Journal of Plant Research最新文献

Bryophytes, pteridophytes, and some gymnosperm species produce motile ciliated spermatozoids that navigate to the egg by regulating ciliary motility in response to a concentration gradient of attractants released from the egg and/or the surrounding cells. However, the structural components of spermatozoid cilia in land plants remain largely unknown. In this study, we investigated MpCAFA (combined calcyphosine [CAPS] with flagellar-associated protein 115 [FAP115]; Mp1g04120) in the liverwort Marchantia polymorpha. The N-terminal and near C-terminal regions of MpCAFA showed similarity to CAPS, a mammalian EF-hand protein, and FAP115, a ciliary protein of the green alga Chlamydomonas reinhardtii, respectively. MpCAFA was expressed specifically in antheridia and its orthologs were found in some algae, bryophytes, pteridophytes, and some gymnosperm species, but not in most seed plants. Spermatozoids from mutants lacking functional MpCAFA exhibited a significant decrease in swimming speed. Notably, these mutants showed no obvious morphological defects, including a 9 + 2 axoneme arrangement, and retained chemotactic capability and fertility, forming normal spores. This suggests that MpCAFA is required for spermatozoid motility, but not for sperm chemotaxis or subsequent reproductive processes. The introduction of MpCAFA_pro:MpCAFA-mCitrine fully complemented the mutant phenotype and revealed that MpCAFA-mCitrine was localized along the lengths of the two spermatozoid cilia. Both the CAPS-like and FAP115-like domains were essential for MpCAFA function and subcellular localization in spermatozoid, whereas the C-terminal proline-rich region was required only for function. These findings indicate that MpCAFA is a major ciliary protein in land plants and can serve as a marker for visualizing spermatozoid ciliary movements.

Forest fragmentation induced by urbanization usually has a negative effect on gene flow by limiting animal-mediated seed dispersal. Since the effect of forest fragmentation on animal-induced seed dispersal is related to seed size, it is likely that the impact of such fragmentation on genetic structure varies among the species with different seed sizes. To test this prediction, we investigated the genetic diversity, structure and kinship structure of seedlings and adult trees in two different seed-sized oaks, Quercus variabilis and Quercus chenii, which are undergoing seed dispersal limitation in urban areas, e.g. Wuhan city, a rapidly urbanizing megacity in central China. Compared to the large-seeded oak Q. variabilis, more full-sibling and maternal-offspring pairs of the small-seeded oak Q. chenii were detected among and within forest patches, indicating small-seeded species was enduring less restricted seed-mediated gene flow than large-seeded species in urban areas. For both oaks, genetic differentiation of seedlings mainly occurred within populations instead of among populations, and more half-siblings than full-sibling pairs and more paternal-offspring than maternal-offspring pairs were observed. In addition, genetic diversity within forests was positively associated with population size. The results indicate frequent gene flow of oaks, mainly from wind pollination, exists among urban forest patches and then offsets the reductions of gene flow from seed dispersal. Our results suggest that wind-pollinated and animal-dispersal small-seeded species, might suffer from less limitation of gene flow in fragmented urban forests, thus they can be candidates for urban greening and planting. In addition, enhancing habitat connectivity and maintaining large populations are also essential to promote gene flow and preserve genetic diversity.

De novo organogenesis is a key process in plant development and regeneration, enabling plants to adapt and survive under suboptimal conditions. Studying the molecular mechanisms of cellular reprogramming that drives new organ formation has been challenging since only a subset of cells among heterogeneous cell populations change the cell fate. Recent advancements in single-cell technologies, however, have begun to provide unprecedented insights into the cell identities and their developmental trajectories, offering a deeper understanding of cell fate transitions during this process. In this review we highlight how single-cell approaches help uncover the regulatory networks that govern cell fate reprogramming and propose future directions for improving temporal and spatial resolution to further advance this emerging field.

Invasive alien plants can act as "drivers", actively modifying plant community succession, or as "passengers", passively persisting without significantly affecting vegetation dynamics. Canada goldenrod (Solidago canadensis) is considered a 'passenger' species, transiently dominating old-field communities in Europe, while research in Asia indicates that different geo-cytotypes of S. canadensis influence succession in a cytogeography-dependent manner, with introduced polyploids acting as drivers. However, whether these effects are temporary or long-lasting remains unclear, necessitating long-term observation. We conducted a 10-year common garden experiment to investigate the impact of different geo-cytotypes of S. canadensis on succession in old-field plant communities. Both diploid and native polyploid populations subjected to regular mowing, gradually disappeared, while herbaceous plant communities transitioned to woody communities by the fourth year. In contrast, introduced polyploid S. canadensis co-dominated alongside woody plants until the eighth year. By the tenth year, all communities, including those initially dominated by introduced polyploids, were primarily composed of woody species. While the geo-cytotype influenced the rate of succession, it did not alter its course. These findings suggest that, regardless of geo-cytotype, S. canadensis ultimately functions as a passenger in the long-term succession of invaded plant communities.

