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Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pea, Pisum sativum L. (2n = 14), is the third most important legume crop worldwide after common bean and chickpea. Pea production is severely affected by rust caused by Uromyces viciae-fabae. Lignification is one of the most important mechanisms playing a very significant role in plant disease resistance. In the present study, a total of 115 pea entries of the Australian germplasm together with four standard controls were observed for the presence of total lignin content (72 h) and its accumulation in relation to the different components of resistance. Out of all the test entries, one resistant entry 'EC865975' showed the maximum increase in total lignin content even more than the resistant check. It also exhibited a low AUDPC (the Area under the Disease Progress Curve) value of 292 and showed formation of smaller pustules measuring 0.7 mm in size with reduction in their number. Further, it was found that the total lignin content was highly negatively correlated (r = -0.796) with AUDPC. The higher accumulation of lignin content was found in resistant test entries over susceptible ones. The principal component analysis of the different parameters revealed that the total lignin content and AUDPC were only the parameters mostly contributing to the total phenotypic variation to the extent of 81.92% as they exhibited their Eigenvalue > 1. Further, the regression analysis considering the total lignin content as the independent variable and AUDPC, size and number of pustules, 100 seed weight and seed area as predictor variables revealed that the total lignin content caused 75.2% alteration in other predictor variables. Hence, the present study confirmed that the lignification can be used as a key biochemical parameter for screening of resistant sources from the various pea germplasms. [ABSTRACT FROM AUTHOR]

SUMMARY Lignification of the cell wall in pear (Pyrus) fruit results in the formation of stone cells, which affects the texture and quality of the fruit. However, it is still unclear that how different transcription factors (TFs) work together to coordinate the synthesis and deposition of lignin. Here, we examined the transcriptome of pear varieties with different stone cell contents and found a key TF (PbAGL7) that can promote the increase of stone cell contents and secondary cell wall thicknesses. In addition, PbAGL7 can facilitate the expression level of lignin biosynthesis‐related genes and accelerate the lignin biosynthesis in pear fruit and Arabidopsis. However, PbAGL7 did not directly bind to the promoters of PbC3H1 and PbHCT17 which are crucial genes involved in lignin biosynthesis. On the other hand, yeast two‐hybrid (Y2H) library showed that PbNAC47 and PbMYB73 interacted with PbAGL7 in the nucleus. PbNAC47 and PbMYB73 also increased the stone cell and lignin contents, and upregulated the expressions of PbC3H1 and PbHCT17 by binding to the SNBE and AC elements, respectively. Moreover, PbNAC47 also interacted with PbMYB73 to form PbAGL7–PbNAC47–PbMYB73 complex. This complex significantly activated the expression levels of PbC3H1 and PbHCT17 and promoted lignin biosynthesis to form stone cells in pear fruit. Overall, our study provides new insights into the molecular mechanism of TFs that coordinately regulate the stone cell formation in pear fruit and extend our knowledge to understand cell wall lignification in plants. [ABSTRACT FROM AUTHOR]

Lignin is a crucial component of plant cell walls, supporting plant growth by providing mechanical strength, aiding water transport, and enhancing resistance to pathogens. Despite extensive research on lignin biosynthesis as a renewable resource, understanding the transport and deposition of its monomers remains challenging. In this study, a novel precursor monomer was designed, SALK (alkyne-tagged sinapyl alcohol surrogate), for tracking and localizing lignin in flax cells, aiming to explore the in vivo lignification process. First, the dehydrogenation polymer (DHP) of SALK was synthesized and its biocompatibility was successfully verified. After click chemistry to label fluorescent dyes, incorporation of novel lignin monomers during the polymerization process was detected and imaged successfully. The results indicated that the chemical reporter could provide detailed localization information during polymerization. It was found that lignification in the bast fiber (R) cells and fiber tracheid (FT) cells of flax was different. FT cells closer to the pith showed higher maturity and lower lignification degree. While R cells, regardless of their proximity to the pith, show a relatively consistent lignification trend. At the single-cell level, lignin deposition initiates at cell corners and the middle lamella, followed by secondary cell wall, with the highest lignin content in the secondary wall of mature cells. The results of this work reveal the potential of chemical reporters in providing detailed insights into the in vivo lignification process, advancing the technology for studying the formation and function of plant cell walls. [ABSTRACT FROM AUTHOR]

Summary: Cold plasma (CP) is a promising technology for fresh‐cut fruits and vegetables. In this study, the effects of CP on postharvest senescence, especially from the perspective of oxidative response of fresh‐cut bamboo shoots were examined, including the colour, firmness, lignin content, reactive oxygen species (ROS) accumulation and antioxidant enzymatic activities. CP treatments delayed the browning of bamboo shoots indicating by the increase of L* and b* values and decrease of a* value. The browning inhibition coincided with the reduction of PPO activities up to 62% by CP at 20 kV. Cellulose and lignin accumulated during storage. CP at 30 kV accelerated lignification, whereas CP at 10 and 20 kV inhibited the increase. These results were also reflected by PAL, CAD and POD activities that were enhanced by CP at 30 kV and inhibited by CP at 10 and 20 kV. The content of O2− and H2O2 was significantly increased at the first 3 days and decreased afterwards, with a similar trend of antioxidant enzymes SOD and CAT. As smaller increases in H2O2 and O2− production in CP treated samples than in control were probably attributed to elevated CP‐induced SOD activity. In addition, there was a delay effect observed in the internal parts of bamboo shoots compared with the surface (<5 mm thick). CP extended the shelf‐life of bamboo shoots by triggering the antioxidant defence. CP at 20 kV exhibited the best preservative effect on fresh‐cut bamboo shoots. [ABSTRACT FROM AUTHOR]

Between 2023 and 2024, a type of green alga was observed for the first time settling on Oil-tea Camellia leaves and branches in the eastern Oil-tea Camellia planting area of Hainan Island, forming a layer of gray-green moss with a rough surface that seriously interfered with the leaves' normal photosynthesis. To further research the issue, this study used the plant photosynthesis measurement system and the paraffin sectioning technique to compare and analyze the changes in photosynthetic characteristics and anatomical structure of healthy and green algal-covered Oil-tea Camellia leaves. At the same time, the algal strain was effectively separated and purified using the plate delineation method, and its species classification was determined by combining morphological observation and molecular identification based on SSU-ITS sequences. The results of the study demonstrated that the coating of green alga facilitated the lignification of the leaf's epidermal cell walls. After being covered by the green alga, the intercellular CO2 concentration (Ci) increased significantly by 21.5%, while the net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) all significantly decreased by 72.8%, 30.4%, and 24.9%, respectively. More specifically, the green alga that covers the leaves of Oil-tea Camellia was identified as Desmodesmus armatus of Chlorophyta. Notably, the green alga had a long growth cycle, did not undergo a decline phase within one month, had an optimal growth pH of 11.0, and could flourish in excessively alkaline conditions. In conclusion, this study not only reported for the first time the phenomena of D. armatus infesting Oil-tea Camellia leave, but also showed its unique physiological and ecological properties, providing a foundation for future research on relevant prevention and control approaches. [ABSTRACT FROM AUTHOR]

Postharvest ethylene accumulation and lignification are significant issues affecting the storage quality of fresh faba beans, resulting in rapid quality decline. However, there is still a lack of effective preservation methods to preserve the quality of faba beans during storage. This study aimed to investigate the regulation of lignification in faba beans during storage using a high-efficiency ethylene remover (HEER), examining physiological responses, key enzyme activities, and transcriptomic changes. Results showed that the HEER treatment inhibited the lignification, reducing it by 45% and lowering the respiratory rate of fresh pods by 32.8% during storage. Additionally, the HEER treatment suppressed respiration rates and the activities of lignin synthesis-related enzymes, including phenylalanine ammonia-lyase (from 353.73 to 246.60 U/g), cinnamic acid-4-hydroxylase (from 635.86 to 125.00 U/g), 4-coumarate: coenzyme A ligase (from 1008.57 to 516.52 U/g), and cinnamyl-alcohol dehydrogenase (from 129.42 to 37.12 U/g), thus slowing lignin accumulation. During storage, the hardness of fresh faba bean increased by 9.79% from the initial period, being 1.44 times higher than that of HEER. On days 8 and 16 of storage, the respiratory rate of the treated beans decreased by 24.38% and 4.12%, respectively. Physiological and enzyme activity analyses indicated that HEER treatment-induced increase in hardness was associated with the phenylpropanoid metabolic pathway. Moreover, the HEER significantly down-regulated the expression of several key genes, namely FaPAL, FaC4H, and FaCAD. This study helps to deepen the understanding of the inhibition of lignification by HEER and provide new insights for the development of preservation technology of faba bean. [ABSTRACT FROM AUTHOR]

