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23 pages, 2549 KiB

Open AccessArticle

Timing Is Everything: The Metabolic Partitioning of Suberin-Destined Carbon

by Jessica L. Sinka and Mark A. Bernards

Plants 2025, 14(10), 1433; https://doi.org/10.3390/plants14101433 - 10 May 2025

Viewed by 292

Abstract

Suberin is a cell wall-associated biopolymer that possesses both poly(phenolic) and poly(aliphatic) elements assembled into chemically and spatially distinct domains. Domain-specific monomers are formed via a branched pathway between phenolic and aliphatic metabolisms. Previous transcript accumulation data (RNAseq) from early stages of wound-induced [...] Read more.

Suberin is a cell wall-associated biopolymer that possesses both poly(phenolic) and poly(aliphatic) elements assembled into chemically and spatially distinct domains. Domain-specific monomers are formed via a branched pathway between phenolic and aliphatic metabolisms. Previous transcript accumulation data (RNAseq) from early stages of wound-induced suberization revealed highly coordinated, temporal changes in the regulation of these two branches. Notably, phenolic metabolism-associated transcripts accumulated first, indicating a preference toward phenolic production early on post-wounding. To better understand the dynamics of suberin monomer biosynthesis and assembly, we assessed carbon allocation between phenolic and aliphatic metabolisms during wound-induced suberization. To do so, [¹³C₆]-glucose was administered to wound-healing potato tuber discs at different times post-wounding, and patterns of heavy carbon incorporation into (1) primary metabolites and (2) the suberin polymer were assessed. During early stages of wound-healing, carbon from glucose was rapidly incorporated into phenolic-destined metabolites, while at later stages it was shared between phenolic- and aliphatic-destined metabolites. Similarly, the pattern of labelled carbon incorporation into the poly(aliphatic) domain reflected a greater dedication of carbon towards 18:1 w-hydroxy fatty acid and 18:1 dioic acid (the two most abundant aliphatic monomers in potato suberin) later in the wound healing time course. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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14 pages, 1546 KiB

Open AccessArticle

Quillaja lancifolia Immunoadjuvant Saponins Show Toxicity to Herbivores and Pathogenic Fungi

by Anna C. A. Yendo, Luana C. Colling, Hélio N. Matsuura, Lúcia R. B. Vargas, José A. Martinelli, Gabriela Z. Chitolina, Marilene H. Vainstein and Arthur G. Fett-Neto

Plants 2025, 14(8), 1252; https://doi.org/10.3390/plants14081252 - 20 Apr 2025

Viewed by 209

Abstract

Saponins from leaves of Quillaja lancifolia, a native species from southern Brazil, show potent immunoadjuvant activity in experimental vaccine formulations. The accumulation of the immunoadjuvant saponin fraction QB-90 is induced in cultured leaf disks and seedlings by several stresses and stress signaling [...] Read more.

Saponins from leaves of Quillaja lancifolia, a native species from southern Brazil, show potent immunoadjuvant activity in experimental vaccine formulations. The accumulation of the immunoadjuvant saponin fraction QB-90 is induced in cultured leaf disks and seedlings by several stresses and stress signaling molecules, such as osmotic agents, salicylic acid, jasmonic acid, mechanical damage, ultrasound, UV-C radiation, and high light irradiance. These observations suggest a role in plant defense. To further examine this possibility, an investigation of the potential inhibitory role of Q. lancifolia saponins on plant and human pathogenic fungi and two herbivore models was carried out. The screening tests showed that saponin-rich fractions, particularly QB-90, were able to significantly inhibit the growth of Bipolaris micropus, Curvularia inaequalis, Fusarium incarnatum, and Cryptococcus gattii R265. The same metabolites acted as deterrents against the generalist mollusk and insect herbivores Helix aspersa and Spodoptera frugiperda, respectively. Significant reductions in consumption of leaf area and larvae body weight were recorded. Taken together, these data indicate a role for Q. lancifolia saponins in plant defense against diverse herbivores and fungi, having potential as a natural pest control agent and/or as a molecular platform for the development of new environmentally friendly biocide molecules. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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17 pages, 6065 KiB

