Poa pratensis is one of the world’s most widely planted cold-season turfgrasses, with good quality but poor drought resistance. When plants suffer from stress, the metabolism of soluble sugar takes place, which is a dynamic process involving both degradation and synthesis. A detailed and in-depth study of the sugar metabolism process in plants’ response to stress will help us to understand the internal mechanism of plant adaptation to stress. In this study, the ‘10-202’ ecotype with drought resistance and the ‘Blue moon’ ecotype with drought sensitivity were used to explore the sugar metabolism process in response to drought stress. The results showed that drought stress induced sucrose accumulation in the leaves and roots, promoted increases in SPS, S-AI, and PpN/A-Inv activities, as well as gene expression in the leaves, and changed the content and distribution of fructose, glucose, sucrose, maltose, and trehalose in vivo. Compared with ‘Blue moon’, ‘10-202’ had higher trehalose content in leaves under normal conditions, and its roots could accumulate more fructose and glucose to maintain the balance of osmotic potential and redox under drought stress. Meanwhile, PpSWEET1b, -12, and -15 in the leaves and roots of the two ecotypes were significantly induced by drought stress. The improvements in sucrose accumulation and decomposition efficiency in leaves under drought stress is conducive to enhancing drought resistance in plants. PpSWEET1b plays a vital role in regulating the sugar transport process of drought tolerance in turfgrass.

Polycyclic aromatic hydrocarbons (PAHs) cause serious stress to biological health and the soil environment as persistent pollutants. Despite the wide use of biochar in promoting soil improvement, the mechanism of biochar removing soil PAHs through rhizosphere effect in the process of phytoremediation remain uncertain. In this study, the regulation of soil niche and microbial degradation strategies under plants and biochar were explored by analyzing the effects of plants and biochar on microbial community composition, soil metabolism and enzyme activity in the process of PAH degradation. The combination of plants and biochar significantly increased the removal of phenanthrene (6.10%), pyrene (11.50%), benzo[a]pyrene (106.02%) and PAHs (27.10%) when compared with natural attenuation, and significantly increased the removal of benzo[a]pyrene (34.51%) and PAHs (5.96%) when compared with phytoremediation. Compared with phytoremediation, the combination of plants and biochar significantly increased soil nutrient availability, enhanced soil enzyme activity (urease and catalase), improved soil microbial carbon metabolism and amino acid metabolism, thereby benefiting microbial resistance to PAH stress. In addition, the activity of soil enzymes (dehydrogenase, polyphenol oxidase and laccase) and the expression of genes involved in the degradation and microorganisms (streptomyces, curvularia, mortierella and acremonium) were up-regulated through the combined action of plants and biochar. In view of the aforementioned results, the combined application of plants and biochar can enhance the degradation of PAHs and alleviate the stress of PAH on soil microorganisms.

Introduction: Lodging has become an important factor limiting oats production.Methods: To understand the relationship between oat lodging and stem growth, we selected three oat cultivars with different lodging resistance traits and conducted a detailed analysis of their stem physicochemical properties, and transcriptome sequencing on them at different growth stages were performed.Results: Important plant characteristics like: length of the second stem internode, stem wall thickness, breaking force, mechanical strength, soluble sugar, starch, lignin, and silicon content were closely related to oat lodging performance. With the growth of the second stem internode at the base of oats, the number of coexpressed differentially expressed genes (DEGs) increased. And DEGs were specifically enriched in starch and sucrose metabolism, phenylpropanoidbiosynthesis, MAPK signaling pathway-plant and carbon metabolism. There were many TF family types among the different comparison groups, and p450, Myb_DNA-binding, WRKY, and AP2 families accounted for the most. Additionally, there was a specific high expression of genes related to the synthesis of cellulose(CesA9, CesA7, and CesA4) and lignin (CCR1, 4CL8, and 4CL3) in lodgingresistant cultivar and middle lodging-resistant cultivar. WGCNA analysis identified genes closely related to lodging resistance, namely MBF1c, SKP1, and CAND1, which were specifically up-regulated on the 35th day of growth in the second stem internode of the highly resistant ‘LENA’. These genes can all serve as positive regulatory factors for oat lodging.Discussion: Ultimately, our work analyzed the transcriptional network regulatory relationships, laying the foundation for elucidating the physiological and genetic mechanisms of oat lodging resistance, and providing excellent genetic resources for oat and other crop breeding.