The bHLH transcription factors are important plant regulators against abiotic stress and involved in plant growth and development. In this study, SlALC, a gene coding for a prototypical DNA-binding protein in the bHLH family, was isolated, and SlALC-overexpression tomato (SlALC-OE) plants were generated by Agrobacterium-mediated genetic transformation. SlALC transgenic lines manifested higher osmotic stress tolerance than the wild-type plants, estimated by higher relative water content and lower water loss rate, higher chlorophyll, reducing sugar, starch, proline, soluble protein contents, antioxidant enzyme activities, and lower MDA and reactive oxygen species contents in the leaves. In SlALC-OE lines, there were more significant alterations in the expression of genes associated with stress. Furthermore, SlALC-OE fruits were more vulnerable to dehiscence, with higher water content, reduced lignin content, SOD/POD/PAL enzyme activity, and lower phenolic compound concentrations, all of which corresponded to decreased expression of lignin biosynthetic genes. Moreover, the dual luciferase reporter test revealed that SlTAGL1 inhibits SlALC expression. This study revealed that SlALC may play a role in controlling plant tolerance to drought and salt stress, as well as fruit lignification, which influences fruit dehiscence. The findings of this study have established a foundation for tomato tolerance breeding and fruit quality improvement. [ABSTRACT FROM AUTHOR]

Plant cells withstand mechanical stress originating from turgor pressure by robustly maintaining the mechanical properties of the cell wall. This applies at the organ scale as well; many plant stems act as pressurized cylinders, where the epidermis is under tension and inner tissues are under compression. The clavata3 de-etiolated3 (clv3-8 det3-1) double mutant of Arabidopsis thaliana displays cracks in its stems because of a conflict between the mechanical properties of the weak epidermis and over-proliferation of inner stem tissues. In this work, we conducted three-point bending tests on various Arabidopsis thaliana mutants, including those displaying the stem cracking phenotype, to examine the differences in their mechanical properties. The clv3-8 det3-1 double mutant exhibited reduced stem stiffness, consistent with reduced differentiation due to the clv3-8 mutation. Yet, in clv3-8, stem cross-sectional area was increased associating with the increase in vascular bundle number, and stem cross-sections displayed various shapes. To uncouple the contribution of geometry and cell-wall differentiation to the mechanical properties of the whole stems, we tested the contribution of lignified fibers to stem stiffness. In order to suppress lignin deposition in stems genetically, we generated multiple higher-order mutants by crossing clv3-8 and/or det3-1 with nst1-1 nst3-1, in which lignin deposition is suppressed. Stem stiffness was reduced markedly in all nst1-1 nst3-1 mutant backgrounds. Overall, our results suggest that stem stiffness relies on the presence of differentiated, lignified, fiber tissue as well as on the alignment or spatial distribution of vascular bundles within the stem organ. [ABSTRACT FROM AUTHOR]

Mangroves have unique adaptations that help them survive in highly saline and hypoxic environments. The present study examines how two mangrove species, namely Kandelia candel (L.) Druce and Rhizophora mucronata Lam., well known for their ultrafiltration capability, responded to different salinity levels. We have conducted histochemical, biochemical and gene expression analyses of lignin and cell wall components from the two non-salt-secreting mangrove species treated with different salinity gradients. Root length decreased at higher salinity treatments for K. candel (11.7–13.8 cm in freshwater; 5.7–6.7 cm at 20 ppt), while R. mucronata (4.9–6.4 cm in freshwater; 5.5–9.4 cm at 35 ppt) showed no significant change. The rate of lignin deposition near the vascular bundles varied from freshwater to salt treatments and between the species. Overall lignin content in the K. candel roots increased at higher salinity (40.6–70.6 µg/mg at freshwater to 53.9–145.1 µg/mg at 20 ppt). At the same time, R. mucronata showed comparatively higher lignin content (101.4–149.6 µg/mg) than K. candel (40.6–145.1 µg/mg). Total pectin concentration increased after 60 days in K. candel at freshwater (55.7–199.82 µg/mg) and salt treatments (90.0–210.5 µg/mg at 20 ppt). But pectin content decreased after 60 days of treatment in R. mucronata. A similar trend was observed for total carbohydrates and cellulose. Overall, hemicellulose concentration was low in R. mucronata compared to K. candel. Total polyphenol content was higher in R. mucronata (308.1–731.1 µg GAE/mg DW) than in K. candel (43.1–400.4 µg GAE/mg DW). Higher gene expression of lignin biosynthesis genes viz CAD, HCT, C3H, COMT and peroxidase was observed in R. mucronata at 5 ppt salinity 60 days after treatment. The results of this study will help explain the role of root lignification in mangrove salinity tolerance mechanisms. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of melatonin treatment on inhibiting lignification and browning, including firmness, lignin content, enzyme activities, and the expression level of genes encoding corresponding enzymes in bamboo (Acidosasa edulis) shoots without sheaths during cold storage were investigated. Bamboo shoots without physical injuries or infections and similar in shape and size were removed from their sheaths and cleaned with tap water and then disinfected with 150 μL/L sodium hypochlorite for 5 min, rinsed with tap water, and air-dried. The bamboo shoots were soaked in 0.2 mmol/L melatonin solution and water (control) (both containing 0.05% Tween-80 and 3 mL anhydrous ethanol) at 22 ℃ for 30 minutes, air-dried at room temperature for approximately 60 min and subsequently stored at 6±1 °C accompanied by 75%~80% RH for 15 days. Quality parameters and activities of key enzymes and gene expression involved in lignification and browning of bamboo shoots were periodically determined during cold storage to investigate the related mechanism. The results showed that melatonin treatment significantly (P

In this study, the regulatory effect of near-freezing temperature (NFT) storage on postharvest lignification of Dendrocalamus brandisii shoots was evaluated. Samples stored at room temperature and 4 ℃ served as controls. Respiratory intensity, mass loss rate, hardness, H2O2 content, lignin content, and the activities and gene expression of key enzymes involved in lignin synthesis were measured during storage. The results showed that compared with the controls, NFT storage significantly inhibited the increase of respiration intensity, mass loss, hardness, H2O2 content and lignin content in D. brandisii shoots, and delayed the increase of phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), cinnamate 4-hydroxylase (C4H), and peroxidase (POD) activities. Transcriptomic analysis showed that 33 genes members in PAL, 4CL, HCT, CCR, and CAD families were down-regulated and 25 gene members were up-regulated. Correlation analysis revealed that most physiological indexes and the activities and gene expression of key enzymes involved in lignin synthesis were significantly and positively correlated with the lignin content. In conclusion, NFT storage could effectively suppress the lignification of D. brandisii shoots during storage by regulating the respiratory intensity, mass loss rate, hardness, H2O2 content, lignin content, and key enzyme activities and gene expression related to lignin synthesis.

Abstract Background The phenolic polymer lignin is one of the primary chemical constituents of the plant secondary cell wall. Due to the inherent plasticity of lignin biosynthesis, several phenolic monomers have been shown to be incorporated into the polymer, as long as the monomer can undergo radicalization so it can participate in coupling reactions. In this study, we significantly enhance the level of incorporation of monolignol ferulate conjugates into the lignin polymer to improve the digestibility of lignocellulosic biomass. Results Overexpression of a rice Feruloyl-CoA Monolignol Transferase (FMT), OsFMT1, in hybrid poplar (Populus alba x grandidentata) produced transgenic trees clearly displaying increased cell wall-bound ester-linked ferulate, p-hydroxybenzoate, and p-coumarate, all of which are in the lignin cell wall fraction, as shown by NMR and DFRC. We also demonstrate the use of a novel UV–Vis spectroscopic technique to rapidly screen plants for the presence of both ferulate and p-hydroxybenzoate esters. Lastly we show, via saccharification assays, that the OsFMT1 transgenic p oplars have significantly improved processing efficiency compared to wild-type and Angelica sinensis-FMT-expressing poplars. Conclusions The findings demonstrate that OsFMT1 has a broad substrate specificity and a higher catalytic efficiency compared to the previously published FMT from Angelica sinensis (AsFMT). Importantly, enhanced wood processability makes OsFMT1 a promising gene to optimize the composition of lignocellulosic biomass.