Open AccessArticle

Functional Analysis of Durum Wheat GASA1 Protein as a Biotechnological Alternative Against Plant Fungal Pathogens and a Positive Regulator of Biotic Stress Defense

by Mohamed Taieb Bouteraa, Walid Ben Romdhane, Alina Wiszniewska, Narjes Baazaoui, Mohammad Y. Alfaifi, Anis Ben Hsouna, Miroslava Kačániová, Stefania Garzoli and Rania Ben Saad

Plants 2025, 14(1), 112; https://doi.org/10.3390/plants14010112 - 2 Jan 2025

Viewed by 1022

Abstract

Plants are frequently challenged by a variety of microorganisms. To protect themselves against harmful invaders, they have evolved highly effective defense mechanisms, including the synthesis of numerous types of antimicrobial peptides (AMPs). Snakins are such compounds, encoded by the GASA (Gibberellic Acid-Stimulated Arabidopsis) [...] Read more.

Plants are frequently challenged by a variety of microorganisms. To protect themselves against harmful invaders, they have evolved highly effective defense mechanisms, including the synthesis of numerous types of antimicrobial peptides (AMPs). Snakins are such compounds, encoded by the GASA (Gibberellic Acid-Stimulated Arabidopsis) gene family, and are involved in the response to biotic and abiotic stress. Here, we examined the function of the newly identified TdGASA1 gene and its encoded protein in Triticum durum subjected to different biotic stress-related simulants, such as mechanical injury, methyl jasmonate (MeJA), indole-3-acetic acid (IAA), salicylic acid (SA), hydrogen peroxide (H₂O₂), as well as infection with pathogenic fungi Fusarium graminearum and Aspergillus niger. We found that in durum wheat, TdGASA1 transcripts were markedly increased in response to these stress simulants. Isolated and purified TdGASA1 protein exhibited significant antifungal activity in the growth inhibition test conducted on eight species of pathogenic fungi on solid and liquid media. Transgenic Arabidopsis lines overexpressing TdGASA1 obtained in this study showed higher tolerance to detrimental effects of H₂O₂, MeJA, and ABA treatment. In addition, these lines exhibited resistance to Fusarium graminearum and Aspergillus niger, which was linked to a marked increase in antioxidant activity in the leaves under stress conditions. This resistance was correlated with the upregulation of pathogenesis-related genes (AtPDF1.2a, AtERF1, AtVSP2, AtMYC2, AtPR1, AtACS6, AtETR1, and AtLOX2) in the transgenic lines. Overall, our results indicate that TdGASA1 gene and its encoded protein respond ubiquitously to a range of biotic stimuli and seem to be crucial for the basal resistance of plants against pathogenic fungi. This gene could therefore be a valuable target for genetic engineering to enhance wheat resistance to biotic stress. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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18 pages, 3743 KiB

Open AccessArticle

The WRKY Family Transcription Factor GmWRKY72 Represses Glyceollin Phytoalexin Biosynthesis in Soybean

by Jie Lin, Ivan Monsalvo, Hyejung Kwon, Sarah Pullano and Nik Kovinich

Plants 2024, 13(21), 3036; https://doi.org/10.3390/plants13213036 - 30 Oct 2024

Cited by 2 | Viewed by 1310

Abstract

Phytoalexins are plant defense metabolites that are biosynthesized transiently in response to pathogens. Despite that their biosynthesis is highly restricted in plant tissues, the transcription factors that negatively regulate phytoalexin biosynthesis remain largely unknown. Glyceollins are isoflavonoid-derived phytoalexins that have critical roles in [...] Read more.

