production of secondary metabolites in the rhizosphere of tobacco by SQY 162 and improved colonization density of SQY 162 in the pectin treatment, the disease incidences of bacterial wilt were efficiently suppressed. The present study revealed that certain plant extracts might serve as energy sources or environmental cues for SQY 162 to enhance the population density on tobacco root and bio-control efficacy of tobacco bacterial wilt.

Proteomic insight into the effect of ethanol on citrinin biosynthesis pathway in Monascus purpureus NTU 568

Monascus species produce several potent bioactive metabolites through polyketide secondary metabolic pathways; however, little is known of the regulation of metabolic processes in this organism. Therefore, we investigated the effect of extreme growth conditions on the production of secondary metabolites by Monascus purpureus strain NTU 568 and identified pathways that plausibly regulate the polyketide pathways by using proteomic analysis. Citrinin, a type of antibiotic, is synthesized through the polyketide pathway in M. purpureus NTU 568. We hypothesized that production of citrinin might be inhibited by ethanol. When M. purpureus NTU 568 was cultured in the medium containing 4% ethanol, the secretion of secondary metabolites was inhibited, but the dry cell weight was increased. We also found that branched chain amino acid degradation and the expression level of aldehyde dehydrogenase (ALDH) were downregulated, but proteins related to the heat shock response were induced. Furthermore, polyketide synthesis-related proteins, fatty acid synthase, epoxide hydrolase, and proteins involved in the shikimate secondary metabolic pathway were inhibited by ethanol treatment. These results suggested that reduced production of polyketide metabolites resulted not only from the expression levels of proteins in the polyketide synthesis pathway but also from reduction in the concentration of primary metabolism-generated molecules (e.g., acetyl-CoA, fatty acids) that are used as substrates for polyketide syntheses. This study provides insights into the polyketide secondary metabolism of Monascus as well as into improvement of the production of bioactive secondary metabolites in Monascus species.

Advances in studies on growth metabolism and response mechanisms of medicinal plants under drought stress

Drought stress exerts a considerable effect on growth, physiology and secondary metabolisms of the medicinal plants. It could inhabit the growth of the medicinal plants but promote secretion of secondary metabolites. Other researches indicated that the medicinal plants could depend on the ABA signaling pathway and secreting osmotic substances to resist the drought stress and reduce the damage by it. The article concludes the changes in growth, physiology, secondary metabolisms and response mechanisms of medicinal plants to drought stress that provides a theoretical basis for exploring the relationship between medicinal plants and drought stress.