SUMMARY: Analysis of salinity tolerance processes in wheat has focused on salt exclusion from shoots while root phenotypes have received limited attention. Here, we consider the varying phenotypic response of four bread wheat varieties that differ in their type and degree of salt tolerance and assess their molecular responses to salinity and changes in root cell wall lignification. These varieties were Westonia introgressed with Nax1 and Nax2 root sodium transporters (HKT1;4‐A and HKT1;5‐A) that reduce Na+ accumulation in leaves, as well as the 'tissue tolerant' Portuguese landrace Mocho de Espiga Branca that has a mutation in the homologous gene HKT1;5‐D and has high Na+ concentration in leaves. These three varieties were compared with the relatively more salt‐sensitive cultivar Gladius. Through the use of root histochemical analysis, ion concentrations, as well as differential proteomics and targeted metabolomics, we provide an integrated view of the wheat root response to salinity. We show different metabolic re‐arrangements in energy conversion, primary metabolic machinery and phenylpropanoid pathway leading to monolignol production in a genotype and genotype by treatment‐dependent manner that alters the extent and localisation of root lignification which correlated with an improved capacity of wheat roots to cope better under salinity stress. [ABSTRACT FROM AUTHOR]

Okra (Abelmoschus esculentus (L.) Moench) pod storage is challenging due to its high water content and tendency to lignify. Sodium hydrosulfide (NaHS) served as an H2S donor in this investigation. Compared with the control group, the group treated with 0.5 mmol/L NaHS solution effectively maintained the appearance quality, and its weight loss was only 6.21% at 20 days. The H2S treatment not only preserved tissue nutrients but also significantly enhanced catalase (CAT), ascorbic acid peroxidase (APX), and superoxide dismutase (SOD) activities while decreasing oxidant damage. In addition, H2S slowed down lignin synthesis by inhibiting the activities of key enzymes such as phenylalanine ammonialyase (PAL), cinnamate 4-hydroxylase (C4H), and cinnamyl alcohol dehydrogenase (CAD) in the lignin biosynthesis pathway. Transcriptome analysis revealed that H2S affects 34 genes in the phenylpropanoid biosynthesis pathway, such as AePAL, Ae4CL1, AeCCOAOMT1, AePOD, etc., which inhibit lignin synthesis of okra pods. All in all, moderate H2S can improve postharvest quality and extend the shelf-life of okra pods by enhancing antioxidant capacity and delaying lignification; the results will provide an overview of its application in the preservation of okra pods. [ABSTRACT FROM AUTHOR]

Summary: Plant secreted peptides RAPID ALKALINISATION FACTORs (RALFs), which act through the receptor FERONIA (FER), play important roles in plant growth. However, it remains unclear whether and how RALF‐FER contributes to the trade‐off of plant growth–defense.Here, we used a variety of techniques such as CRISPR/Cas9, protein–protein interaction and transcriptional regulation methods to investigate the role of RALF2 and its receptor FER in regulating lignin deposition, root growth, and defense against Fusarium oxysporum f. sp. lycopersici (Fol) in tomato (Solanum lycopersicum).The ralf2 and fer mutants show reduced primary root length, elevated lignin accumulation, and enhanced resistance against Fol than the wild‐type. FER interacts with and phosphorylates MYB63 to promote its degradation. MYB63 serves as an activator of lignin deposition by regulating the transcription of dirigent protein gene DIR19. Mutation of DIR19 suppresses lignin accumulation, and reverses the short root phenotype and Fol resistance in ralf2 or fer mutant.Collectively, our results demonstrate that the RALF2‐FER‐MYB63 module fine‐tunes root growth and resistance against Fol through regulating the deposition of lignin in tomato roots. The study sheds new light on how plants maintain the growth–defense balance via RALF‐FER. [ABSTRACT FROM AUTHOR]

Anther dehiscence is a crucial event in plant reproduction, tightly regulated and dependent on the lignification of the anther endothecium. In this study, we investigated the rapid lignification process that ensures timely anther dehiscence in Arabidopsis. Our findings reveal that endothecium lignification can be divided into two distinct phases. During Phase I, lignin precursors are synthesized without polymerization, while Phase II involves simultaneous synthesis of lignin precursors and polymerization. The transcription factors MYB26, NST1/2, and ARF17 specifically regulate the pathway responsible for the synthesis and polymerization of lignin monomers in Phase II. MYB26‐NST1/2 is the key regulatory pathway responsible for endothecium lignification, while ARF17 facilitates this process by interacting with MYB26. Interestingly, our results demonstrate that the lignification of the endothecium, which occurs within approximately 26 h, is much faster than that of the vascular tissue. These findings provide valuable insights into the regulation mechanism of rapid lignification in the endothecium, which enables timely anther dehiscence and successful pollen release during plant reproduction. [ABSTRACT FROM AUTHOR]

This study develops the use of ‘blue rings’ (BR), reflecting incomplete cell wall lignification, as a sensitive thermal indicator in bristlecone pine (Pinus longaeva D.K. Bailey). Using double-stained anatomical thin-sections, we explore the climatic and topographical constraints governing BR formation by developing a time-series from 83 cores and comparing BR occurrence with the full temporal span of available climatic data (1895–2008 CE). Lignification is temperature-dependent and continues at a cellular level post-radial growth completion. As BRs reflect incomplete lignification, they can serve as a higher resolution and more sensitive proxy for past cooling than previously established tree-growth indicators. Results indicate that blue ring formation is primarily induced by low September temperatures and responds more sensitively to cooling than the well-established frost-ring record. Additionally, the occurrence and intensity of blue rings decreases gradually below the upper tree line. Bristlecone pine BRs are demonstrated to have significant capacity to enhance the reconstruction of past cooling events in North America connected with both localized and hemispheric scale forcing over multi-millennial timescales. Given its unmatched longevity, the species offers an unparalleled potential for Holocene length climate reconstruction. Findings also highlight the potential for blue rings to provide a more nuanced understanding of past temperature fluctuations across multi-millennial timescales. [ABSTRACT FROM AUTHOR]

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 characteristics. The nematicidal and attractive metabolite of A. tubingensis WF01 was identified as oxalic acid (OA), which showed solid nematicidal activity against M. incognita, having LC50 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. [ABSTRACT FROM AUTHOR]

Background: The phenolic polymer lignin is one of the primary chemical constituents of the plant secondary cell wall. Due to the inherent plasticity of lignin biosynthesis, several phenolic monomers have been shown to be incorporated into the polymer, as long as the monomer can undergo radicalization so it can participate in coupling reactions. In this study, we significantly enhance the level of incorporation of monolignol ferulate conjugates into the lignin polymer to improve the digestibility of lignocellulosic biomass. Results: Overexpression of a rice Feruloyl-CoA Monolignol Transferase (FMT), OsFMT1, in hybrid poplar (Populus alba x grandidentata) produced transgenic trees clearly displaying increased cell wall-bound ester-linked ferulate, p-hydroxybenzoate, and p-coumarate, all of which are in the lignin cell wall fraction, as shown by NMR and DFRC. We also demonstrate the use of a novel UV–Vis spectroscopic technique to rapidly screen plants for the presence of both ferulate and p-hydroxybenzoate esters. Lastly we show, via saccharification assays, that the OsFMT1 transgenic p oplars have significantly improved processing efficiency compared to wild-type and Angelica sinensis-FMT-expressing poplars. Conclusions: The findings demonstrate that OsFMT1 has a broad substrate specificity and a higher catalytic efficiency compared to the previously published FMT from Angelica sinensis (AsFMT). Importantly, enhanced wood processability makes OsFMT1 a promising gene to optimize the composition of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Tender bamboo shoots undergo rapid senescence that influences their quality and commercial value after harvest. In this study, the tender sweet bamboo shoots ('Wensun') were packed by a passive modified atmosphere packaging (PMAP) to inhibit the senescence process, taking polyethylene package as control. The increase in CO2 and the decrease in O2 gas concentrations in the headspace atmosphere of the packages were remarkably modified by PMAP treatments. The modified gas atmosphere packaging inhibited the changes in firmness, as well as the content of cellulose, total pectin, and lignin in the cell walls of bamboo shoots. The enzymatic activities of cellulase, pectinase, and polygalacturonase that act on cell wall polysaccharides, and phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, peroxidase, and laccase regulating the lignin biosynthesis were modified by PMAP treatment different from control during storage. The expression levels of the lignin biosynthesis genes PePAL3/4, PeCAD, Pe4CL5, PeC4H, PeCCOAOMT, PeCOMT, cellulose synthase PeCESA1, and related transcription factors PeSND2, PeKNAT7, PeMYB20, PeMYB63, and PeMYB85 were clearly regulated. These results suggest that PMAP efficiently retards the changes in lignin and cell wall polysaccharides, thus delaying the senescence of tender sweet bamboo shoots during storage. [ABSTRACT FROM AUTHOR]

