Search Results (92)

Grafting is an important method for pecans, while the molecular mechanisms underlying graft union formation still need in-depth analysis. In the current investigation, we identified 22 BGLU genes in Carya illinoinensis (pecan) and demonstrated that CiBGLU21, a β-glucosidase-encoding gene, plays an important positive role in graft healing. The overexpression of CiBGLU21 enhanced graft survival rates and accelerated tissue regeneration, while biochemical assays confirmed its role in cell wall reinforcement and sugar metabolism. Additionally, we identified that CiWOX13 formed heterodimers with CiWOX14 to directly and synergistically activate the transcription of CiBGLU21. The current investigation revealed a CiWOX13/14-CiBGLU21 module as an important modulator of graft union formation, offering insights into improving grafting efficiency in perennial crops and advancing the understanding of cell wall dynamics during tissue regeneration. Full article

Pecan (Carya illinoinensis) cultivation generates a substantial number of byproducts, particularly nutshells, which are often discarded despite being rich in bioactive and structural compounds. These agro-industrial residues, comprising nearly 50% of the total nut mass, contain high levels of phenolics, flavonoids, dietary fiber, and lignocellulosic matter, making them suitable for circular economy applications. This review critically evaluates the potential of pecan shell waste for value-added applications in environmental remediation, food and pharmaceutical formulations, and green materials production. It explores innovative green extraction techniques, such as ultrasound-assisted, microwave-assisted, and subcritical water extraction, to recover valuable compounds like ellagic acid and tannins with high efficiency and minimal environmental impact. Moreover, the review highlights the conversion of pecan shells into activated carbon for wastewater treatment and soil remediation. Pecan byproducts have been used as sustainable feedstocks for catalyst support, contributing to energy conversion and biomass catalysis. The bioactive compounds also offer therapeutic properties, including antioxidant, anti-inflammatory, and antimicrobial effects, supporting their inclusion in nutraceutical and cosmetic applications. Through a comprehensive synthesis of recent studies, this work highlights the role of pecan shell valorization in reducing waste, improving public health, and increasing economic resilience within agro-industrial systems. By aligning with sustainable development and circular economies, the utilization of pecan byproducts provides a low-cost, eco-innovative pathway to mitigate environmental pollution and promote sustainable development. Full article

This study examines the influence of physical biomass pretreatment on the pyrolysis behavior of woody pruning residues of Carya illinoinensis (pecan tree) processed in a stainless-steel batch reactor heated by concentrated radiative energy. Experiments were conducted with 25.5 g of biomass using a solar simulator equipped with a mirror concentrator, operating at three constant thermal power levels (234, 482, and 725 W). As a pretreatment strategy, the woody residues were deliberately processed without drying, while mechanical size reduction and sieving were applied to obtain a controlled particle size range of 1–4 mm. This approach enabled the isolated assessment of the effects of physical pretreatment, particularly particle size and bulk density, on heat transfer, thermal response, and pyrolysis behavior. The pyrolysis performance of the pretreated woody biomass was systematically compared with that of walnut shell biomass and inert volcanic stones subjected to the same particle size control. Two consecutive experimental cases were implemented: Case A (CA), comprising heating, pyrolysis of fresh biomass, and cooling; and Case B (CB), involving reheating of the resulting biochar under identical operating conditions. An improved analytical methodology integrating temperature–time profiles, their derivatives, and gas composition analysis was employed. The results demonstrated the apparently inert thermal behavior of biochar during reheating and enabled clear temporal identification of the main biomass conversion stages, including drying, active pyrolysis of hemicellulose and cellulose, and passive lignin degradation. However, relative to walnut shell biomass of equivalent volume, the woody pruning residues exhibited attenuated thermal and reaction signals, primarily attributed to their lower bulk density resulting from the selected pretreatment conditions. This reduced bulk density led to less distinct pyrolysis stages and a 4.66% underestimation of the maximum reaction temperature compared with thermogravimetric analysis, highlighting the critical role of physical pretreatment in governing heat transfer efficiency and temperature measurement accuracy during biomass pyrolysis. Full article

