Sheng Zhu

NAC (NAM, ATAF1/2 and CUC2) transcription factors constitute one of the largest plant-specific transcription factor families and play pivotal roles in plant growth, development, and responses to environmental stresses. Systematic characterization of NAC genes is essential for understanding regulatory networks underlying key agronomic and adaptive traits. As a conservation-priority woody species with distinctive biological and horticultural value, Sinojackia xylocarpa Hu lacks comprehensive knowledge of its NAC repertoire, and elucidating its NAC family will facilitate functional studies related to development and environmental adaptation. Based on whole-genome data of S. xylocarpa, we conducted a systematic survey and characterization of the NAC transcription factor family. In total, 115 SxyNAC genes encoding the conserved NAC domain were identified, and their loci were unevenly distributed across 12 chromosomes. Analyses of gene-duplication modes and collinearity indicated that whole-genome/segmental duplication events were the major driving force for the expansion of this family. Phylogenetic relationships, gene structures, and conserved motifs classified the SxyNAC members into 15 subfamilies, revealing a highly conserved N-terminal NAC domain and a markedly diversified C-terminal regulatory region with pronounced member- and lineage-specific differences. Promoter cis-element prediction showed extensive enrichment of light-responsive, phytohormone-responsive, and stress-related elements, suggesting that SxyNAC genes may participate in coordinated regulation of multiple environmental cues and endogenous hormone pathways. Transcriptome data from six fruit developmental stages, together with qRT-PCR validation of ten representative genes, demonstrated diverse temporal and tissue-specific expression patterns during fruit development and close associations with fruit growth regulation. Overall, our findings establish a framework for exploring the evolutionary trajectories and functional diversification of NAC genes in S. xylocarpa, and they offer a valuable resource for NAC-family research and conservation-focused functional genomics in other rare or threatened plant species.

The spring transition in bermudagrass (Cynodon dactylon) overseeded with perennial ryegrass (Lolium perenne) remains a major challenge in turf management due to persistent competition from the cool-season species. Conventional practices such as core cultivation can damage bermudagrass stands and delay recovery. This study evaluated a novel, non-damaging approach using a yeast-based fertilizer to enhance bermudagrass regrowth during the transition period. The fertilizer consisted of Saccharomyces cerevisiae and glucose applied as a soil drench. A greenhouse experiment was conducted over two years (2023–2024) using “Yangjiang” bermudagrass overseeded with “Wintergame” perennial ryegrass. Five treatments were compared: control (0 g·m⁻² yeast + 0 g·m⁻² glucose), yeast alone (200 g·m⁻²), and yeast combined with glucose at 100, 200, or 400 g·m⁻². Growth parameters were assessed at 7, 14, and 28 days after treatment. The application of 200 g·m⁻² yeast + 200 g·m⁻² glucose yielded the most significant improvements. At 14 days, bermudagrass shoot density and turf cover significantly (p < 0.05) increased by 45.81% and 129.51%, respectively, compared to the control. By 28 days, aboveground and belowground biomass significantly (p < 0.05) increased by 308.14% and 51.35%, respectively. Root system architecture was also significantly (p < 0.05) enhanced, with total root length, surface area, and volume rising by 62.05%, 40.59%, and 63.51%. These results demonstrate that yeast fertilizer strongly promotes bermudagrass shoot and root growth during spring transition, likely by generating CO₂ to improve soil porosity without physical turf injury. This method provides a practical and complementary strategy for managing overseeded turfgrass systems.

Plants growing in natural environments are constantly exposed to various biotic and abiotic stresses, among which drought is a major abiotic factor that se

Sinojackia Hu represents the first woody genus described by Chinese botanists, with all species classified as endangered ornamental plants endemic to China. Their characteristic spindle-shaped fruits confer high ornamental value to the plants, making them favored in gardens and parks. Nevertheless, the fruits likely pose a germination obstacle, contributing to the endangered status of this lineage. Here we report the chromosome-scale genome of S. xylocarpa, and explore the mechanisms underlying its endangered status, as well as its population dynamics throughout evolution. Population genomic analysis has indicated that S. xylocarpa experienced a bottleneck effect following the recent glacial period, leading to a continuous population reduction. Examination of the pericarp composition across six stages of fruit development revealed a consistent increase in the accumulation of lignin and fiber content, responsible for the sturdiness of mature fruits’ pericarps. At molecular level, enhanced gene expression in the biosynthesis of lignin, cellulose and hemicellulose was detected in pericarps. Therefore, we conclude that the highly lignified and fibrotic pericarps of S. xylocarpa, which inhibit its seed germination, should be its threatening mechanism, thus proposing corresponding strategies for improved conservation and restoration. This study serves as a seminal contribution to conservation biology, offering valuable insights for the study of other endangered ornamental plants.