Phytoalexins are plant defense metabolites that are biosynthesized transiently in response to pathogens. Despite that their biosynthesis is highly restricted in plant tissues, the transcription factors that negatively regulate phytoalexin biosynthesis remain largely unknown. Glyceollins are isoflavonoid-derived phytoalexins that have critical roles in protecting soybean crops from the oomycete pathogen Phytophthora sojae. To identify regulators of glyceollin biosynthesis, we used a transcriptomics approach to search for transcription factors that are co-expressed with glyceollin biosynthesis in soybean and stilbene synthase phytoalexin genes in grapevine. We identified and functionally characterized the WRKY family protein GmWRKY72, which is one of four WRKY72-type transcription factors of soybean. Overexpressing and RNA interference silencing of GmWRKY72 in the soybean hairy root system decreased and increased expression of glyceollin biosynthetic genes and metabolites, respectively, in response to wall glucan elicitor from P. sojae. A translational fusion with green fluorescent protein demonstrated that GFP-GmWRKY72 localizes mainly to the nucleus of soybean cells. The GmWRKY72 protein directly interacts with several glyceollin biosynthetic gene promoters and the glyceollin transcription factor proteins GmNAC42-1 and GmMYB29A1 in yeast hybrid systems. The results show that GmWRKY72 is a negative regulator of glyceollin biosynthesis that may repress biosynthetic gene expression by interacting with transcription factor proteins and the DNA of glyceollin biosynthetic genes. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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24 pages, 2598 KiB

Open AccessArticle

Altered Metabolism in Knockdown Lines of Two HXXXD/BAHD Acyltransferases During Wound Healing in Potato Tubers

by Jessica L. Sinka, Indira Queralta-Castillo, Lorena S. Yeung, Isabel Molina, Sangeeta Dhaubhadel and Mark A. Bernards

Plants 2024, 13(21), 2995; https://doi.org/10.3390/plants13212995 - 26 Oct 2024

Viewed by 983

Abstract

Suberin biosynthesis involves the coordinated regulation of both phenolic and aliphatic metabolisms. HXXXD/BAHD acyltransferases occupy a unique place in suberization, as they function to crosslink phenolic and aliphatic monomers during suberin assembly. To date, only one suberin-associated HXXXD/BAHD acyltransferase, StFHT, has been described [...] Read more.

Suberin biosynthesis involves the coordinated regulation of both phenolic and aliphatic metabolisms. HXXXD/BAHD acyltransferases occupy a unique place in suberization, as they function to crosslink phenolic and aliphatic monomers during suberin assembly. To date, only one suberin-associated HXXXD/BAHD acyltransferase, StFHT, has been described in potatoes, whereas, in Arabidopsis, at least two are implicated in suberin biosynthesis. RNAseq data from wound-induced potato tubers undergoing suberization indicate that transcripts for 28 HXXXD/BAHD acyltransferase genes accumulate in response to wounding. In the present study, we generated RNAi knockdown lines for StFHT and another highly wound-induced HXXXD/BAHD acyltransferase, designated StHCT, and characterized their wound-induced suberin phenotype. StFHT-RNAi and StHCT-RNAi knockdown lines share the same aliphatic suberin phenotype of reduced esterified ferulic acid and ferulates, which is similar to the previously described StFHT-RNAi knockdown suberin phenotype. However, the phenolic suberin phenotype differed between the two knockdown genotypes, with StHCT-RNAi knockdown lines having proportionately more p-hydroxyphenyl-derived moieties than either StFHT-RNAi knockdown or empty vector control lines. Analysis of soluble polar metabolites revealed that StHCT catalyzes a step upstream from StFHT. Overall, our data support the involvement of more than one HXXXD/BAHD acyltransferase in potato suberin biosynthesis. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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13 pages, 1230 KiB

Open AccessArticle

Biosynthesis of Piceatannol from Resveratrol in Grapevine Can Be Mediated by Cresolase-Dependent Ortho-Hydroxylation Activity of Polyphenol Oxidase

by Ascensión Martínez-Márquez, Susana Selles-Marchart, Hugo Nájera, Jaime Morante-Carriel, Maria J. Martínez-Esteso and Roque Bru-Martínez

