Lignification is a typical symptom of chilling injury (CI) in loquat fruit under chilling stress. This study investigated the impact of hydrogen sulfide (H2S) on endogenous H2S, shikimate, ...phenylpropanoid, and cell wall metabolisms of loquat fruit during refrigeration. The findings suggested that H2S treatment hindered the rise in the CI index and firmness while delaying the reduction in extractable juice, soluble sugar, and titratable acid content of loquat fruit. Besides, H2S treatment promoted the endogenous H2S content, which was correlated with the increase in activities of related H2S synthase enzymes. Furthermore, H2S suppressed enzymes involved in shikimate and phenylpropanoid metabolisms, thereby decreasing phenylalanine and lignin accumulation. Simultaneously, H2S treatment retarded the increases in insoluble pectin, hemicellulose, and cellulose by orchestrating cell wall-modifying enzymes. This work indicates that H2S treatment may alleviate chilling-induced lignification by inhibiting lignin accumulation and enhancing the depolymerization and solubilization of cell wall polysaccharides.
•H2S treatment alleviated the chilling-induced lignification in loquat fruit during cold storage.•H2S treatment promoted endogenous H2S accumulation in loquat fruit.•H2S treatment regulated the shikimate and phenylpropanoid metabolisms to reduce lignin accumulation.•H2S treatment regulated abnormal cell wall metabolism by modulating the degradation of cell wall polysaccharides.
ABSTRACT This communication turn on the use of Solanun gilo (Solanaceae) for lignification test on the nutritional point of view. This plant was chosen due its fast growth, high calcium mobility and ...low lignin content (15,51%). The experiment was carried out using calcium sulfate (CaSO4) and calcium chloride (CaCl2) for weekly and biweekly application. The treated plants with CaSO4/CaCl2 (biweekly application) showed 4% of additional lignin content. High syringyl unit concentration was also verified at Guaiacyl: Syringyl ratio (G: S) of 0.8:1 and 1.2:1, for weekly and biweekly application, respectively. The estimation of the lignin content and its composition were performed by Klason and infrared spectroscopy methods.
Tsai Tai is one of the most important vegetables in the world. However, harvested Tsai Tai is prone to leaf yellowing and stem lignification, leading to apparent deterioration in quality and a ...decrease in value during storage. This study examines the effects of ethylene treatment on lignification in harvested Tsai Tai during storage. It was found that treatment with a low concentration (0.2 mM) of ethylene significantly promotes lignin accumulation in both the stems and leaves of harvested Tsai Tai, without affecting leaf yellowing. Ethylene exposure increased lignin levels, enhanced peroxidase (POD) activity, and stimulated hydrogen peroxide (H2O2) production. In contrast, treatments with 1-methylcyclopropene (1-MCP) and silver nitrate (AgNO3) inhibited lignin accumulation, reduced POD activity, and decreased H2O2 levels in harvested Tsai Tai during storage. Transcriptome profiling analysis of stems treated with a low concentration of ethylene and 1-MCP revealed that numerous genes were impacted by ethylene and 1-MCP during the storage of harvested Tsai Tai. Moreover, two POD genes (POD67 and POD71) were identified as key contributors to lignin biosynthesis and are regulated by transcription factors such as basic helix-loop-helix (bHLH), basic leucine zipper 1 (bZIP1), and bZIP2. The genes and transcription factors identified provide valuable targets for future breeding strategies aiming to control lignin biosynthesis. This could facilitate the development of new varieties with improved storage characteristics, particularly those associated with lignin content and quality. This research paves the way for advancing Tsai Tai breeding efforts and enhancing postharvest storage traits.
•Ethylene can trigger lignification of Tsai Tai without affecting leaf yellowing.•Ethylene signal transduction plays a key role in the lignification of Tsai Tai.•Ethylene and 1-MCP treatments altered the expression of lignin synthesis genes in Tsai Tai.•RNA-Seq revealed two POD genes as key lignin biosynthesis gene in Tsai Tai.•Three transcription factors were identified as the regulators of two key POD genes.