SUMMARY: The increased soil salinity is becoming a major challenge to produce more crops and feed the growing population of the world. In this study, we demonstrated that overexpression of OsDIR55 gene enhances rice salt tolerance by altering the root diffusion barrier. OsDIR55 is broadly expressed in all examined tissues and organs with the maximum expression levels at lignified regions in rice roots. Salt stress upregulates the expression of OsDIR55 gene in an abscisic acid (ABA)‐dependent manner. Loss‐function and overexpression of OsDIR55 compromised and improved the development of CS and root diffusion barrier, manifested with the decreased and increased width of CS, respectively, and ultimately affected the permeability of the apoplastic diffusion barrier in roots. OsDIR55 deficiency resulted in Na+ accumulation, ionic imbalance, and growth arrest, whereas overexpression of OsDIR55 enhances salinity tolerance and provides an overall benefit to plant growth and yield potential. Collectively, we propose that OsDIR55 is crucial for ions balance control and salt stress tolerance through regulating lignification‐mediated root barrier modifications in rice. Significance Statement: Collectively, we propose that OsDIR55 is crucial for ions balance control and salt stress tolerance through regulating lignification‐mediated root barrier modifications in rice. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of vacuum precooling treatment on the lignification of Tricholoma matsutake during storage, the changes in the hardness of cap and stalk, pulp firmness, lignin, chitin and cellulose contents, and the activities of cellulase (CX), phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) were studied during storage. The results showed that compared with the control group, vacuum precooling treatment could significantly inhibit the decline in the hardness of cap and stalk and pulp firmness, effectively inhibit the degradation of chitin and the increase of CX activity in the cell wall, maintain a higher cellulose content, and delay the accumulation of lignin. In addition, it could decrease the peak PAL activity of cap and stalk by 8.2% and 2.9%, the peak POD activity by 10% and 3.7%, and the peak PPO activity by 23.1% and 5.2%, respectively. In addition, compared with the cap, the peak time of lignification in the stalk was earlier, and lignification phenomenon was more likely to occur in the stalk. Therefore, vacuum precooling treatment can delay the lignification process and maintain the quality of T. matsutake.

The process of silique dehiscence is essential for the proper dispersal of seeds at the end of a dehiscent fruit plants lifecycle. Current research focuses on genetic manipulation to mitigate this process and enhance shatter tolerance in crop plants, which has significant economic implications. In this study, we have conducted a time-course analysis of cell patterning and development in valve tissues of Arabidopsis thaliana and closely related Triangle of U species (Brassica juncea, Brassica carinata, Brassica napus, Brassica rapa, and Brassica nigra) from Brassicaceae. The goal was to decipher the detailed temporal developmental patterns of the endocarp a and b cell layers of the valve, specifically their degradation and lignification respectively. Additionally, we propose a new classification system for the lignification of the endocarp a cell layer: L1 indicates the cell closest to the replum, with L2 and L3 representing the second and third cells, respectively, each numerical increment indicating lignified cells farther from the replum. Our findings provide a foundational framework absent in current literature, serving as an effective blueprint for future genomic work aimed at modifying valve structures to enhance agronomic traits, such as reducing fiber (lignin) or increasing shatter tolerance.

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Current infrared spectroscopy applications in the field of viticulture are moving toward direct in-field measuring techniques. However, limited research is available on quantitative applications using direct measurement of fresh tissue. The few studies conducted have combined the spectral data from various cultivars, growing regions, grapevine organs, and phenological stages during model development. The spectral data from these heterogeneous samples are combined into a single data set and analyzed jointly during quantitative analysis. Combining the spectral information of these diverse samples into a global data set could be an unsuitable approach and could yield less accurate prediction results. Spectral differences among samples could be overlooked during model development and quantitative analysis. The development of specialized calibrations should be considered and could lead to more accurate quantitative analyses. This study explored a model optimization strategy attempting global and specialized calibrations. Global calibrations, containing data from multiple organs, berry phenological, and shoot lignification stages, were compared to specialized calibrations per organ or stage. The global calibration for organs contained data from shoots, leaves, and berries and produced moderately accurate prediction results for nitrogen, carbon, and hydrogen. The specialized calibrations per organ yielded more accurate calibrations with a coefficient of determination in validation (R2val) at 90.65% and a root mean square error of prediction (RMSEP) at 0.32% dry matter (DM) for the berries' carbon calibrations. The leaves and shoots carbon calibrations had R2val and RMSEP at 84.99%, 0.34% DM, and 90.06%, 0.37% DM, respectively. The specialized calibrations for nitrogen and hydrogen showed similar improvements in prediction accuracy per organ. Specialized calibrations per phenological and lignification stage were also explored. Not all stages showed improvement, however, most stages had comparable or improved results for the specialized calibrations compared to the global calibrations containing all phenological or lignification stages. The results indicated that both global and specialized calibrations should be considered during model development to optimize prediction accuracy. [ABSTRACT FROM AUTHOR]

This study focused on the "Xinlu" walnut and explored the molecular regulatory mechanism of lignin synthesis in the endocarp, aiming to explain the formation of bared-nut walnuts through morphological, metabolomic, and transcriptomic techniques. It was found that the synthesis of lignin, cellulose, p-coumaryl alcohol, and sinapyl alcohol was severely inhibited in the pulpy-hue (PUH) of the endocarp. We obtained 14 modules (gene sets) significantly correlated with the lignification factor (LIG) and 1548 hub genes. Additionally, we identified a MEplum3 module involved in endocarp lignin synthesis, primarily participating in phenylalanine biosynthesis and the lignin biosynthetic process. Meanwhile, we constructed a gene co-expression network for the MEplum3 module and identified a key hub gene for lignin synthesis—JrCAD10. Among the different tissues of "Xinlu", the expression level of JrCAD10 in the scleritic-hue (SCH) was significantly higher than in other tissues, with a relative copy number (RCN) of 3.2. However, JrCAD10 expression was severely suppressed in the PUH. The suppression of JrCAD10 expression led to the inhibition of lignin monomer synthesis, which further resulted in inhibited lignin synthesis, thus forming the bared-nut walnut. Our findings provide new insights into understanding the regulation of lignin synthesis and offer a possible explanation for the formation of bared-nut walnuts. [ABSTRACT FROM AUTHOR]

Ridging cultivation and root restriction cultivation are beneficial due to their improvement of the soil permeability in the root zone of grapevine, and they are widely used in southern China, Japan, and other countries. However, with the intensification of global warming, when using ridging or root restriction cultivation, the soil temperature in the root zone can often reach 30 °C or even more than 35 °C during the summer, which is not conducive to the growth of grapevines. The aim of this study was to explore the effects of high root zone temperatures on the photosynthetic fluorescence characteristics of grapevine leaves, root respiration, and degree of lignification of roots and shoots, as well as to provide a theoretical foundation for the management of grapevine production and cultivation. One-year-old potted 'Kyoho' was used as the study material. Three root temperature treatments were implemented for 15 days (9:00–16:00): 25 °C (CK), 30 °C (T1), and 35 °C (T2). The results showed that the malondialdehyde and H2O2 levels in leaves increased, while the chlorophyll content decreased. The oxygen-evolving complex was inactivated, and PSII donor and acceptor sides were blocked, thus reducing the photosynthetic gas exchange capacity at high root zone temperatures. The grapevine root activity and root/shoot ratio decreased. Simultaneously, the lignin content in the roots and shoots increased. In addition, there was a significant increase in the expression of key genes (PAL, C4H, 4CL, F5H, COMT, CCR, and CAD) in the root lignin synthesis pathway. Heightened root zone temperatures increased cyanide-resistant respiration in roots and heat release in the PPP pathway to alleviate stress damage. Therefore, it is recommended to use grass, mulching, and other cultivation management methods to maintain root zone temperatures below 30 °C in order to ensure the normal growth of grapevines and promote a high and stable yield. [ABSTRACT FROM AUTHOR]