Plants 2024, 13(18), 2602; https://doi.org/10.3390/plants13182602 - 18 Sep 2024

Cited by 2 | Viewed by 1326

Abstract

Piceatannol is a naturally occurring hydroxylated analogue of the stilbene phytoalexin resveratrol that can be found in grape fruit and derived products. Piceatannol has aroused great interest as it has been shown to surpass some human health-beneficial properties of resveratrol including antioxidant activity, [...] Read more.

Piceatannol is a naturally occurring hydroxylated analogue of the stilbene phytoalexin resveratrol that can be found in grape fruit and derived products. Piceatannol has aroused great interest as it has been shown to surpass some human health-beneficial properties of resveratrol including antioxidant activity, several pharmacological activities and also bioavailability. The plant biosynthetic pathway of piceatannol is still poorly understood, which is a bottleneck for the development of both plant defence and bioproduction strategies. Cell cultures of Vitis vinifera cv. Gamay, when elicited with dimethyl-β-cyclodextrin (MBCD) and methyl jasmonate (MeJA), lead to large increases in the accumulation of resveratrol, and after 120 h of elicitation, piceatannol is also detected due to the regiospecific hydroxylation of resveratrol. Therefore, an ortho-hydroxylase must participate in the biosynthesis of piceatannol. Herein, three possible types of resveratrol hydroxylation enzymatic reactions have been tested, specifically, a reaction catalyzed by an NADPH-dependent cytochrome, P450 hydroxylase, a 2-oxoglutarate-dependent dioxygenase and ortho-hydroxylation, similar to polyphenol oxidase (PPO) cresolase activity. Compared with P450 hydoxylase and the dioxygenase activities, PPO displayed the highest specific activity detected either in the crude extract, the particulate or the soluble fraction obtained from cell cultures elicited with MBCD and MeJA for 120 h. The overall yield of PPO activity present in the crude extract (107.42 EU) was distributed mostly in the soluble fraction (66.15 EU) rather than in the particulate fraction (3.71 EU). Thus, partial purification of the soluble fraction by precipitation with ammonium sulphate, dialysis and ion exchange chromatography was carried out. The soluble fraction precipitated with 80% ammonium sulphate and the chromatographic fractions also showed high levels of PPO activity, and the presence of the PPO protein was confirmed by Western blot and LC-MS/MS. In addition, a kinetic characterization of the cresolase activity of partially purified PPO was carried out for the resveratrol substrate, including Vmax and Km parameters. The Km value was 118.35 ± 49.84 µM, and the Vmax value was 2.18 ± 0.46 µmol min⁻¹ mg⁻¹. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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28 pages, 8083 KiB

Open AccessArticle

The Role of Salicylic, Jasmonic Acid and Ethylene in the Development of the Resistance/Susceptibility of Wheat to the SnTox1-Producing Isolate of the Pathogenic Fungus Stagonospora nodorum (Berk.)

by Svetlana Veselova, Tatyana Nuzhnaya and Igor Maksimov

Plants 2024, 13(18), 2546; https://doi.org/10.3390/plants13182546 - 10 Sep 2024

Cited by 3 | Viewed by 1813

Abstract

The SnTox1 effector is a virulence factor of the fungal pathogen Stagonospora nodorum (Berk.), which interacts with the host susceptibility gene Snn1 in a gene-for-gene manner and causes necrosis on the leaves of sensitive wheat genotypes. It is known that salicylic acid [...] Read more.