Plant secondary cell-wall (SCW) deposition and lignification are affected by both seasonal factors and abiotic stress, and these responses may involve the hormone abscisic acid (ABA). However, the ...mechanisms involved are not clear. Here we show that mutations that limit ABA synthesis or signaling reduce the extent of SCW thickness and lignification in
through the core ABA-signaling pathway involving SnRK2 kinases. SnRK2.2. 3 and 6 physically interact with the SCW regulator NAC SECONDARY WALL THICKENING PROMOTING FACTOR 1 (NST1), a NAC family transcription factor that orchestrates the transcriptional activation of a suite of downstream SCW biosynthesis genes, some of which are involved in the biosynthesis of cellulose and lignin. This interaction leads to phosphorylation of NST1 at Ser316, a residue that is highly conserved among NST1 proteins from dicots, but not monocots, and is required for transcriptional activation of downstream SCW-related gene promoters. Loss of function of NST1 in the
mutant background results in lack of SCWs in the interfascicular fiber region of the stem, and the Ser316Ala mutant of NST1 fails to complement this phenotype and ABA-induced lignin pathway gene expression. The discovery of NST1 as a key substrate for phosphorylation by SnRK2 suggests that the ABA-mediated core-signaling cascade provided land plants with a hormone-modulated, competitive desiccation-tolerance strategy allowing them to differentiate water-conducting and supporting tissues built of cells with thicker cell walls.
Summary
Verticillium dahliae is a phytopathogenic fungal pathogen that causes vascular wilt diseases responsible for considerable decreases in cotton yields. The lignification of cell wall ...appositions is a conserved basal defence mechanism in the plant innate immune response. However, the function of laccase in defence‐induced lignification has not been described. Screening of an SSH library of a resistant cotton cultivar, Jimian20, inoculated with V. dahliae revealed a laccase gene that was strongly induced by the pathogen. This gene was phylogenetically related to AtLAC15 and contained domains conserved by laccases; therefore, we named it GhLAC15. Quantitative reverse transcription‐polymerase chain reaction indicated that GhLAC15 maintained higher expression levels in tolerant than in susceptible cultivars. Overexpression of GhLAC15 enhanced cell wall lignification, resulting in increased total lignin, G monolignol and G/S ratio, which significantly improved the Verticillium wilt resistance of transgenic Arabidopsis. In addition, the levels of arabinose and xylose were higher in transgenic plants than in wild‐type plants, which resulted in transgenic Arabidopsis plants being less easily hydrolysed. Furthermore, suppression of the transcriptional level of GhLAC15 resulted in an increase in susceptibility in cotton. The content of monolignol and the G/S ratio were lower in silenced cotton plants, which led to resistant cotton cv. Jimian20 becoming susceptible. These results demonstrate that GhLAC15 enhances Verticillium wilt resistance via an increase in defence‐induced lignification and arabinose and xylose accumulation in the cell wall of Gossypium hirsutum. This study broadens our knowledge of defence‐induced lignification and cell wall modifications as defence mechanisms against V. dahliae.
Nowadays, nanoparticles are extensively being utilized in medicine, industry, and agriculture thus distributed into the environment. Hence, it is essential to examine exactly the impact of these ...materials on a variety of organisms, including various species of plants. Therefore, in the current study, we compared the effects of sodium silicate and nano silicon (SiNP) (both at two concentrations of 5 and 10 mM) separately on lignification of the xylem cell wall, antioxidant enzyme activities, ultrastructure of leaf and root cells, expression of silicon transporter (Lsi1) and phenylalanine ammonia lyase (PAL), and also evaluated the protein content and chemical content of oat plants (Avena sativa L.) cultured hydroponically. The results indicated that SiNPs didn't have a toxic effect on the oat plants, and in many cases they enhanced plant growth. The effect of SiNPs on the chemical content of the treated plants was almost identical with silicate. The silicon transporter (Lsi1) gene was expressed in plants exposed to SiNPs, however, at lower levels (∼37% in roots) than those exposed to silicate treatments. The SiNPs increased PAL expression and lignification in leaves and roots, however, at lower levels those of silicate (˃50% in fourth leaves of 10 mM concentration). They were aggregated in the roots (268–366 nm) and deposited in nano size on the cell walls of leaves. In general, their effects in the plants were identical to silicate but differed in intensity.
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•The silicon nanoparticles (SiNPs) were not toxic but also leaded to better growth in oat plants.•The SiNPs were taken up both silicon transporter (Lsil) and apoplastic pathway.•The deposition of SiNPs in nano size in leaves may be a risk for other organisms.•The SiNPs were aggregated in roots and deposited in nano size on cell walls of leaves.
Summary
Plants have developed tissue‐specific defense strategies in response to various herbivores with different feeding habits. Although defense responses to leaf‐chewing insects have been well ...studied, little is known about stem‐specific responses, particularly in the pith, to stem‐boring herbivores.