Pecan is an important oilseed tree species valued for its nutrient-rich nuts. WRKY and VQ proteins play crucial roles in plant growth, development, and stress response. However, few WRKY and VQ genes in pecan have been functionally analyzed due to functional redundancy caused by gene duplication. In this study, 89 CiWRKYs and 47 CiVQs were identified in pecan genome, which were unevenly distributed across chromosomes. Gene structure and conserved motif analyses revealed high diversity among members. Duplication analysis indicated that segmental duplication was the major factor of family expansion of CiWRKY and CiVQ. Ka/Ks ratios revealed that most duplicated gene pairs underwent purifying selection. Promoter analysis identified numerous cis-acting elements associated with light response, hormone regulation, and abiotic stress, implying their potential regulatory roles in development and stress response. Expression data across six tissues demonstrated tissue-specific patterns, with several genes highly expressed in flowers and roots. Transcriptome analysis revealed that 63 CiWRKY and 27 CiVQ genes were significantly upregulated under drought stress. qRT-PCR validation confirmed that CiPaw.10G165200 and CiPaw.04G072500 were highly induced by salt treatment, with expression levels increasing over 100-fold at 8 d. Moreover, CiPaw.10G165200 was also highly expressed under ABA treatment, which indicated it might play a key role in the response to abiotic stresses. Our results provide valuable insights into the evolutionary patterns and functional roles of WRKY and VQ genes in pecan and lay a foundation for improving stress tolerance and molecular breeding in this economically important nut tree. Full article

This scoping review synthesized evidence from 2015 to 2025 on the anti-inflammatory and anticancer potential of pecan (Carya illinoinensis) kernel extracts, focusing on bioactive composition and cell signaling pathway modulation. Pecan kernels contain diverse phenolic compounds including gallic acid, catechin, epicatechin, and ellagic acid, along with tocopherols and unsaturated fatty acids, exhibiting significant cultivar-dependent variation influenced by ripening stage, processing conditions, and orchard management practices. In vitro studies demonstrate that kernel extracts possess substantial antioxidant capacity and exert antiproliferative and cytotoxic effects against various human cancer cell lines, including colon cancer cells, with evidence of apoptosis induction. Extraction methodologies significantly influence bioactive compound recovery and biological activity, with both lipid and phenolic fractions contributing to therapeutic potential. While current evidence highlights promising anti-inflammatory and anticancer properties mediated through modulation of apoptotic pathways, research remains predominantly limited to compositional analyses and in vitro models. Future investigations should elucidate specific molecular mechanisms, identify precise signaling pathway targets, conduct in vivo validation studies, and optimize processing conditions to maximize bioactive retention for potential therapeutic applications in cancer prevention and treatment. Full article

The TCP gene family plays essential roles in plant growth, development, and stress responses, yet their evolutionary dynamics and functional characteristics remain poorly understood in Juglandaceae species. Here, we aimed to systematically identify, classify, and characterize TCP genes across three nut-producing Juglandaceae species—Carya illinoinensis, Annamocarya sinensis, and Juglans regia—to elucidate their evolutionary relationships and potential functions in fruit development. We identified 44, 35, and 36 TCP genes in C. illinoinensis, A. sinensis, and J. regia, respectively, and classified them into three subfamilies (PCF, CIN, and CYC/TB1). Physicochemical property analysis revealed that most proteins were hydrophilic but relatively unstable. Conserved motif and gene structure analyses showed strong similarity among closely related members, while promoter regions were enriched with cis-acting elements associated with development, hormone signaling, and stress responses. Chromosomal mapping demonstrated an uneven distribution of TCP genes, with frequent clustering, and synteny analysis indicated strong conservation and gene duplication within and across species. Transcriptome profiling revealed that approximately half of the TCP genes were expressed in fruit tissues, with CIN subfamily members showing preferential expression. qRT-PCR validation further highlighted AsTCP23, CiTCP14, and JrTCP09 as highly expressed during fruit development, suggesting potential regulatory roles in fruit maturation. These findings provide new insights into the evolutionary patterns and functional divergence of TCP genes in Juglandaceae and establish a valuable foundation for future studies on fruit development and genetic improvement. Collectively, these findings advance our understanding of TCP gene evolution and provide potential molecular targets for improving fruit development and nut quality in Juglandaceae crops. Full article

