High-temperature stress negatively affects the growth and development of plants, and therefore threatens global agricultural safety. Cultivating stress-tolerant plants is the current objective of plant breeding programs. Pearl millet is a multi-purpose plant, commonly used as a forage but also an important food staple. This crop is very heat-resistant and has a higher net assimilation rate than corn under high-temperature stress. However, the response of heat resistant pearl millet has so far not been studied at the transcriptional level. In this study, transcriptome sequencing of pearl millet leaves exposed to different lengths of heat treatment (1 h, 48 h and 96 h) was conducted in order to investigate the molecular mechanisms of the heat stress response and to identify key genes related to heat stress. The results showed that the amount of heat stress-induced DEGs in leaves differs with the length of exposure to high temperatures. The highest value of DEGs (8286) was observed for the group exposed to heat stress for 96 h, while the other two treatments showed lower DEGs values of 4659 DEGs after 1 h exposure and 3981 DEGs after 48 h exposure to heat stress. The DEGs were mainly synthesized in protein folding pathways under high-temperature stress after 1 h exposure. Moreover, a large number of genes encoding ROS scavenging enzymes were activated under heat stress for 1 h and 48 h treatments. The flavonoid synthesis pathway of pearl millet was enriched after heat stress for 96 h. This study analyzed the transcription dynamics under short to long-term heat stress to provide a theoretical basis for the heat resistance response of pearl millet.

Pennisetum alopecuroides (L.), one of the important exotic plants, gives great economic value to animal husbandry in China. In order to study the distribution of Pennisetum alopecuroides (L.) in China and its response to climate change, based on the distribution records of Pennisetum alopecuroides (L.), our study used the Maximum Entropy (MaxEnt) model and geographic information system (GIS) methods, combined with environmental factors such as climate and terrain, to predict the potential distribution areas suitable for Pennisetum alopecuroides (L.) under current and future climate scenarios. The results showed that annual precipitation was the most important factor affecting the distribution of Pennisetum alopecuroides (L.). In current climate scenario, the total area of suitable for Pennisetum alopecuroides (L.) growth was about 576.5 km², accounting for about 60.5% of the total land area of China. Among all the suitable areas, the area of low, middle and high fitness areas accounted for 5.69%, 20.55% and 33.81% of the total area respectively. In future climate scenarios (RCP4.5), the suitable area of Pennisetum alopecuroides (L.) would decrease with climate change, showing a clear trend of northward expansion in China. A concentrated and contiguous distribution region for Pennisetum alopecuroides (L.) would appear in northeast China. The model was tested by the receiver operating characteristic curve (ROC), and the average area under the curve of ROC of the training set was 0.985, which was reliable. This work provided an important reference and theoretical basis for the efficient utilization and plant regionalization of Pennisetum alopecuroides (L.) in future.

Microorganisms have important ecological functions in ecosystems. Reseeding is considered as one of the main strategies for preventing grassland degradation in China. However, the response of soil microbial community and diversity to reseeding grassland (RG) and natural grassland (NG) remains unclear, especially in the Songnen Meadow. In this study, the soil microbial community compositions of two vegetation restoration types (RG vs NG) were analyzed using a high-throughput sequencing technique. A total of 23,142 microbial OTUs were detected, phylogenetically derived from 11 known bacterial phyla. Soil advantage categories includedProteobacteria,Acidobacteria,Actinobacteria, andBacteroidetes, which together accounted for > 78% of the all phyla in vegetation restoration. The soil microbial diversity was higher in RG than in NG. Two types of vegetation restoration had significantly different characteristics of soil microbial community (P< 0.001). Based on a molecular ecological network analysis, we found that the network in RG had a longer average path distance and modularity than in NG network, making it more resilient to environment changes. Meanwhile, the results of the canonical correspondence analysis and molecular ecological network analysis showed that soil pH (6.34 ± 0.35 in RG and 7.26 ± 0.28 in NG) was the main factor affecting soil microbial community structure, followed by soil moisture (SM) in the Songnen meadow, China. Besides, soil microbial community characteristics can vary significantly in different vegetation restoration. Thus, we suggested that it was necessary and reasonable for this area to popularize reseeding grassland in the future.