In order to explore the changing of lignin in bamboo shoots, the Phyllostachys praecox were stored at room temperature (25 °C) and low temperature (4 °C), and the enzyme activity and relative gene expression related to changes in lignin content and components were studied. The results showed that: at room temperature, the bamboo shoots showed changes such as yellowing and decay after stored for 6 days; under low temperature storage conditions, the bamboo shoots showed yellowing and decay until the 24th day. Stored at low temperature for 6 days, the lignin content was 13.22 mg/g, and increased to 26.31 mg/g on the 24th day. The total amount of amino acids did not change much under low- temperature storage conditions, and it showed a slow downward trend at room temperature. On the 6th day, the amino acids decreased by 21.78% at the room-temperature storage. Enzyme activities such as phenylalanine ammonia lyase (PAL), peroxidase (POD), cinnamyl alcohol dehydrogenase (CAD), and cinnamic acid-4-hydroxylase (C4H) showed a significant upward trend with extending storage time. Enzyme activities under room temperature storage were higher than those under low temperature storage. Low temperature reduced the activity of bamboo fiber-related enzymes by inhibiting the expression of genes related to bamboo lignin formation, thereby slowing down the process of lignification. Under the low temperature, the number of genes related to down-regulated expression increased with the extending of storage time. The most significant down-regulation of genes were observed at 24 d, while the amount of up-regulated genes was relatively small, with the smallest number observed at 12 d. The relative expression levels of LAC-10, P0D-10, HCT-10, CAD-10, and CCR-10 genes showed an overall upward trend under low temperature storage, while the relative expression level of C0MT-10 gene decreased continuously. This study provides a theoretical basis for controlling post-harvest quality of bamboo shoots. [ABSTRACT FROM AUTHOR]

【Objective】Fresh bamboo shoots are bamboo shoot products that have not been blanched or pickled, with a crispy taste and refreshing flavor. However, fresh bamboo shoots breathe vigorously, which are prone to dehydration and wilting, making them difficult to keep fresh, thus affecting their sales. Spontaneous modified atmosphere packaging reduces the respiratory intensity of packaged fruits and vegetables by regulating the gas composition of the internal environment. Studying the effects of different modified atmosphere packaging treatments on the postharvest storage quality and lignification of fresh bamboo shoots could provide references for the selection of fresh-keeping packaging for fresh bamboo shoots.【Method】The peeled fresh bamboo shoots were packed in the spontaneous modified atmosphere preservation bag (thickness 20μm, O2transmission rate 11 643 cm3/m2·d·atm, water vapor transmission rate 62.586 g/m2·d), and the vacuum bag made of nylon was used as control. The packaged fresh bamboo shoots were stored in the cold storage to study the quality change and the difference of lignification degree during storage.【Result】Compared with traditional vacuum preservation techniques, spontaneous modified atmosphere packaging could significantly reduce the respiratory intensity of fresh bamboo shoots during storage by creating a low oxygen and low carbon dioxide(O2 < 5%, CO2 < 5%) environment inside the bag through the respiration of the bamboo shoots themselves and the gas permeability of the membrane material. The peak intensity was only 46.93% of that of vacuum treatment. After 21 days of storage, modified atmosphere packaging significantly inhibited the browning and membrane lipid peroxidation of bamboo shoots. The brightness of the core of packaged bamboo shoots decreased by only 6.17% compared with that upon harvest, while that of vacuum packaging decreased by 17.74%. The content of malondialdehyde in vacuum packaged bamboo shoots was 2.93 times that in modified atmosphere packaging. In terms of lignification, the lignification rates of bamboo shoots in two types of packaging began to increase after 14 days of storage. The activities of key enzymes for lignification of bamboo shoots (phenylalanine ammonia lyase, peroxidase, cinnamon dehydrogenase) peaked in vacuum packaging, and lignification intensified; however, there was no peak in the related enzyme activity of bamboo shoots in the modified atmosphere packaging, and the enzyme activity increased slowly, delaying the lignification of bamboo shoot and maintaining the crisp taste of the bamboo shoots. After 21 days of storage, the lignin content of packaged bamboo shoots decreased by 15.01% compared to vacuum packaged bamboo shoots, effectively extending the freshness period of fresh bamboo shoots.【Conclusion】The low oxygen and low carbon dioxide gas environment in the spontaneous modified atmosphere packaging bag is conducive to the storage of fresh bamboo shoots, and the quality and nutrient content are significantly better than those of vacuum packaging treatment. It has a good market prospect for fresh bamboo shoots.

[Objective] Fresh bamboo shoots are bamboo shoot products that have not been blanched or pickled, with a crispy taste and refreshing flavor. However, fresh bamboo shoots breathe vigorously, which are prone to dehydration and wilting, making them difficult to keep fresh, thus affecting their sales. Spontaneous modified atmosphere packaging reduces the respiratory intensity of packaged fruits and vegetables by regulating the gas composition of the internal environment. Studying the effects of different modified atmosphere packaging treatments on the postharvest storage quality and lignification of fresh bamboo shoots could provide references for the selection of fresh-keeping packaging for fresh bamboo shoots. [Method] The peeled fresh bamboo shoots were packed in the spontaneous modified atmosphere preservation bag (thickness 20 μm, O2 transmission rate 11 643 cm³ /m² ·d·atm, water vapor transmission rate 62.586 g/m² ·d), and the vacuum bag made of nylon was used as control. The packaged fresh bamboo shoots were stored in the cold storage to study the quality change and the difference of lignification degree during storage. [Result] Compared with traditional vacuum preservation techniques, spontaneous modified atmosphere packaging could significantly reduce the respiratory intensity of fresh bamboo shoots during storage by creating a low oxygen and low carbon dioxide (O2 <5%, CO2 <5%) environment inside the bag through the respiration of the bamboo shoots themselves and the gas permeability of the membrane material. The peak intensity was only 46.93% of that of vacuum treatment. After 21 days of storage, modified atmosphere packaging significantly inhibited the browning and membrane lipid peroxidation of bamboo shoots. The brightness of the core of packaged bamboo shoots decreased by only 6.17% compared with that upon harvest, while that of vacuum packaging decreased by 17.74%. The content of malondialdehyde in vacuum packaged bamboo shoots was 2.93 times that in modified atmosphere packaging. In terms of lignification, the lignification rates of bamboo shoots in two types of packaging began to increase after 14 days of storage. The activities of key enzymes for lignification of bamboo shoots (phenylalanine ammonia lyase, peroxidase, cinnamon dehydrogenase) peaked in vacuum packaging, and lignification intensified; however, there was no peak in the related enzyme activity of bamboo shoots in the modified atmosphere packaging, and the enzyme activity increased slowly, delaying the lignification of bamboo shoot and maintaining the crisp taste of the bamboo shoots. After 21 days of storage, the lignin content of packaged bamboo shoots decreased by 15.01% compared to vacuum packaged bamboo shoots, effectively extending the freshness period of fresh bamboo shoots. [Conclusion] The low oxygen and low carbon dioxide gas environment in the spontaneous modified atmosphere packaging bag is conducive to the storage of fresh bamboo shoots, and the quality and nutrient content are significantly better than those of vacuum packaging treatment. It has a good market prospect for fresh bamboo shoots. [ABSTRACT FROM AUTHOR]