The SnTox1 effector is a virulence factor of the fungal pathogen Stagonospora nodorum (Berk.), which interacts with the host susceptibility gene Snn1 in a gene-for-gene manner and causes necrosis on the leaves of sensitive wheat genotypes. It is known that salicylic acid (SA), jasmonic acid (JA) and ethylene are the key phytohormones involved in plant immunity. To date, effectors of various pathogens have been discovered that can manipulate plant hormonal pathways and even use hormone crosstalk to promote disease development. However, the role of SnTox1 in manipulating hormonal pathways has not been studied in detail. We studied the redox status and the expression of twelve genes of hormonal pathways and two MAPK genes in six bread wheat cultivars sensitive and insensitive to SnTox1 with or without treatment by SA, JA and ethephon (ethylene-releasing agent) during infection with the SnTox1-producing isolate S. nodorum 1SP. The results showed that SnTox1 controls the antagonism between the SA and JA/ethylene signaling pathways. The SA pathway was involved in the development of susceptibility, and the JA/ethylene pathways were involved in the development of wheat plants resistance to the Sn1SP isolate in the presence of a SnTox1-Snn1 interaction. SnTox1 hijacked the SA pathway to suppress catalase activity, increase hydrogen peroxide content and induce necrosis formation; it simultaneously suppresses the JA and ethylene hormonal pathways by SA. To do this, SnTox1 reprogrammed the expression of the MAPK genes TaMRK3 and TaMRK6 and the TF genes TaWRKY13, TaEIN3 and TaWRKY53b. This study provides new data on the role of SnTox1 in manipulating hormonal pathways and on the role of SA, JA and ethylene in the pathosystem wheat S. nodorum. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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15 pages, 3373 KiB

Open AccessArticle

Application and Evaluation of the Antifungal Activities of Glandular Trichome Secretions from Air/Sun-Cured Tobacco Germplasms against Botrytis cinerea

by Jing Liu, Jiao Wang, Yongmei Du, Ning Yan, Xiao Han, Jianhui Zhang, Yuqing Dou and Yanhua Liu

Plants 2024, 13(14), 1997; https://doi.org/10.3390/plants13141997 - 22 Jul 2024

Cited by 1 | Viewed by 1266

Abstract

The secretions of the glandular trichomes of tobacco leaves and flowers contain abundant secondary metabolites of different compounds, such as cebradanes, labdanes, and saccharide esters. These secondary metabolites have shown interesting biological properties, such as antimicrobial, insecticidal, and antioxidant activity. In this study, [...] Read more.

The secretions of the glandular trichomes of tobacco leaves and flowers contain abundant secondary metabolites of different compounds, such as cebradanes, labdanes, and saccharide esters. These secondary metabolites have shown interesting biological properties, such as antimicrobial, insecticidal, and antioxidant activity. In this study, 81 air/sun-cured tobacco germplasms were used as experimental materials. Quantitative and qualitative analyses of the glandular secretion components were conducted using ultra-performance liquid chromatography–quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF MS) and gas chromatography–mass spectrometry (GC-MS). The ethanol extracts of glandular trichomes from tobacco leaves and flowers were evaluated for antifungal activity against the fungus Botrytis cinerea using the mycelial growth rate method. Orthogonal Partial Least Squares (OPLS) analysis was then performed to determine the relationship between the trichome secretion components and their anti-fungal activity. The results showed significant differences among the antifungal activities of the tested ethanol extracts of tobacco glandular trichomes. The inhibition rates of the upper leaves and flower extracts against B. cinerea were significantly higher than those of the middle and lower leaves, and 59 germplasms (73.75% of the tested resources) showed antifungal rates higher than 50%, with four germplasms achieving a 95% antifungal rate at the same fresh weight concentration (10 mg/mL). The OPLS analysis revealed that the antifungal activity was primarily associated with alpha-cembratriene-diol (α-CBT-diol (Peak7)) and beta-cembratriene-diol (β-CBT-diol (Peak8)), followed by sucrose esters III (SE(III)) and cembratriene-diol oxide. These findings help identify excellent tobacco germplasms for the development and utilization of botanical pesticides against fungi and provide a theoretical reference for the multipurpose utilization of tobacco germplasms. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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17 pages, 2877 KiB

