To assess changes of metabolite content and regulation mechanism of the phenolic acid biosynthesis pathway at different developmental stages of leaves, this study performed a combined metabolome and transcriptome analysis of Cyclocarya paliurus leaves at different developmental stages. Metabolite and transcript profiling were conducted by ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometer and high-throughput RNA sequencing, respectively. Transcriptome identification showed that 58 genes were involved in the biosynthesis of phenolic acid. Among them, 10 differentially expressed genes were detected between every two developmental stages. Identification and quantification of metabolites indicated that 14 metabolites were located in the phenolic acid biosynthetic pathway. Among them, eight differentially accumulated metabolites were detected between every two developmental stages. Association analysis between metabolome and transcriptome showed that six differentially expressed structural genes were significantly positively correlated with metabolite accumulation and showed similar expression trends. A total of 128 transcription factors were identified that may be involved in the regulation of phenolic acid biosynthesis; these include 12 MYBs and 10 basic helix–loop–helix (bHLH) transcription factors. A regulatory network of the phenolic acid biosynthesis was established to visualize differentially expressed candidate genes that are involved in the accumulation of metabolites with significant differences. The results of this study contribute to the further understanding of phenolic acid biosynthesis during the development of leaves of C. paliurus.

Background: Microtubule organization is essential for bipolar spindle assembly and chromosome segregation, which contribute to genome stability. Kinesin-5 Eg5 is known to be a crucial regulator in centrosome separation and spindle assembly in mammalian somatic cells, however, the functions and mechanisms of Eg5 in male meiotic cell division remain largely unknown.Results: In this study, we have found that Eg5 proteins are expressed in mouse spermatogonia, spermatocytes and spermatids. After Eg5 inhibition by specific inhibitors Monastrol, STLC and Dimethylenastron, the meiotic spindles of dividing spermatocytes show spindle collapse and the defects in bipolar spindle formation. We demonstrate that Eg5 regulates spindle bipolarity and the maintenance of meiotic spindles in meiosis. Eg5 inhibition leads to monopolar spindles, spindle abnormalities and chromosome misalignment in cultured GC-2 spd cells. Furthermore, Eg5 inhibition results in the decrease of the spermatids and the abnormalities in mature sperms.Conclusions: Our results have revealed an important role of kinesin-5 Eg5 in male meiosis and the maintenance of male fertility. We demonstrate that Eg5 is crucial for bipolar spindle assembly and chromosome alignment in dividing spermatocytes. Our data provide insights into the functions of Eg5 in meiotic spindle assembly of dividing spermatocytes.

Understanding the light adaptation of plants is critical for conservation. Platycrater arguta, an endangered deciduous shrub endemic to East Asia, possesses high ornamental and phylogeographic value. However, the weak environmental adaptability of P. arguta species has limited its general growth and conservation. To obtain a deeper understanding of the P. arguta growth conditions, we examined the leaf morphology and physiology via anatomical and chloroplast ultrastructural analyses following exposure to different natural light intensities (full light, 40%, and 10%). The findings indicated that P. arguta seedings in the 10% light intensity had significantly improved leaf morphological characteristics and specific leaf area compared to those exposed to other intensities. The net photosynthetic rate, chlorophyll (Chl) content, photosynthetic nitrogen use efficiency (PNUE), and photosynthetic phosphorus use efficiency (PPUE) exhibited marked increases at a 10% light intensity compared to both 40% light and full light intensities, whereas the light compensation point and dark respiration levels reached their lowest values under the 10% light condition. With reduced light, leaf thickness, palisade tissue, spongy tissue, and stomatal density significantly decreased, whereas the stomatal length, stomatal width, and stomatal aperture were significantly elevated. When exposed to 10% light intensity, the ultrastructure of chloroplasts was well developed, chloroplasts and starch grain size, the number of grana, and thylakoids all increased significantly, while the number of plastoglobules was significantly reduced. Relative distance phenotypic plasticity index analysis exhibited that P. arguta adapts to varying light environments predominantly by adjusting PPUE, Chl b, PNUE, chloroplast area, and the activity of PSII reaction centers. We proposed that P. arguta efficiently utilizes low light to reconfigure its energy metabolism by regulating its leaf structure, photosynthetic capacity, nutrient use efficiency, and chloroplast development.

The leaf photosynthetic capacity, leaf N partitioning, non-structural carbohydrate content, C, N, and P contents of endangered U. elongata seedlings exposed to different light intensities were compared in this study. The most favorable light condition for the survival and growth of U. elongata seedlings in the present study was 100% full sunlight, as this induced higher P_n, PNUE, P_C, P_R, P_B, and NSC content relative to shade-treated seedlings. PNUE, P_R, P_C, and P_B in U. elongata seedling leaves decreased under 40% and 10% full sunlight, while P_L increased, indicating that shade increased the light capture efficiency of photosystem (PS) II but decreased electron transfer from PSII to PSI. Furthermore, leaf N content increased with shade intensity, revealing an adaptive strategy for poor light environments. Additionally, the smallest leaf biomass, P_n, WUE, and CE values and C:N and C:P ratios in stems and leaves were observed under 10% full sunlight. These results indicate that seedlings growing under 40% full sunlight will benefit U. elongata conservation.

Arbuscular mycorrhizal fungi (AMF) are considered crucial for the survival of many endangered plant species. However, the dynamics of AMF communities in the roots and rhizosphere soil of Heptacodium miconioides, particularly along elevation gradients, remain underexplored. This study investigates AMF colonization, spore density, and community structure in the root and rhizosphere soil of H. miconioides across an elevation range from 306 to 1028 m a.s.l., employing high-throughput sequencing. Our results show that AMF colonization and spore density in H. miconioides increased with elevation. Glomus was the dominant genus in both root and rhizosphere samples. Elevation significantly influenced the AMF community structure and diversity in the root, with alpha diversity decreasing linearly with elevation. In contrast, no significant elevation-related changes were observed in the rhizosphere soil alpha diversity. The difference in AMF beta diversity between the root and rhizosphere soil was lowest at the highest elevation. Compared to the rhizosphere soil, the degree and degree centralization of AMF community co-occurrence networks in the root showed a significant increase at higher elevations. Variations in soil properties, particularly soil pH, available phosphorus, and total nitrogen levels strongly influenced AMF communities in rhizosphere soil, while nitrate nitrogen, available potassium, and acid phosphatase were correlated with AMF communities in the root. These findings highlight the impact of elevation on AMF communities in both root and rhizosphere soil, providing valuable insights for the habitat restoration and conservation efforts for this species.

Yueling Li, Sebastian Martschat, Simone Paolo Ponzetto. The 22nd Workshop on Biomedical Natural Language Processing and BioNLP Shared Tasks. 2023.