Aims Continuous cropping is a common cropping practice in northeast China. This practice can positively or negatively impact soil microbial community. However, the response of rhizosphere microbial community structures, specific microbial taxa, and co-occurrence patterns to different continuous cropping systems are rarely tested.Methods In this study, soil samples were collected from the rhizosphere of three different continuous cropping systems (Corn, Alfalfa and Sheepgrass) were analyzed for microbial community (bacterial and fungal) composition and structural responses using an Illumina HiSeq high-throughput sequencing technique.Results Our results revealed that the α- and β-diversity indices of the fungal communities were significantly different across the three continuous cropping systems. The analysis of the molecular ecological network revealed that Alfalfa communities had the highest number of nodes and edges in the bacterial network while Sheepgrass had the highest number of nodes and edges in the fungal network. To distinguish differences between the co-occurring taxa among the three cropping systems, we compared the number of positive and negative links within and between microbial groups. This highlights that perennial grassland systems had more complex bacterial and inter-domain networks. Our inter-domain networks also revealed the predominant role of fungi as a key taxon in soil microbiome networks across the three land-use types.Conclusions Our results demonstrated that continuous cropping of perennial forage crops enhanced soil microbial diversity, network complexity and multifunctionality. Moreover, changes in microbiota characteristics are positively dependent on forage-induced changes in soil multifunctionality.

Long-term continuous monoculture is a common practice in modern agricultural production, yet its effects on soil microbial communities—particularly the differences between annual crops and perennial forages—remain poorly understood. Here, we investigated the diversity, composition, and co-occurrence networks of soil bacterial and fungal communities under three long-term continuous monoculture systems in Northeast China: corn (annual crop, with fertilizer application), alfalfa (perennial legume forage, without fertilizer), and sheepgrass (perennial grass forage, without fertilizer). Fungal α- and β-diversity indices differed significantly across the three systems, whereas bacterial α-diversity showed no significant differences among them. The dominant bacterial phyla were Proteobacteria, Acidobacteria, Actinobacteria, and Gemmatimonadetes, while Ascomycota, Basidiomycota, and Glomeromycota were the most abundant fungal taxa. Co-occurrence network analysis revealed system-specific patterns: the bacterial network exhibited the highest number of nodes and edges in alfalfa, whereas the fungal network was most complex in sheepgrass. The ratio of positive to negative edges in the bacterial network was more than three times higher in alfalfa than in the other systems, while the fungal network showed the highest positive-to-negative link ratio in sheepgrass. Inter-domain associations were predominantly characterized by a higher number of edges in sheepgrass. Our findings demonstrate that perennial forage systems (alfalfa and sheepgrass) promote more complex bacterial and inter-domain microbial networks compared to the annual corn system. These differences in network may have important implications for soil ecosystem functions mediated by microbial communities, highlighting the potential benefits of incorporating perennial forages into long-term monoculture systems to enhance soil microbial interactions and ecosystem sustainability.

Litter decomposition is a key process in carbon (C) and nutrient cycling, but how nitrogen (N) addition affects decomposition via soil properties versus altered litter quality remains unclear. We conducted a 30-day laboratory incubation using litter from three grassland species ( Poa annua , Lolium perenne , Dactylis glomerata ) and soils from a four-year N addition field experiment (0, 1.49, 2.99, 5.99 g N·m ^-2 ·yr ^-1 ) in a subtropical grassland of Southwest China. Because all litter was collected from unfertilized areas, our experiment specifically tested the soil legacy effects of N addition on decomposition of standardized litter, not the direct effects on litter quality. Decomposition rates (decay constant k) ranged from 0.017 day ^-1 ( P. annua , no N) to 0.068 day ^-1 ( L. perenne , high N). N addition significantly increased decomposition for all species, with the strongest stimulation for low-quality litter ( P. annua ). First-order kinetic models fitted the 30-day data well (R² > 0.98), but extrapolation beyond the incubation period is not justified. Initial C:N ratio was negatively correlated with both k ( r = –0.625, P < 0.01) and cumulative CO ₂ efflux significantly influenced by both species identity and N addition. Our design does not allow attribution of the stimulation to N-induced changes in litter quality. Instead, long-term N addition altered soil properties (increased inorganic N, reduced pH), which in turn modulated decomposition of subsequently added litter. We conclude that soil legacy effects of N addition accelerate litter decomposition and CO ₂ efflux, with effects modulated by litter quality. These findings provide empirical evidence for predicting ecosystem C dynamics under future N deposition but highlight the need for longer-term experiments that directly manipulate both soil properties and litter chemistry.