Sustainable soil management requires striking a balance between productivity and soil health. While agroforestry practices are known to improve soil health and ecosystem functions, the contribution of microbial diversity to maintaining multifunctional soil processes in pecan (Carya illinoinensis) cultivation has yet to be fully elucidated. This study examined microbial diversity, soil functions, and multifunctionality across different pecan intercropping setups. We compared a monoculture pecan plantation with three agroforestry models: pecan–Paeonia suffruticosa–Hemerocallis citrina (CPH), pecan–P. suffruticosa (CPS), and pecan–P. lactiflora (CPL). We employed high-throughput sequencing (16S and ITS) to determine the soil bacterial and fungal communities and analyzed the species diversity, extracellular enzyme activities, and physicochemical properties. Soil multifunctionality (SMF) was evaluated using 20 indicators for nutrient supply, storage, cycling, and environmental regulation. Agroforestry increased soil fungal diversity and improved multifunctionality when compared to monoculture. The CPS and CPH models were the most beneficial, increasing multifunctionality by 0.74 and 0.55 units, respectively. Structural equation modeling revealed two key pathways: bacterial diversity significantly enhanced nutrient cycling and environmental regulation, whereas fungal diversity primarily promoted nutrient cycling. These pathways together delivered clear gains in multifunctionality. Random forest analysis identified key predictors (total nitrogen, total carbon, available potassium, β-1,4-N-acetylglucosaminidase, and alkaline phosphatase), highlighting the joint importance of nutrients and microbial enzymes. Our results demonstrate that selecting species in pecan agroforestry alters microbial communities and activates key functions that support soil health and long-term resilience. Hence, pecan agroforestry maintains SMF through microbial processes, with CPS showing the strongest effect. These results can inform species selection and encourage broader testing for resilient, biodiversity-based farming practices. Full article

Pecan (Carya illinoinensis [Wangenh]. K. Koch) germplasm resources are abundant, yet the characteristics of each cultivar at the seedling stage remain insufficiently understood. This study systematically evaluated the growth parameters, photosynthetic traits, and anatomical structures of one-year-old grafted seedlings from five pecan cultivars: “Pawnee”, “Mandan”, “Nacono”, “Caddo”, and “Creek”. Principal component analysis (PCA) was employed to comprehensively assess 56 indicators. The results indicated that, in terms of vegetative growth, leaf area and biomass of “Nacono” and “Creek” were significantly greater than those of “Pawnee” (p < 0.05). “Mandan” ranked second. Additionally, the seedling quality index of “Creek” was markedly superior to all other cultivars (p < 0.05). Anatomically, “Pawnee” exhibited greater leaf thickness, more highly differentiated palisade tissue, and the development of the main vein. By contrast, “Mandan” displayed larger branch radius, cortex thickness, and pith radius, accompanied by finer vessels and large but sparsely distributed stomata (p < 0.05). Regarding photosynthetic performance, “Mandan” accumulated the highest concentrations of photosynthetic pigments and achieved the greatest photosynthetic efficiency, significantly outperforming the remaining cultivars (p < 0.05). The PCA-based comprehensive evaluation revealed that “Mandan” outperformed the other cultivars in seedling growth, making it the most suitable for promotion, followed by “Creek”, “Nacono”, “Caddo”, and “Pawnee”. This research offers a theoretical foundation for the breeding, promotion, and application of superior pecan cultivars. Full article

Salt stress severely limits the growth and ornamental value of pecan (Carya illinoinensis) in salinized regions, yet the transcriptional mechanisms underlying its stress adaptation remain unclear. In this study, a comprehensive genomic analysis of the GRAS transcription factor family identified 58 CiGRAS genes in pecan. These genes were classified into 11 subfamilies and showed conserved motifs and gene structures, with variation in promoter cis-elements suggesting diverse regulatory functions. Chromosomal distribution and duplication analysis indicated that whole-genome and dispersed duplication events were the main drivers of CiGRAS expansion. Transcriptome data revealed tissue-specific expression and strong responsiveness to salt and other stresses. Under 0.6% NaCl treatment, several CiGRAS genes were significantly upregulated, especially at 48 h. Gene co-expression analysis further highlighted GRAS-enriched modules associated with redox regulation and stress signaling. qRT-PCR validation confirmed time-specific induction of seven CiGRAS genes under salt stress. These findings provide insights into the evolutionary dynamics and stress-related roles of CiGRAS genes and offer candidate regulators for improving pecan salt tolerance in ecological greening and landscape applications. Full article

