Hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT) is considered to be an essential enzyme for regulating the biosynthesis and composition of lignin. To investigate the properties and function of ZjHCT4, the ZjHCT4 gene was cloned from Zoysia japonica with a completed coding sequence of 1284-bp in length, encoding 428 amino acids. The ZjHCT4 gene promoter has several methyl jasmonate (MeJA) response elements. According to analysis of expression patterns, it was up-regulated by MeJA, GA₃ (Gibberellin), and SA (Salicylic acid), and down-regulated by ABA (Abscisic acid). Ectopic ZjHCT4 expression in creeping bentgrass causes excessive plant elongation. In addition, the content of G-lingnin and H-lingnin fell in transgenic plants, whereas the level of S-lingnin increased, resulting in a considerable rise in the S/G unit ratio. Analysis of the expression levels of lignin-related genes revealed that the ectopic expression of ZjHCT4 altered the expression levels of a number of genes involved in the lignin synthesis pathway. Simultaneously, MeJA, SA, GA₃, IAA, BR (Brassinosteroid), and other hormones were dramatically enhanced in transgenic plants relative to control plants, whereas ABA concentration was significantly decreased. Expression of ZjHCT4 impacted lignin composition and plant growth via altering the phenylpropionic acid metabolic pathway and hormone response, as revealed by transcriptome analysis. HCTs may influence plant lignin composition and plant development by altering hormone content. These findings contributed to a deeper comprehension of the lignin synthesis pathway and set the stage for further investigation and application of the HCTs gene.

In recent years, highway construction in the Qinghai-Tibet Plateau (QTP) has developed rapidly. When the highway passes through grassland, the soil, vegetation, and ecological environment along the line are disturbed. However, the impact on soil bacteria is still unclear. Soil bacteria play an important role in the ecological environment. The Qinghai-Tibet Highway (QTH) was selected as the research object to explore the changes in bacterial community structure, vegetation, soil, and other indicators. The results showed that the highway-related activities increased the degradation of vegetation along the road, significantly changed the physical and chemical properties of soil, and caused heavy metal pollution. These environmental factors affected the diversity and community structure of soil bacteria. This kind of disturbance shows a trend of gradually increasing from near to far from the highway. Gemmatimonas, Terrimonas, Nitrospira and Bacillus are more tolerant to environmental changes along the highway, while Barnesiella, and Blastococcus are more sensitive. The content of nitrate decreased and the content of ammonium nitrogen increased in the disturbed area, increasing the abundance of nitrifying bacteria. Therefore, the main factor of the disturbance of the QTH on the grassland is the decline of soil nutrient content, and the supplement of soil nutrients such as carbon and nitrogen should be taken into account in the process of ecological restoration of grassland along the line.

The NYC-like (NOL) enzyme is considered as an essential enzyme for chlorophyll b degradation, which catalyzes the formation of 7-hydroxymethyl chlorophyll a from chlorophyll b. The ZjNOL gene was cloned from Zoysia japonica with a completed coding sequence of 981-bp in length, encoding 326 amino acids. ZjNOL was localized on the stroma side of the thylakoid membrane, and co-localized with ZjNYC in the chloroplasts. Multiple photoregulatory elements and hormone regulatory elements were identified in the promoter region of the ZjNOL gene, and the expression level of the ZjNOL gene was dramatically up-regulated in senescence leaves, which were regulated by a variety of plant hormones. ZjNOL’s ectopic expression in creeping bentgrass produced yellow leaves, thicker cortex, and smaller vascular column cells. Additionally, transgenic plants exhibited morphological alterations in their chloroplast structure, and the number of grana and thylakoids per grana stack reduced dramatically. Transgenic plants also had a lower photosynthetic rate and Fm/Fv than the control. The transgenic plants displayed a decreased chlorophyll content and a greater rate of ion leakage. The properties and activities of ZjNOL will serve as a foundation for future research into gene functions and regulatory processes.

The TGACG motif-binding factor1 (TGA1) transcription factor, a significant protein in the bZIP transcription factor family, exhibits a myriad of functions, contributes to numerous biological events, and holds substantial application potential. In this study, our analysis revealed a diverse range of photoregulatory and hormone regulatory elements within the MtTGA1 promoter region. The expression profile of MtTGA1 indicated its highest expression in the root, with its regulation influenced by SA, ABA, BR, and GA. Under salt stress conditions, transgenic plants demonstrated significantly longer root lengths and heightened activities of antioxidant enzymes such as ascorbic acid catalase (APX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) in their roots and leaves compared to control plants. Simultaneously, the levels of endogenous hormones ABA and BR escalated in transgenic plants, with a marked change in the morphology of their leaf cells. Transcriptome analysis identified a total of 193 differentially expressed genes, implicating a wide array of biological processes. Furthermore, we found that MtTGA1 is able to interact with Medicago truncatula SPX domain containing protein 1 (SPX1). In conclusion, the MtTGA1 transcription factor plays a crucial role in enhancing salt tolerance, which provides new insights for improving plant survival under salt stress conditions.

Highlight: Integration of ATAC-seq and RNA-seq identifies novel candidate genes associated with drought tolerance in Zoysia japonica Steud. The warm-season turfgrass Zoysia japonica is renowned for its drought resistance and serves as an exceptional domestic turfgrass in China. In order to unlock the potential of this native grass, identify drought-resistant genes, enhance the genetic transformation system, and maximize its utilization benefits, we conducted physiological characterization, multi-omics analysis, and RT-qPCR experimental verification in Zoysia japonica. This study suggested that 63 high-confidence genes related to drought stress and 6 motifs regulating drought responses were identified using a combined omics approach and RT-qPCR validation. The study discovered a positive correlation between ATAC-Seq peak intensity and gene expression levels. The expression of high-confidence genes was linked to Zoysia japonica resistance evaluation and phenotypic traits, implying that these genes are involved in responding to external drought stress. This study combined ATAC-seq and RNA-seq technologies for the first time to identify drought-related genes in Zoysia japonica , elucidating the grass’s adaptation to environmental stress and the regulatory mechanisms underlying stress responses, and laying the groundwork for Zoysia japonica improvement and breeding.