Alexa grandiflora Ducke is a papilionoid legume tree native to the Brazilian Amazon Forest. It belongs to the early-diverging Angylocalyx clade within the subfamily Papilionoideae, which is characterized by keel flowers, with some genera having flowers other than typical papilionaceous ones. This study describes the floral organography, organogenesis, and secretory structures of A. grandiflora and compares its floral morphology with that of three species from different genera within the Angylocalyx clade to deepen the understanding of the clade's floral structure and, by extension, the broader Papilionoideae subfamily. To conduct the study, floral buds and flowers from A. grandiflora were collected and processed for surface and anatomical studies, and flowers from herbarium specimens of Castanospermum australe, Xanthocercis madagascariensis and Angylocalyx oligophyllus to elucidate the clade's floral evolution and its implications for Papilionoideae diversity. Floral buds and flowers of A. grandiflora were analyzed using surface and anatomical techniques, while herbarium specimens of the comparative taxa were examined via scanning electron microscopy. In A. grandiflora, the apical meristem of the racemose inflorescence primary axis produces first-order bracts acropetally in a helical order. Sepal initiation is unidirectional, petal initiation is simultaneous, with the adaxial petal growing faster than the others. Antesepalous stamens appear simultaneously and concurrently with the carpel, while antepetalous stamens emerge simultaneously. Floral secretion of nectar, terpenes, and oleoresin supports phyllostomid bat pollination in Alexa species, consistent with the previously proposed association between intense nectar and terpene production and chiropterophily in the genus. Comparative analysis reveals that the Angylocalyx clade shares key floral traits, including a gamosepalous calyx, an enlarged adaxial petal, and similarly shaped lateral and abaxial petals. However, variations are observed in the type of inflorescence and in the level of insertion of the filament in the anther, highlighting the floral diversity within the clade.

Flower opening time (FOT) is a key trait for successful reproduction and reproductive isolation. In crop science, FOT is critical for stress avoidance and efficient breeding practices. This study developed a system for the automatic detection of rice flower openings and FOT estimation by integrating a low-cost time-lapse camera with machine learning technology. This approach enabled high-resolution monitoring of flowering dynamics in two cultivars: the japonica cultivar Taichung 65 (T65) and the indica cultivar IR24. The system accurately identified regions containing open flowers, and the estimated FOTs varied within a 3-h range, with a root mean square error of approximately 30 min compared to manual detection. A significant difference in estimated FOTs between IR24 and T65 demonstrated the system's potential for genetic screening applications. FOT of both cultivars exhibited a significant negative correlation with daily mean temperature. Notably, a temperature-sensitive period was identified in the morning, suggesting that temperature influences not only flower opening but also preceding physiological processes such as panicle and spikelet development. This study presents a novel approach to investigating FOT dynamics in rice and provides insights into the interaction between environmental factors and internal regulatory mechanisms governing this critical reproductive trait.

The lacquer tree Toxicodendron trichocarpum (Miq) Kuntze (Anacardiaceae: Rhoideae), which is known for its abundance of urushiol, produces a high-quality raw lacquer. There have been five complete chloroplast genomes reported in the genus Toxicodendron, while, only two T. trichocarpum genes were sequenced and used for phylogenetic and biogeographic analysis. In this study, we sequenced the T. trichocarpum whole genome on the Illumina HiSeq 4000 platform and investigated its complete chloroplast genome characteristics. Our results showed that the length of the chloroplast genome of T. trichocarpum was 159,959 bp with a GC content of 37.9%. The genome was found to comprise a large single-copy region (LSC) spanning 87,964 bp, a small single-copy region (SSC) of 18,979 bp, and two inverted repeat regions (IRa/IRb) of equal length, each measuring 26,508 bp. A total of 134 genes were annotated, consisting of 89 protein-coding genes, 37 tRNA genes and eight rRNA genes. Altogether, 84 chloroplast simple sequence repeats (SSRs) were identified, predominantly composed of single nucleotides (A/T), with a clear preference for A/T. By comparing the chloroplast genomes of the genus Toxicodendron, six relatively highly variable regions were identified for future molecular marker development. Phylogenetic analyses conducted within the tribe Rhoideae strongly supported the monophyly of the genus Toxicodendron. The species T. trichocarpum was sister to T. diversilobum, with a high level of support at 99%, forming a clade with T. griffithii and T. vernicifluum. Divergence time estimation suggested that Toxicodendron was originated at 42.47 mya (95% HPD: 41.99-42.99 mya) and T. trichocarpum occurred concomitantly with the sister species T. diversilobum at approximately 16.33 mya. We first reported the complete chloroplast genome of T. trichocarpum and comparative analysis of the Toxicodendron species, which will provide valuable genomic information for accurate classification and evolutionary process of this important taxa in the future.