A simple and fast analytical method was developed and applied to assess the effect of two forms of zinc fertilization on a pecan tree cultivar in Uruguay: fertigation and foliar application with a specially formulated fertilizer. Zinc content was determined in 36 leaf samples from two crop cycles: 2020–2021 and 2021–2022. Fresh samples were dried, ground, and sieved. Analytical determinations were performed by flame atomic absorption spectrometry (FAAS, considered a standard method) and energy dispersive X-ray spectrometry (EDXRF, the proposed method). In the first case, sample preparation was carried out by microwave-assisted digestion using 4.5 mol L⁻¹ HNO₃. In the second case, pellets (Φ 13 mm, 2–3 mm thick) were prepared by direct mechanical pressing. Figures of merit of both methodologies were adequate for the purpose of zinc monitoring. The results obtained from both methodologies were statistically compared and found to be equivalent (95% confidence level). Based on the principles of Green Analytical Chemistry, both procedures were evaluated using the Analytical Greenness Metric Approach (AGREE and AGREEprep) tools. It was concluded that EDXRF was notably greener than FAAS and can be postulated as an alternative to the standard method. The information emerging from the analyses aided decision-making at the agronomic level. Full article

Background: Soil degradation and nutrient depletion critically impact pecan (Carya illinoinensis) production, reducing yield and soil fertility. Colloidal nutrition, a novel approach involving nano-scale nutrient formulations, could offer potential for soil restoration. Aim: This study aimed to assess the impact of colloidal nutrition on key physical, chemical, and biological soil health parameters in pecan tree cultivation. Methods: Soil from two orchards with 30-year-old pecan trees was used where different nutrition treatments were applied: conventional and colloidal. The variables considered included physical, chemical, and biological properties for the assessment of soil health indicators. Results: The colloidal treatment showed low salinity (2020: 2.04; 2021: 0.88 dS/m) and higher levels of humic acids (1.52 g C/100 g soil), available water depth (2020: 305.11, 2021: 350.00 m³/ha), and soil organic matter (2020: 2.10%; 2021: 2.11%). Furthermore, 6 of the 17 phytopathogens that were examined were not detected in the colloidal treatment. Conclusions: This study enhanced our understanding of the improvements that colloidal treatment could potentially provide to the physical, chemical, and biological aspects of soil health in pecan orchards. Full article

Xyloglucan endotransglucosylases/hydrolases (XTHs) are key enzymes involved in cell wall remodeling by modifying xyloglucan–cellulose networks, thereby influencing plant growth, development, and secondary cell wall formation. While the roles of XTHs have been extensively studied in primary and secondary growth, their functions in the formation and thickening of lignified nut shells remain largely unknown. Pecan (Carya illinoinensis), an economically important nut crop, develops a hard, lignified shell that protects the seed during fruit maturation. In this study, we performed a comprehensive genome-wide characterization of the XTH gene family in pecan and identified 38 XTH genes, which were categorized into four distinct phylogenetic groups. Structural analyses of the deduced proteins revealed conserved catalytic residues alongside divergent loop regions, suggesting functional diversification. Expression profiling across various tissues and among pecan cultivars with contrasting shell phenotypes indicated that specific XTH genes may play critical roles in shell structure formation. Moreover, gene regulatory networks in thin- and thick-shelled pecans provided new insights into the molecular mechanisms underlying shell development and thickness regulation. These findings lay a foundation for future genetic improvement strategies targeting nut shell traits in woody perennials. Full article