The length of internodes plays a crucial role in determining the height of the castor plant (Ricinus communis L.). However, the specific mechanisms underlying internode elongation, particularly in the main stem of the castor plant, remain uncertain. To further investigate this, we conducted a study focusing on the internode tissue of the dwarf castor variety 071113, comparing it with the control high-stalk Zhuansihao. Our study included a cytological observation, physiological measurement, transcriptome sequencing, and metabolic determination. Our integrated findings reveal that the dwarf variety 071113 undergoes an earlier lignification development in the main stem and has a more active lignin synthesis pathway during internode intermediate development. In addition, the dwarf variety exhibited lower levels of the plant hormone indole-3-acetic acid (IAA), which had an impact on the development process. Furthermore, we identified specific enzymes and regulators that were enriched in the pathways of the cell cycle, auxin signal transduction, and secondary cell wall synthesis. Using these findings, we developed a model that explained the intermediate secondary growth observed in castor internode elongation and enhanced our comprehension of the dwarfing mechanism of the 071113 variety. This research provides a theoretical groundwork for the future breeding of dwarf castor varieties. [ABSTRACT FROM AUTHOR]

According to modern phylogenetic data, the monotypic subfamily Enkianthoideae is sister to all other subfamilies of the family Ericaceae s.l. Aiming to determine the peculiarities of development and structure of Enkianthus pericarp and to reveal the principal characters of its structure, which can be original for the Ericaceae, we have studied fruit anatomical structure at different stages of development in four species of the genus Enkianthus belonging to three sections: Meisteria , Enkiantella , Enkianthus. The pericarp of superior loculicidal capsule of Enkianthus is differentiated into three histogenetic zones: (i) one-layered exocarp, (ii) multilayered mesocarp differentiated into two histological zones: the peripheral parenchymatous one, and the inner sclerenchymatous one, and (iii) one-layered endocarp composed of tangentially elongated sclereids. It has been shown that the lignification of cells of the endocarp proceeds after the lignification of the inner zone of the mesocarp. Our investigation demonstrates that the superior loculicidal capsules of Enkianthus are capsules of Hamamelis type, which are recognized as the probable ancestral (plesiomorphic) fruit type for other subfamilies of Ericaceae. This fruit type is recognized as the original in several modes of morphogenetic transformations of fruit in Ericaceae family, from which other types of capsules, pyrenariums, and berries originated. [ABSTRACT FROM AUTHOR]

Main conclusion: Transcriptional and metabolic regulation of lignin biosynthesis and lignification plays crucial roles in Avicennia marina pneumatophore development, facilitating its adaptation to coastal habitats. Avicennia marina is a pioneer mangrove species in coastal wetland. To cope with the periodic intertidal flooding and hypoxia environment, this species has developed a complex and extensive root system, with its most unique feature being a pneumatophore with a distinct above- and below-ground morphology and vascular structure. However, the characteristics of pneumatophore lignification remain unknown. Studies comparing the anatomy among above-ground pneumatophore, below-ground pneumatophore, and feeding root have suggested that vascular structure development in the pneumatophore is more like the development of a stem than of a root. Metabolome and transcriptome analysis illustrated that the accumulation of syringyl (S) and guaiacyl (G) units in the pneumatophore plays a critical role in lignification of the stem-like structure. Fourteen differentially accumulated metabolites (DAMs) and 10 differentially expressed genes involved in the lignin biosynthesis pathway were targeted. To identify genes significantly associated with lignification, we analyzed the correlation between 14 genes and 8 metabolites and further built a co-expression network between 10 transcription factors (TFs), including 5 for each of MYB and NAC, and 23 enzyme-coding genes involved in lignin biosynthesis. 4-Coumarate-CoA ligase, shikimate/quinate hydroxycinnamoyl transferase, cinnamyl alcohol dehydrogenase, caffeic acid 3-O-methyltransferase, phenylalanine ammonia-lyase, and peroxidase were identified to be strongly correlated with these TFs. Finally, we examined 9 key candidate genes through quantitative real-time PCR to validate the reliability of transcriptome data. Together, our metabolome and transcriptome findings reveal that lignin biosynthesis and lignification regulate pneumatophore development in the mangrove species A. marina and facilitate its adaptation to coastal habitats. [ABSTRACT FROM AUTHOR]

In recent years, some new Qi-Nan clones of Aquilaria sinensis, which have the characteristics of easily induced and high-quality agarwood, have been selected and propagated by grafting seedlings. To date, research on the grafting of Qi-Nan seedlings is limited. In this study, the effects of grafting on physiological characteristics and endophytic fungi of seedlings within a short period after grafting were studied by means of histochemical observations, physiological index determinations and Illumina sequencing. The results showed that the grafting healing time of ordinary A. sinensis was at least 10 days shorter than that of Qi-Nan, according to the degree of lignification of callus, and the tissue basis for the healing was the interxylary phloem. The MDA content of Qi-Nan peaked earlier than that of ordinary A. sinensis. The contents of JA and ABA peaked earlier in ordinary A. sinensis, and the SA content was significantly higher than that of Qi-Nan at 20–40 days; on average, it was 17.33% higher than that of Qi-Nan. A total of 5 phyla, 28 classes, 84 orders, 197 families, 489 genera and 842 species of endophytic fungi were identified before and after grafting. After grafting, the abundance and diversity of endophytic fungi in ordinary A. sinensis and Qi-Nan decreased, and the endophytic fungi were significantly different before and after grafting. In ordinary A. sinensis, before grafting, Dothideomycetes was the dominant class, and after grafting, Sordariomycetes was the dominant class. The dominant class of Qi-Nan before and after grafting was Dothideomycetes. The dominant genus of ordinary A. sinensis before grafting was Devriesia, and after grafting, it was Fusarium; that of Qi-Nan before grafting was Hyweljonesia and after grafting was Arthopyrenia. Functional genes of the endophytic fungi were mostly related to carbohydrate metabolism and energy metabolism, which may be the reason why endophytic fungi promote agarwood formation in Aquilaria trees. The findings suggest that the healing of the grafting interface in A. sinensis seedlings was the result of multiple factors, and endophytic fungi of Qi-Nan scion changed after grafting. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) is considered as the most important forage legume with high biomass yield and nutritional quality for ruminants. The alfalfa leaf cell walls are highly digestible, but stem cell walls of alfalfa are not readily digestible. The cell wall component of alfalfa has a large source of dietary energy, but ruminant animals can digest less than half of this component due to the presence of high lignin content. The main goal of this review is to make a summary of existing knowledge of alfalfa cell wall thickening and lignification patterns and suggest future directions for improving alfalfa stem cell wall digestibility. We describe alfalfa cell wall biochemistry, alfalfa stem morphology, stem tissue degradation, and existing methods to improve alfalfa digestibility, and discuss the potential future strategies for improving alfalfa cell wall digestibility. Information on these will help alfalfa breeders and producers identify superior alfalfa cultivars with improved stem cell wall digestibility. Concentrating future efforts on the selection and identification of traits and associated genes that affect cell wall digestibility could improve alfalfa cell wall digestibility. [ABSTRACT FROM AUTHOR]

Phloem is the woody tissue for the storage and long-distance transport of organic matter in vascular bundles. To reveal the process of secondary phloem development and differentiation in Pinus massoniana, the structure of the secondary phloem and the distribution of cell inclusions were observed by histochemical staining, spontaneous fluorescence of phenolic substances and cell segregation. Based on tissue development and differentiation characteristics of P. massoniana secondary phloem, the secondary phloem development was divided into seven stages: the functional phloem stage; the sieve cell lignification stage; the phloem ray bending stage; the parenchyma cell dedifferentiation and division stage; the dedifferentiated parenchyma cell population formation stage; the periderm alteration stage, and the rhytidome stage. An analysis of cell morphology and inclusion distribution characteristics showed that the sieve cells were deformed during lignification, the quantities of parenchyma and resin ducts increased with development and the crystal content in cells, as well as the levels of sugars and lipids in phloem parenchyma cells, increased with development. The results indicate that the P. massoniana phloem first lost longitudinal transport function and then increased its secretory, storage and mechanical functions. Ultimately, the parenchyma differentiated into the cortex and periderm, and the tissue outside the new periderm lignified to form the rhytidome, which fully developed into the protective tissue of the stem. [ABSTRACT FROM AUTHOR]

Moso bamboo shoots, recognized as a green health food, are distinguished by their high protein, low fat, low sugar, and high fiber content. Their substantial nutritional value and appealing taste have made the product very popular with consumers. However, post-harvest, Phyllostachys edulis shoots are susceptible to rapid lignification. This paper explores the lignification process in Phyllostachys edulis at room temperature post-harvest. We assessed the physiological indices of four synthetic enzymes and their relative expression levels in lignin biosynthesis. Additionally, we investigated the correlation between the relative expression of lignin biosynthesis, enzyme activity, and lignin synthesis. Understanding the physiology of lignin biosynthesis in moso bamboo shoots post-harvest is crucial for comprehending their growth characteristics, benefiting production management, timely harvesting, and controlling the aging process to enhance economic value. The findings demonstrate that lignification in moso bamboo shoots progresses from the bottom to the top. At room temperature, the activities of PAL, POD, and 4CL enzymes, together with their expression in different parts of the moso bamboo shoots, exhibited a significant correlation with changes in lignin content. These enzymes are likely involved in lignin biosynthesis. The activity of the CAD enzyme in the bamboo shoot peaked at 2 hours, with CAD-related genes expressing the highest in the upper part at 10 hours, in the middle part at 2 hours, and in the lower part at 18 hours. Key message: The synthesis of lignin in moso bamboo shoots may be associated with PAL, POD, and 4CL.