Open AccessArticle

Nitrogen and Silicon Contribute to Wheat Defense’s to Pyrenophora tritici-repentis, but in an Independent Manner

by Andrea Elizabeth Román Ramos, Carlos Eduardo Aucique-Perez, Daniel Debona and Leandro José Dallagnol

Plants 2024, 13(11), 1426; https://doi.org/10.3390/plants13111426 - 21 May 2024

Cited by 2 | Viewed by 1330

Abstract

Nitrogen (N) and silicon (Si) are mineral elements that have shown a reduction in the damage caused by tan spot (Pyrenophora tritici-repentis (Ptr)) in wheat. However, the effects of these elements were studied separately, and the N and Si interaction [...] Read more.

Nitrogen (N) and silicon (Si) are mineral elements that have shown a reduction in the damage caused by tan spot (Pyrenophora tritici-repentis (Ptr)) in wheat. However, the effects of these elements were studied separately, and the N and Si interaction effect on wheat resistance to tan spot remains elusive. Histocytological and biochemical defense responses against Ptr in wheat leaves treated with Si (+Si) at low (LN) and high N (HN) inputs were investigated. Soil amendment with Si reduced the tan spot severity in 18% due to the increase in the leaf Si concentration (around 30%), but it was affected by the N level used. The superoxide dismutase (SOD) activity was higher in +Si plants and inoculated with Ptr, leading to early and higher H₂O₂ and callose accumulation in wheat leaf. Interestedly, phenylalanine ammonia-lyase (PAL) activity was induced by the Si supplying, being negatively affected by the HN rate. Meanwhile, catalase (CAT), and peroxidase (POX) activities showed differential response patterns according to the Si and N rates used. Tan spot severity was reduced by both elements, but their interaction does not evidence synergic effects in this disease’s control. Wheat plants from −Si and HN and +Si and LN treatments recorded lower tan spot severity. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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21 pages, 3073 KiB

Open AccessArticle

Aphid Resistance Segregates Independently of Cardenolide and Glucosinolate Content in an Erysimum cheiranthoides (Wormseed Wallflower) F2 Population

by Mahdieh Mirzaei, Gordon C. Younkin, Adrian F. Powell, Martin L. Alani, Susan R. Strickler and Georg Jander

Plants 2024, 13(4), 466; https://doi.org/10.3390/plants13040466 - 6 Feb 2024

Cited by 1 | Viewed by 1502

Abstract

Plants in the genus Erysimum produce both glucosinolates and cardenolides as a defense mechanism against herbivory. Two natural isolates of Erysimum cheiranthoides (wormseed wallflower) differed in their glucosinolate content, cardenolide content, and their resistance to Myzus persicae (green peach aphid), a broad generalist [...] Read more.

Plants in the genus Erysimum produce both glucosinolates and cardenolides as a defense mechanism against herbivory. Two natural isolates of Erysimum cheiranthoides (wormseed wallflower) differed in their glucosinolate content, cardenolide content, and their resistance to Myzus persicae (green peach aphid), a broad generalist herbivore. Both classes of defensive metabolites were produced constitutively and were not further induced by aphid feeding. To investigate the relative importance of glucosinolates and cardenolides in E. cheiranthoides defense, we generated an improved genome assembly, genetic map, and segregating F2 population. The genotypic and phenotypic analysis of the F2 plants identified quantitative trait loci, which affected glucosinolates and cardenolides, but not the aphid resistance. The abundance of most glucosinolates and cardenolides was positively correlated in the F2 population, indicating that similar processes regulate their biosynthesis and accumulation. Aphid reproduction was positively correlated with glucosinolate content. Although the overall cardenolide content had little effect on aphid growth and survival, there was a negative correlation between aphid reproduction and helveticoside abundance. However, this variation in defensive metabolites could not explain the differences in aphid growth on the two parental lines, suggesting that processes other than the abundance of glucosinolates and cardenolides have a predominant effect on aphid resistance in E. cheiranthoides. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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13 pages, 1893 KiB