Carya illinoinensis is a relatively water-tolerant species widely planted in areas with high flood risk. Evaluating its adaptation strategies and tolerance thresholds is crucial for ecological restoration in the context of climate change. In this study, five treatments were applied to 1-year-old C. illinoinensis seedlings in a potting simulation experiment: T1 (field capacity: 75%), T2 (5 cm below the root collar), T3 (up to the root collar), T4 (10 cm above the root collar), and T5 (30 cm above the root collar). The flooding episode lasted for 4 months and was followed by a recovery period of 6 months. The results show that, at the end of flooding, total biomass (TB), stem-mass ratio (SMR), malondialdehyde (MDA), soluble protein (SP), superoxide dismutase (SOD), and catalase (CAT) were significantly increased in all the flooded groups (T2–T5) compared to the control (T1), while the root-to-shoot ratio (RSR), root-to-mass ratio (RMR), leaf-to-mass ratio (LMR), and leaf-mass fraction (LMF) were significantly decreased. Although survival in the high stress group (T5) temporarily decreased to 83.3% (T1–T4 remained 100%), survival in all treatment groups fully recovered (100%) after recovery. Significant decreases (p < 0.001) were observed when comparing post-recovery to end-flooding levels within each flooded group (T2–T5), with reductions ranging: LMR (21.0–30.8%), REL (14.0–26.7%), MDA (16.1–25.3%), SP (42.2–67.3%), SOD (27.6–49.8%), and CAT (47.0–61.3%) across treatments. At this time, T5 showed lower TB and higher MDA, soluble sugars (SS), and SP compared to T1. PCA analysis indicated that the damage ranked as T5 > T4 > T3 > T2 > T1 at the end of flooding, and as T5 > T1 > T4 > T3 > T2 at the end of recovery. Therefore, it could be concluded that 1-year-old C. illinoinensis exhibits high flooding tolerance, with self-recovery thresholds below the T5 treatment, making it suitable for ecological restoration in flood-prone areas. Full article

Drought severely affects the growth and production of pecan (Carya illinoinensis), while genes conferred drought adaptation are yet to be fully elucidated. Here, an in-depth exploration of the two different RNA-seq projects regarding drought stress (designated as P1 and P2) was performed via weighted gene co-expression network analysis. For the two projects, there existed one pair of modules (P1 turquoise module and P2 blue module) that was probably associated with drought resistance, as the paired modules both exhibited an increased expression profile with increasing water shortage stress and were annotated to be involved in oxidative stress response and the signaling pathways of abscisic acid and jasmonic acid. There were 441 and 1258 hub genes in the P1 turquoise module and P2 blue module, respectively, among which, 140 were overlapped and thus were recognized as core drought responsive genes. An additional drought stress experiment was conducted for RT-qPCR validation, and the results showed that the 20 core genes selected for detection were highly responsive to water deficit. Together, our results will be helpful for understanding the molecular mechanism of drought response and improving drought resistance in pecan. Full article

Pecan (Carya illinoinensis) is a world-renowned nut crop that is highly favored by consumers for its high content of healthy nutrients. For a long time, anthracnose has severely threatened the yield and quality of pecan, causing significant economic losses to the global pecan industry. Here, we report the 54.57-Mb gapless chromosome-level assembly of the pathogenic ascomycetes Colletotrichum plurivorum isolate W-6 from pecan plantations in Southeast China. Six of 12 chromosomes contain, at least, telomeric repeats (CCCTAA)n or (TTAGGG)n at one end. A total of 14,343 protein-coding genes were predicted. Pathogenicity- and virulence-related annotations revealed 137 to 4558 genes associated with the TCDB, PHI, Cyt_P450, DFVF, effector, and secretome databases, respectively. A comparative analysis of isolate W-6, together with 51 other Colletotrichum strains, reveled 13 genes unique to the Orchidearum complex to which isolate W-6 belongs, highlighting the major facilitator superfamily transporters. The detailed analyses of MFS transporters associated with secondary metabolite gene clusters in isolate W-6 led to the identification and protein structure analyses of two key virulence factor candidates in DHA1 subclass, prlG and azaK, which were reported as efflux transporters of antibiotics in other pathogenic fungi. The assembly and further functional investigation of two pathogenic genes identified here potentially provide important resources for better understanding the biology and lifestyle of Colletotrichum and pave the way for designing more efficient strategies to control anthracnose in pecan plantations. Full article