Abstract Background Lodging seriously affects sugarcane stem growth and sugar accumulation, reduces sugarcane yield and sucrose content, and impedes mechanization. However, the molecular mechanisms underlying sugarcane lodging tolerance remain unclear. In this study, comprehensive transcriptomic and proteomic analyses were performed to explore the differential genetic regulatory mechanisms between upright (GT42) and lodged (GF98-296) sugarcane varieties. Results The stain test showed that GT42 had more lignin and vascular bundles in the stem than GF98-296. The gene expression analysis revealed that the genes that were differentially expressed between the two varieties were mainly involved in the phenylpropanoid pathway at the growth stage. The protein expression analysis indicated that the proteins that were differentially expressed between the two varieties were related to the synthesis of secondary metabolites, the process of endocytosis, and the formation of aminoacyl-tRNA. Time-series analysis revealed variations in differential gene expression patterns between the two varieties, whereas significant protein expression trends in the two varieties were largely consistent, except for one profile. The expression of CYP84A, 4CL, and CAD from the key phenylpropanoid biosynthetic pathway was enhanced in GT42 at stage 2 but suppressed in GF98-296 at the growth stage. Furthermore, the expression of SDT1 in the nicotinate and nicotinamide metabolism was enhanced in GT42 cells but suppressed in GF98-296 cells at the growth stage. Conclusion Our findings provide reference data for mining lodging tolerance-related genes that are expected to facilitate the selective breeding of sugarcane varieties with excellent lodging tolerance.

Abstract Background Peucedanum praeruptorum Dunn, a traditional Chinese herbal medicine, contains coumarin and volatile oil components that have clinical application value. However, early bolting often occurs in the medicinal materials of Apiaceae plants. The rhizomes of the medicinal parts are gradually lignified after bolting, resulting in a sharp decrease in the content of coumarins. At present, the link between coumarin biosynthesis and early bolting in P. praeruptorum has not been elucidated. Results Combining the genome sequencing and the previous transcriptome sequencing results, we reanalyzed the differential transcripts of P. praeruptorum before and after bolting. A total of 62,088 new transcripts were identified, of which 31,500 were unknown transcripts. Functional classification and annotation showed that many genes were involved in the regulation of transcription, defense response, and carbohydrate metabolic processes. The main domains are the pentatricopeptide repeat, protein kinase, RNA recognition motif, leucine-rich repeat, and ankyrin repeat domains, indicating their pivotal roles in protein modification and signal transduction. Gene structure analysis showed that skipped exon (SE) was the most dominant alternative splicing, followed by the alternative 3’ splice site (A3SS) and the alternative 5’ splice site (A5SS). Functional enrichment of differentially expressed genes showed that these differentially expressed genes mainly include transmembrane transporters, channel proteins, DNA-binding proteins, polysaccharide-binding proteins, etc. In addition, genes involved in peroxisome, hexose phosphate pathway, phosphatidylinositol signaling system, and inositol phosphate metabolism pathway were greatly enriched. A protein-protein interaction network analysis discoverd 1,457 pairs of proteins that interact with each other. The expression levels of six UbiA genes, three UGT genes, and four OMT genes were higher during the bolting stage. This observation suggests their potential involvement in the catalytic processes of prenylation, glycosylation, and methylation of coumarins, respectively. A total of 100 peroxidase (PRX) genes were identified being involved in lignin polymerization, but only nine PRX genes were highly expressed at the bolting stage. It is worth noting that 73 autophagy-related genes (ATGs) were first identified from the KEGG pathway-enriched genes. Some ATGs, such as BHQH00009837, BHQH00013830, and novel8944, had higher expression levels after bolting. Conclusions Comparative transcriptome analysis and large-scale genome screening provide guidance and new opinions for the identification of bolting-related genes in P. praeruptorum.

Okra (Abelmoschus esculentus (L.) Moench) pod storage is challenging due to its high water content and tendency to lignify. Sodium hydrosulfide (NaHS) served as an H2S donor in this investigation. Compared with the control group, the group treated with 0.5 mmol/L NaHS solution effectively maintained the appearance quality, and its weight loss was only 6.21% at 20 days. The H2S treatment not only preserved tissue nutrients but also significantly enhanced catalase (CAT), ascorbic acid peroxidase (APX), and superoxide dismutase (SOD) activities while decreasing oxidant damage. In addition, H2S slowed down lignin synthesis by inhibiting the activities of key enzymes such as phenylalanine ammonialyase (PAL), cinnamate 4-hydroxylase (C4H), and cinnamyl alcohol dehydrogenase (CAD) in the lignin biosynthesis pathway. Transcriptome analysis revealed that H2S affects 34 genes in the phenylpropanoid biosynthesis pathway, such as AePAL, Ae4CL1, AeCCOAOMT1, AePOD, etc., which inhibit lignin synthesis of okra pods. All in all, moderate H2S can improve postharvest quality and extend the shelf-life of okra pods by enhancing antioxidant capacity and delaying lignification; the results will provide an overview of its application in the preservation of okra pods.

An essential stage in the establishment of seed orchards is the formation of an optimal composition, avoiding inbreeding depression in the produced seed material, which develops as a result of crossbreeding between closely related plus trees. The negative effect can be reduced by ensuring the genetic heterogeneity of the seeds. The purpose of this study is to give a relative evaluation of the plus trees of Scots pine (Pinus sylvestris L.) as one of the most economically significant tree species on the European continent according to their physiological conditions. The formation and lignification of the xylem of the plus trees were investigated in the Nizhny Novgorod region of Russia. A histochemical examination was performed using the reaction of phloroglucinol to lignin. Phenotypic differences in the physiological conditions of plus trees appeared on a uniform ecological background that indicates their genotypic determinism. This fact was confirmed by ANOVA. The share of the influence of differences between the proper plus trees was between 25.16±8.91 % and 53.98±5.48 %. According to the results of the factor and cluster analysis, the association of plus trees was generated by the similarity of the multidimensional estimates of the xylem conditions. The objects that were statistically most distant from the others were determined. The hereditary conditionality of the identified differences among plus trees allows us to consider their grouping into clusters as genotypically determined. This information provides a reasonable approach to the formation of an assortment of Scots pine clonal seed orchards. For citation: Besschetnova N.N., Besschetnov V.P., Babich N.A., Bryntsev V.A. Differentiation of Plus Trees of Scots Pine by Xylem Conditions. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 9–25. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-9-25