To understand the stem‐specific defense, we first conducted a comparative transcriptomic analysis of the wild tobacco Nicotiana attenuata before and after attack by the leaf‐chewing herbivore Manduca sexta and the stem borer Trichobaris mucorea. When the stem‐boring herbivore attacked, lignin‐associated genes were upregulated specifically in the inner parenchymal cells of the stem, the pith; lignin also accumulated highly in the attacked pith. Silencing the lignin biosynthetic gene cinnamyl alcohol dehydrogenase enhanced the performance of the stem‐boring herbivore but had no effect on the growth of the leaf‐chewing herbivore.
Two‐dimensional nuclear magnetic resonance results revealed that lignified pith contains feruloyltyramine as an unusual lignin component in the cell wall, as a response against stem‐boring herbivore attack. Pith‐specific lignification induced by the stem‐boring herbivore was modulated by both jasmonate and ethylene signaling.
These results suggest that lignin provides a stem‐specific inducible barrier, protecting plants against stem‐boring insects.
Two novel MYB transcription factors are involved in lignin biosynthesis and flesh lignification in loquat fruit, which are manipulated by temperature condition and treatments.
Background and aims Root-knot nematodes (RKN; Meloidogyne spp.) are among the highly prevalent and significantly detrimental pathogens that cause severe economic and yield losses in crops. Currently, ...control of RKN primarily relies on the application of chemical nematicides but it has environmental and public health concerns, which open new doors for alternative methods in the form of biological control. Methods In this study, we investigated the nematicidal and attractive activities of an endophytic strain WF01 against Meloidogyne incognita in concentration-dependent experiments. The active nematicidal metabolite was extracted in the WF01 crude extract through the Sephadex column, and its structure was identified by nuclear magnetic resonance and mass spectrometry data. Results The strain WF01 was identified as Aspergillus tubingensis based on morphological and molecular characteristic s . The nematicidal and attractive metabolite of A. tubingensis WF01 was identified as oxalic acid (OA), which showed solid nematicidal activity against M. incognita , having LC 50 of 27.48 μg ml –1 . The Nsy-1 of AWC and Odr-7 of AWA were the primary neuron genes for Caenorhabditis elegans to detect OA. Under greenhouse, WF01 broth and 200 μg ml –1 OA could effectively suppress the disease caused by M. incognita on tomatoes respectively with control efficiency (CE) of 62.5% and 70.83%, and promote plant growth. In the field, WF01-WP and 8% OA-WP formulations showed moderate CEs of 51.25%–61.47% against RKN in tomato and tobacco. The combined application of WF01 and OA resulted in excellent CEs of 66.83% and 69.34% toward RKN in tomato and tobacco, respectively. Furthermore, the application of WF01 broth or OA significantly suppressed the infection of J2s in tomatoes by upregulating the expression levels of the genes ( PAL , C4H , HCT , and F5H ) related to lignin synthesis, and strengthened root lignification. Conclusion Altogether, our results demonstrated that A. tubingensis WF01 exhibited multiple weapons to control RKN mediated by producing OA to lure and kill RKN in a concentration-dependent manner and strengthen root lignification. This fungus could serve as an environmental bio-nematicide for managing the diseases caused by RKN.
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•611 metabolites were detected in chestnuts at different calcification degrees.•55 key metabolites were highly correlated with chestnut calcification.•A potential metabolic network ...related to chestnut calcification was established.•The damage of cell membrane was tightly connected with calcification.•The degradation and hardening of cell wall were highly related to calcification.
Chestnut calcification is a quality deterioration due to fast water loss, which has been of deep concern for chestnut quality control because its mechanism is unclear. In order to find out the different key metabolites and metabolic pathways related to the occurrence of chestnut calcification, in this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) based widely targeted metabolomics analysis was performed on chestnuts that were stored at 50%–55% (low relative humidity, LRH) at 25 °C and 85%–90% (high relative humidity, HRH) at 25 °C. A total of 611 metabolites were detected, and 55 differentially accumulated metabolites were identified as key metabolites involved in chestnut calcification process. The decrease in some monosaccharides accompanied with the increase in some unsaturated fatty acids indicated the degradation of chestnut cell wall and cell membrane during calcification process. As a stress response, amino acid metabolism related to membrane stability was significantly activated. In addition, the enhancement of phenylpropanoid biosynthesis pathway and flavonoid biosynthesis pathway characterized by the accumulation of lignin precursors and antioxidants suggested that lignification process was triggered in calcified chestnut. Therefore, the degradation and hardening of the cell wall and membrane damage were proposed to be associated with the calcification occurrence of chestnut. The metabolic profile of chestnut characterized in this study provided new insights into chestnut calcification process and laid a foundation for further chestnut quality control.
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