Fungal effectors play critical roles in manipulating plant immune responses and promoting colonization. Sphaerulina musiva is a heterothallic ascomycete fungus that causes Septoria leaf spot and stem canker disease in poplar (Populus spp.) plantations. This disease can result in premature defoliation, branch and stem breakage, increased mortality, and plantation failure. However, little is known about the interaction between S. musiva and poplar. Previous work predicted 142 candidate secreted effector proteins in S. musiva (SmCSEPs), 19 of which were selected for further functional characterization in this study. SmCSEP3 induced plant cell death in Nicotiana benthamiana, while 8 out of 19 tested SmCSEPs suppressed cell death. The signal peptides of these eight SmCSEPs exhibited secretory activity in a yeast signal sequence trap assay. Confocal microscopy revealed that four of these eight SmCSEPs target both the cytoplasm and the nucleus, whereas four predominantly localize to discrete punctate structures. Pathogen challenge assays in N. benthamiana demonstrated that the transient expression of six SmCSEPs promoted Fusarium proliferatum infection. The expression of these six SmCSEP genes were induced during infection. SmCSEP2, SmCSEP13, and SmCSEP25 suppressed chitin-triggered reactive oxygen species burst and callose deposition in N. benthamiana. The candidate secreted effector proteins of S. musiva target multiple compartments in the plant cell and modulate different pattern-triggered immunity pathways.The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2023.

As an important timber genus with high economic and ecological values, Populus is a model for dissecting the genetic architecture of growth traits in perennial forest trees. However, the genetic mechanisms of longitudinal growth traits in poplar remain incompletely understood. In this study, we conducted longitudinal genetic analysis of height and diameter at breast height (DBH) in eleven-year poplar clones using ultra-deep sequencing datasets. We compared four S-shaped growth models, including asymptotic, Gompertz, logistic, and Richard, on eleven-year height and DBH records in terms of five metrics. We constructed the best-fitting growth model (Richard) and determined poplar ontogenetic stages by virtue of growth curve fitting and likelihood ratio testing. This study provides some scientific clues for temporal variation of longitudinal growth traits in Populus species.

Image-based morphometric technology is broadly applicable to generate large-scale phenomic datasets in ecological, genetic and morphological studies. However, little is known about the performance of image-based measuring methods on plant morphological characters. In this study, we presented an automatic image-based workflow to obtain the accurate estimations for basic leaf characteristics (e.g., ratio of length/width, length, width, and area) from a hundred Populus simonii pictures, which were captured on Colony counter Scan1200. The image-based workflow was implemented with Python and OpenCV, and subdivided into three parts, including image pre-processing, image segmentation and object contour detection. Six image segmentation methods, including Chan-Vese, Iterative threshold, K-Mean, Mean, OSTU, and Watershed, differed in the running time, noise sensitivity and accuracy. The image-based estimates and measured values for leaf morphological traits had a strong correlation coefficient (r² > 0.9736), and their residual errors followed a Gaussian distribution with a mean of almost zero. Iterative threshold, K-Mean, OSTU, and Watershed overperformed the other two methods in terms of efficiency and accuracy. This study highlights the high-quality and high-throughput of autonomous image-based phenotyping and offers a guiding clue for the practical use of suitable image-based technologies in biological and ecological research.

The R2R3-MYB genes in plants play an essential role in the drought-responsive signaling pathway. Plenty of R2R3-MYB S21 and S22 subgroup genes in Arabidopsis have been implicated in dehydration conditions, yet few have been covered in terms of the role of the S21 and S22 subgroup genes in poplar under drought. PdMYB2R089 and PdMYB2R151 genes, respectively belonging to the S21 and S22 subgroups of NL895 (Populus deltoides × P. euramericana cv. ‘Nanlin895′), were selected based on the previous expression analysis of poplar R2R3-MYB genes that are responsive to dehydration. The regulatory functions of two target genes in plant responses to drought stress were studied and speculated through the genetic transformation of Arabidopsis thaliana. PdMYB2R089 and PdMYB2R151 could promote the closure of stomata in leaves, lessen the production of malondialdehyde (MDA), enhance the activity of the peroxidase (POD) enzyme, and shorten the life cycle of transgenic plants, in part owing to their similar conserved domains. Moreover, PdMYB2R089 could strengthen root length and lateral root growth. These results suggest that PdMYB2R089 and PdMYB2R151 genes might have the potential to improve drought adaptability in plants. In addition, PdMYB2R151 could significantly improve the seed germination rate of transgenic Arabidopsis, but PdMYB2R089 could not. This finding provides a clue for the subsequent functional dissection of S21 and S22 subgroup genes in poplar that is responsive to drought.