Buchloe dactyloides is one of the typical ecological grass species, characterized by its strong salt tolerance. Hexokinase (HXK) plays a crucial role in plant growth, development, and resistance to abiotic stresses. To understand the function of HXKs in the salt tolerance of B. dactyloides, this study identified and analyzed the HXK gene family members using the whole-genome data of B. dactyloides. Additionally, transcriptomic methods were employed to investigate the expression levels and stress response patterns of the HXK family genes under salt stress. The results showed that 25 HXK genes were identified in the B. dactyloides HXK gene family, which were classified into three subfamilies based on the phylogenetic tree. Members within the same subfamily exhibited similar gene structures and conserved motifs. The promoter regions of BdHXKs contained numerous cis-regulatory elements associated with plant hormone responses, plant growth and development, and resistance to abiotic stresses. Quantitative real-time PCR analysis provided preliminary evidence that the BdHXK5, BdHXK7, and BdHXK23 genes might play important roles in the salt tolerance regulation of B. dactyloides. These findings offer a theoretical foundation for further elucidating the functions and molecular regulatory mechanisms of BdHXKs under salt stress. This study has provided a theoretical basis for the breeding of new varieties of ecological restoration grasses with stronger salt tolerance and better growth and development. This is of great significance for the improvement and ecological restoration of saline–alkali land.

The tall wheatgrass Thinopyrum ponticum has excellent saline–alkali tolerance and great potential for restoring saline–alkali land to enhance productivity. This study used the Thinopyrum ponticum cv. “Orbit” variety, which is widely planted in saline–alkali pastures, as the material and artificially simulated salt stress using 150 mM NaCl and 150 mM Na₂SO₄, respectively. The growth and physiological indexes of the leaves and roots of seedlings were measured after various treatment durations, and the transcriptomes of untreated and Na₂SO₄-treated leaves and roots were also analyzed after 24 h of treatment. The results showed that salt stress resulted in significant reductions in leaf relative water content in seedlings and inhibited root elongation growth, with Na₂SO₄ treatment producing a greater impact on plant growth than NaCl treatment. Salt stress significantly alters ion transport and distribution in Thinopyrum ponticum, characterized by pronounced Na⁺ accumulation and a concomitant decline in K⁺ uptake. Additionally, to adapt to salt stress, roots enhance their ability to absorb and transport essential cations, such as Ca²⁺, Mg²⁺, Fe³⁺, and Cu²⁺. RNA-Seq analysis identified 1682 and 2816 differentially expressed genes (DEGs) in leaves and roots under Na₂SO₄ stress, respectively, with 210 common DEGs. Enrichment analyses revealed that DEGs were primarily associated with redox homeostasis, ion balance, and signal transduction. Furthermore, transcription regulation analysis indicated the Thinopyrum ponticum can coordinate the activation of NAC/MYB/WRKY transcription factors, SA/ETH hormone signaling, and Ca²⁺ pathways in response to salt stress. In summary, this study systematically reveals for the first time the molecular mechanisms by which Thinopyrum ponticum responds to Na₂SO₄ stress through coordinated regulation of ion transport, transcription factor networks, and hormone-Ca²⁺ signaling pathways. Based on transcriptomic and protein–protein interaction analyses, nine key candidate genes for saline–alkali tolerance were identified, including UGT7472, JMT, T4E14.7, CAX5, CP1, PXG2 NAMT1, BON3, and APX7. These findings provide novel genetic resources and a theoretical foundation for breeding salt–alkali-tolerant crops.