Open AccessArticle

Nematocidal Potential of Phenolic Acids: A Phytochemical Seed-Coating Approach to Soybean Cyst Nematode Management

by Ping Yates, Juddy Janiol, Changbao Li and Bao-Hua Song

Plants 2024, 13(2), 319; https://doi.org/10.3390/plants13020319 - 21 Jan 2024

Cited by 6 | Viewed by 2137

Abstract

Soybeans, one of the most valuable crops worldwide, are annually decimated by the soybean cyst nematode (SCN), Heterodera glycines, resulting in massive losses in soybean yields and economic revenue. Conventional agricultural pesticides are generally effective in the short term; however, they pose [...] Read more.

Soybeans, one of the most valuable crops worldwide, are annually decimated by the soybean cyst nematode (SCN), Heterodera glycines, resulting in massive losses in soybean yields and economic revenue. Conventional agricultural pesticides are generally effective in the short term; however, they pose growing threats to human and environmental health; therefore, alternative SCN management strategies are urgently needed. Preliminary findings show that phenolic acids are significantly induced during SCN infection and exhibit effective nematocidal activities in vitro. However, it is unclear whether these effects occur in planta or elicit any negative effects on plant growth traits. Here, we employed a phytochemical-based seed coating application on soybean seeds using phenolic acid derivatives (4HBD; 2,3DHBA) at variable concentrations and examined SCN inhibition against two SCN types. Moreover, we also examined plant growth traits under non-infected or SCN infected conditions. Notably, 2,3DHBA significantly inhibited SCN abundance in Race 2-infected plants with increasingly higher chemical doses. Interestingly, neither compound negatively affected soybean growth traits in control or SCN-infected plants. Our findings suggest that a phytochemical-based approach could offer an effective, more environmentally friendly solution to facilitate current SCN management strategies and fast-track the development of biopesticides to sustainably manage devastating pests such as SCN. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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Review

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14 pages, 1144 KiB

Open AccessReview

Silicon-Mediated Interactions Between Plant Antagonists

by Marie-Emma Denarié, Uffe N. Nielsen, Susan E. Hartley and Scott N. Johnson

Plants 2025, 14(8), 1204; https://doi.org/10.3390/plants14081204 - 14 Apr 2025

Viewed by 539

Abstract

The prolonged arms race between plants and their antagonists has resulted in the evolution of multiple plant defence mechanisms to combat attacks by pests and pathogens. Silicon (Si) accumulation occurs mainly in grasses and provides a physical barrier against antagonists. Biochemical pathways may [...] Read more.

The prolonged arms race between plants and their antagonists has resulted in the evolution of multiple plant defence mechanisms to combat attacks by pests and pathogens. Silicon (Si) accumulation occurs mainly in grasses and provides a physical barrier against antagonists. Biochemical pathways may also be involved in Si-mediated plant resistance, although the precise mode of action in this case is less clear. Most studies have focussed on Si-based effects against single attackers. In this review, we consider how Si-based plant resistance operates when simultaneously and/or sequentially attacked by insect herbivores, fungal phytopathogens, and plant parasitic nematodes and how the plant hormones jasmonic acid (JA) and salicylic acid (SA) are involved. Si defence may mediate both intra- and interspecific competition and facilitation. Si has been found to impact plant-mediated interactions between insect herbivores within the same feeding guild and across different feeding guilds, with varying patterns of JA and SA. These results suggest that hormonal crosstalk may play a role in the Si-mediated effects, although this finding varied between studies. While some reports support the notion that JA is linked to Si responses, others indicate that Si supplementation reduces JA production. In terms of phytopathogens, SA has not been found to be involved in Si-mediated defences. Improving our understanding of Si-mediated plant defence could be beneficial for sustainable agriculture under future climates. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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55 pages, 1250 KiB