Background: Lodging seriously affects sugarcane stem growth and sugar accumulation, reduces sugarcane yield and sucrose content, and impedes mechanization. However, the molecular mechanisms underlying sugarcane lodging tolerance remain unclear. In this study, comprehensive transcriptomic and proteomic analyses were performed to explore the differential genetic regulatory mechanisms between upright (GT42) and lodged (GF98-296) sugarcane varieties. Results: The stain test showed that GT42 had more lignin and vascular bundles in the stem than GF98-296. The gene expression analysis revealed that the genes that were differentially expressed between the two varieties were mainly involved in the phenylpropanoid pathway at the growth stage. The protein expression analysis indicated that the proteins that were differentially expressed between the two varieties were related to the synthesis of secondary metabolites, the process of endocytosis, and the formation of aminoacyl-tRNA. Time-series analysis revealed variations in differential gene expression patterns between the two varieties, whereas significant protein expression trends in the two varieties were largely consistent, except for one profile. The expression of CYP84A, 4CL, and CAD from the key phenylpropanoid biosynthetic pathway was enhanced in GT42 at stage 2 but suppressed in GF98-296 at the growth stage. Furthermore, the expression of SDT1 in the nicotinate and nicotinamide metabolism was enhanced in GT42 cells but suppressed in GF98-296 cells at the growth stage. Conclusion: Our findings provide reference data for mining lodging tolerance-related genes that are expected to facilitate the selective breeding of sugarcane varieties with excellent lodging tolerance. [ABSTRACT FROM AUTHOR]

Lignin is an important secondary metabolite that maintains the mechanical strength of horticultural plants and enhances their ability to respond to external environmental changes such as biotic and abiotic stresses. However, excessive accumulation of lignin can lead to lignification of horticultural products, reducing their taste quality and nutritional value. Therefore, the lignin content of horticultural products needs to be controlled at a reasonable level, and studying and regulating lignin metabolism is very meaningful work. This article focuses on the synthesis, accumulation, and regulation of lignin in horticultural crops in recent years, provides a systematic analysis of its molecular mechanism and application prospects, and sheds insights into the directions that need further research in the future. This article provides an important basis for the regulation of lignin accumulation and lignification in horticultural crops and proposes new ideas for improving the quality of horticultural crops. [ABSTRACT FROM AUTHOR]

Context: Agronomical traits like loss of seed dispersal targeted by ancient human selection are an important milestone of crop domestication. Evolution in plant species is a result of natural and human selection at the time of domestication. Evolution leads to continued improvement of adaptive traits in almost all plant species. Aims: Pod shattering, one of the examples of convergent evolution, is defined as breaking up of the pod shell enabling the successful dispersal of seeds mainly in wild species. Since the available climate change models predict an increase in aridity, it is expected that the losses on account of shattering will be aggravated, especially in dry areas. Methods: Histological studies and biochemical parameters are increasingly used as surrogates for pod shattering response as they provide key inputs for selecting contrasting genotypes based on differential lignification, role of pectin, fibre, cellulose and total carbohydrate content as well as enzymes such as endopolygalacturonase and β-glucanase and hormones. Key results: There is diversity for level of shattering, with race Nueva Granada showing higher rates of pod shattering as compared to the Durango and Jalisco races. Genomics has helped identify several genes or quantitative trait loci (QTL) such as PDH-1, St-1, SHAT-1, WRKY1 and MYB26 that are implicated in various traits related to pod shattering. Conclusions: Plant breeders need to introgress shattering resistance into commercial varieties to mitigate the imminent yield losses. Implications: This requires an in-depth knowledge of mechanistic, physiological, biochemical and the underlying genetic basis of pod shattering resistance. Common bean is an important legume crop that has long been used as a staple food. Pod shattering is an important early trait to be selected against in crop domestication. Introgression of shattering resistance into commercial varieties could mitigate the imminent yield losses. [ABSTRACT FROM AUTHOR]

Functionally similar to the tight junctions present in animal guts, plant roots have evolved a lignified Casparian strip as an extracellular diffusion barrier in the endodermis to seal the root apoplast and maintain nutrient homeostasis. How this diffusion barrier is structured has been partially defined, but its lignin polymerization and assembly steps remain elusive. Here, we characterize a family of dirigent proteins (DPs) essential for both the localized polymerization of lignin required for Casparian strip biogenesis in the cell wall and for attachment of the strip to the plasma membrane to seal the apoplast. We reveal a Casparian strip lignification mechanism that requires cooperation between DPs and the Schengen pathway. Furthermore, we demonstrate that DPs directly mediate lignin polymerization as part of this mechanism. [ABSTRACT FROM AUTHOR]

Metabolic changes under stress are often studied in short-term experiments, revealing rapid responses in gene expression, enzyme activity, and the amount of antioxidants. In a long-term experiment, it is possible to identify adaptive changes in both primary and secondary metabolism. In this study, we characterized the physiological state of tobacco plants and assessed the amount and spectrum of phenolic compounds and the lignification of axial organs under excess copper stress in a long-term experiment (40 days). Plants were treated with 100 and 300 μM CuSO4, as well as a control (Knop solution). Copper accumulation, the size and anatomical structure of organs, stress markers, and the activity of antioxidant enzymes were studied. Lignin content was determined with the cysteine-assisted sulfuric method (CASA), and the metabolite profile and phenolic spectrum were determined with UHPLC-MS and thin-layer chromatography (TLC). Cu2+ mainly accumulated in the roots and, to a lesser extent, in the shoots. Copper sulfate (100 μM) slightly stimulated stem and leaf growth. A higher concentration (300 μM) caused oxidative stress; H2O2 content, superoxide dismutase (SOD), and guaiacol peroxidase (GPOX) activity increased in roots, and malondialdehyde (MDA) increased in all organs. The deposition of lignin increased in the roots and stems compared with the control. The content of free phenolics, which could be used as substrates for lignification, declined. The proportions of ferulic, cinnamic, and p-coumaric acids in the hydrolysate of bound phenolics were higher, and they tended toward additional lignification. The metabolic profile changed in both roots and stems at both concentrations, and changed in leaves only at a concentration of 300 μM. Thus, changes in the phenolic spectrum and the enhanced lignification of cell walls in the metaxylem of axial (root and stem) organs in tobacco can be considered important metabolic responses to stress caused by excess CuSO4. [ABSTRACT FROM AUTHOR]

The blackening of cut carrots causes substantial economic losses to the food industry. Blackening was not observed in carrots that had been stored underground for less than a year, but the susceptibility to blackening increased with the age of the carrots that were stored underground for longer periods. Samples of black, border, and orange tissues from processed carrot batons and slices, prepared under industry standard conditions, were analyzed to identify the molecular and metabolic mechanisms underpinning processing-induced blackening. The black tissues showed substantial molecular and metabolic rewiring and large changes in the cell wall structure, with a decreased abundance of xyloglucan, pectins (homogalacturonan, rhamnogalacturonan-I, galactan and arabinan), and higher levels of lignin and other phenolic compounds when compared to orange tissues. Metabolite profiling analysis showed that there was a major shift from primary to secondary metabolism in the black tissues, which were depleted in sugars, amino acids, and tricarboxylic acid (TCA) cycle intermediates but were rich in phenolic compounds. These findings suggest that processing triggers a release from quiescence. Transcripts encoding proteins associated with secondary metabolism were less abundant in the black tissues, but there were no increases in transcripts associated with oxidative stress responses, programmed cell death, or senescence. We conclude that restraining quiescence release alters cell wall metabolism and composition, particularly regarding pectin composition, in a manner that increases susceptibility to blackening upon processing. [ABSTRACT FROM AUTHOR]

SUMMARY: The Casparian strip (CS) is a cell wall modification made of lignin that functions as an apoplastic barrier in the root endodermis to restrict nutrient and water transport between the soil and stele. CS formation is affected by nutritional conditions, and its physiological roles have been discussed. This study found that low K condition affects CS permeability, lignin deposition, and MYB36 mRNA accumulation. To understand the mechanism underlying these findings, we focused on nitric oxide (NO). NO is known to act as a signaling molecule and participates in cell wall synthesis, especially for lignin composition. However, the mechanism by which NO affects lignin deposition and corrects CS formation in the plant roots remains unclear. Through combining fluorescent observation with histological stains, we demonstrated that the root endodermal cell lignification response to low‐potassium (K) conditions is mediated by NO through the MYB36‐associated lignin‐polymerizing pathway. Furthermore, we discovered the noteworthy ability of NO to maintain nutrient homeostasis for adaptation to low K conditions by affecting the correct apoplastic barrier formation of CS. Collectively, our results suggest that NO is required for the lignification and apoplastic barrier formation in the root endodermis during adaptation to low K conditions, which revealing the novel physiological roles of CS under low nutrient conditions and making a significant contribution to CS biology. [ABSTRACT FROM AUTHOR]