Open AccessReview

Plant Signaling Hormones and Transcription Factors: Key Regulators of Plant Responses to Growth, Development, and Stress

by Ayomi S. Thilakarathne, Fei Liu and Zhongwei Zou

Plants 2025, 14(7), 1070; https://doi.org/10.3390/plants14071070 - 31 Mar 2025

Viewed by 1169

Abstract

Plants constantly encounter a wide range of biotic and abiotic stresses that adversely affect their growth, development, and productivity. Phytohormones such as abscisic acid, jasmonic acid, salicylic acid, and ethylene serve as crucial regulators, integrating internal and external signals to mediate stress responses [...] Read more.

Plants constantly encounter a wide range of biotic and abiotic stresses that adversely affect their growth, development, and productivity. Phytohormones such as abscisic acid, jasmonic acid, salicylic acid, and ethylene serve as crucial regulators, integrating internal and external signals to mediate stress responses while also coordinating key developmental processes, including seed germination, root and shoot growth, flowering, and senescence. Transcription factors (TFs) such as WRKY, NAC, MYB, and AP2/ERF play complementary roles by orchestrating complex transcriptional reprogramming, modulating stress-responsive genes, and facilitating physiological adaptations. Recent advances have deepened our understanding of hormonal networks and transcription factor families, revealing their intricate crosstalk in shaping plant resilience and development. Additionally, the synthesis, transport, and signaling of these molecules, along with their interactions with stress-responsive pathways, have emerged as critical areas of study. The integration of cutting-edge biotechnological tools, such as CRISPR-mediated gene editing and omics approaches, provides new opportunities to fine-tune these regulatory networks for enhanced crop resilience. By leveraging insights into transcriptional regulation and hormone signaling, these advancements provide a foundation for developing stress-tolerant, high-yielding crop varieties tailored to the challenges of climate change. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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31 pages, 1685 KiB

Open AccessReview

Biochemical Defence of Plants against Parasitic Nematodes

by Birhanu Kahsay Meresa, Jasper Matthys and Tina Kyndt

Plants 2024, 13(19), 2813; https://doi.org/10.3390/plants13192813 - 8 Oct 2024

Cited by 2 | Viewed by 2524

Abstract

Plant parasitic nematodes (PPNs), such as Meloidogyne spp., Heterodera spp. and Pratylenchus spp., are obligate parasites on a wide range of crops, causing significant agricultural production losses worldwide. These PPNs mainly feed on and within roots, impairing both the below-ground and the above-ground [...] Read more.

Plant parasitic nematodes (PPNs), such as Meloidogyne spp., Heterodera spp. and Pratylenchus spp., are obligate parasites on a wide range of crops, causing significant agricultural production losses worldwide. These PPNs mainly feed on and within roots, impairing both the below-ground and the above-ground parts, resulting in reduced plant performance. Plants have developed a multi-component defence mechanism against diverse pathogens, including PPNs. Several natural molecules, ranging from cell wall components to secondary metabolites, have been found to protect plants from PPN attack by conferring nematode-specific resistance. Recent advances in omics analytical tools have encouraged researchers to shed light on nematode detection and the biochemical defence mechanisms of plants during nematode infection. Here, we discuss the recent progress on revealing the nematode-associated molecular patterns (NAMPs) and their receptors in plants. The biochemical defence responses of plants, comprising cell wall reinforcement; reactive oxygen species burst; receptor-like cytoplasmic kinases; mitogen-activated protein kinases; antioxidant activities; phytohormone biosynthesis and signalling; transcription factor activation; and the production of anti-PPN phytochemicals are also described. Finally, we also examine the role of epigenetics in regulating the transcriptional response to nematode attack. Understanding the plant defence mechanism against PPN attack is of paramount importance in developing new, effective and sustainable control strategies. Full article

(This article belongs to the Special Issue Biochemical Defenses of Plants)

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