Search Results (9)

This study aimed to evaluate the effects of different crop cultivation practices on soil chemical properties and microbial communities in the Mu Us Desert, with the goal of optimizing land management and promoting ecological restoration. A one-way randomized block design was used to establish experimental plots for a cereal (Setaria italica, SI), a legume (Glycine max, GM), and a control group with no crops (CK) in the central Mu Us Desert. Soil samples were collected to assess physicochemical properties and to analyze microbial community structures via high-throughput 16S rRNA gene sequencing. Results showed that crop cultivation decreased soil pH while increasing soil organic carbon (SOC), total nitrogen (TN), and available phosphorus (AP), indicating improved soil fertility and reduced soil alkalinity. The composition of soil bacterial communities varied significantly among treatments. Both SI and GM treatments increased the number of operational taxonomic units (OTUs), enhancing bacterial richness and diversity. Proteobacteria and Actinobacteria increased with crop cultivation, whereas Chloroflexi declined. These shifts were largely attributed to changes in pH and nutrient availability. Notably, SI treatment had a stronger positive effect on bacterial richness. Correlation analyses between soil chemical properties and microbial community composition highlighted the potential of crop cultivation to influence soil ecosystem services. These findings provide a scientific basis for sustainable agricultural practices and ecological restoration in arid regions such as the Mu Us Desert. Further studies are warranted to investigate the functional roles of microbial communities under different cropping patterns. Full article

Eremosparton songoricum (Litv.) Vass. is a desert legume exhibiting extreme drought tolerance and the ability to withstand various harsh environments, making it a good candidate for investigating stress tolerance mechanisms and exploring valuable stress-resistant genes. However, the absence of a genetic transformation system for E. songoricum poses significant limitations for functionally validating these stress-resistant genes in situ. In this study, we developed an Agrobacterium-mediated transient transformation system for E. songoricum utilizing the β-glucuronidase (GUS) gene as a reporter. We investigated three types of explants (seedlings, assimilated branches and callus) and the effects of different Agrobacterium strains, seedling ages, OD₆₀₀ values, acetosyringone (AS) concentrations, sucrose concentrations and infection times on the transformation efficiency. The results reveal that the optimal transformation system was infecting one-month-old regenerating assimilated branches with the Agrobacterium strain C58C1. The infection solution comprised 1/2 MS medium with 3% sucrose and 200 μM AS at an OD₆₀₀ of 0.8, infection for 3 h and then followed by 2 days of dark cultivation, which achieving a maximum transformation rate of 97%. The maximum transformation rates of the seedlings and calluses were 57.17% and 39.51%, respectively. Moreover, we successfully utilized the assimilated branch transient transformation system to confirm the role of the previously reported transcription factor EsDREB2B in E. songoricum. The overexpression of EsDREB2B enhanced drought tolerance by increasing the plant’s reactive oxygen species (ROS) scavenging capacity in situ. This study established the first transient transformation system for a desert legume woody plant, E. songoricum. This efficient system can be readily applied to investigate gene functions in E. songoricum. It will expedite the exploration of genetic resources and stress tolerance mechanisms in this species, offering valuable insights and serving as a reference for the transformation of other desert plants and woody legumes. Full article

Eremosparton songoricum (Litv.) Vass. is a rare and extremely drought-tolerant legume shrub that is distributed in Central Asia. E. songoricum naturally grows on bare sand and can tolerate multiple extreme environmental conditions. It is a valuable and important plant resource for desertification prevention and environmental protection, as well as a good material for the exploration of stress tolerance mechanisms and excellent tolerant gene mining. However, the regeneration system for E. songoricum has not yet been established, which markedly limits the conservation and utilization of this endangered and valuable desert legume. Assimilated branches derived from seedlings were cultured on several MS mediums supplemented with various concentrations of TDZ or 6-BA in different combinations with NAA. The results showed that the most efficient multiplication medium was MS medium supplemented with 0.4 mg/L 6-BA and 0.1 mg/L NAA. The most efficient rooting medium was WPM + 25 g/L sucrose. The highest survival rate (77.8%) of transplantation was achieved when the ratio of sand to vermiculite was 1:1. In addition, the optimal callus induction medium was MS + 30 g/L sucrose + 2 mg/L TDZ + 0.5 mg/L NAA in darkness. The E. songoricum callus treated with 100 mM NaCl and 300 mM mannitol on MS medium could be used in proper salt and drought stress treatments in subsequent gene function tests. A rapid and efficient regeneration system for E. songoricum that allowed regeneration within 3 months was developed. The protocol will contribute to the conservation and utilization of this rare and endangered desert stress-tolerant species and also provide a fundamental basis for gene functional analysis in E. songoricum. Full article

Velvet mesquite (Prosopis velutina) is a native legume of the southwestern United States and northwestern Mexico, contributing significantly to the desert ecosystem and playing key ecological roles. It is also an important cause of allergic respiratory disease widely distributed in the Sonoran, Chihuahuan, and Mojave Deserts. However, no allergens from velvet mesquite pollen have been identified to date. Pollen proteins were extracted and analyzed by one- and two-dimensional electrophoresis and immunoblotting using a pool of 11 sera from mesquite-sensitive patients as the primary antibody. IgE-recognized protein spots were identified by mass spectrometry and bioinformatics analysis. Twenty-four unique proteins, including proteins well known as pollen, food, airway, or contact allergens and four proteins not previously reported as pollen allergens, were identified. This is the first report on allergenic proteins in velvet mesquite pollen. These findings will contribute to the development of specific diagnosis and treatment of mesquite pollen allergy. Full article

The mimosoid legumes are a clade of ~40 genera in the Caesalpinioideae subfamily of the Fabaceae that grow in tropical and subtropical regions. Unlike the better studied Papilionoideae, there are few genomic resources within this legume group. The tree Prosopis cineraria is native to the Near East and Indian subcontinent, where it thrives in very hot desert environments. To develop a tool to better understand desert plant adaptation mechanisms, we sequenced the P. cineraria genome to near-chromosomal assembly, with a total sequence length of ~691 Mb. We predicted 77,579 gene models (76,554 CDS, 361 rRNAs and 664 tRNAs) from the assembled genome, among them 55,325 (~72%) protein-coding genes that were functionally annotated. This genome was found to consist of over 58% repeat sequences, primarily long terminal repeats (LTR-)-retrotransposons. We find an expansion of terpenoid metabolism genes in P. cineraria and its relative Prosopis alba, but not in other legumes. We also observed an amplification of NBS-LRR disease-resistance genes correlated with LTR-associated retrotransposition, and identified 410 retrogenes with an active burst of chimeric retrogene creation that approximately occurred at the same time of divergence of P. cineraria from a common lineage with P. alba~23 Mya. These retrogenes include many biotic defense responses and abiotic stress stimulus responses, as well as the early Nodulin 93 gene. Nodulin 93 gene amplification is consistent with an adaptive response of the species to the low nitrogen in arid desert soil. Consistent with these results, our differentially expressed genes show a tissue specific expression of isoprenoid pathways in shoots, but not in roots, as well as important genes involved in abiotic salt stress in both tissues. Overall, the genome sequence of P. cineraria enriches our understanding of the genomic mechanisms of its disease resistance and abiotic stress tolerance. Thus, it is a very important step in crop and legume improvement. Full article

Soil salinity and drought are the two major challenges agriculture is facing in marginal environments, such as desert areas, which limit the growth and productivity of traditional cultivated crop species. In the Sahara Desert of the southern region of Morocco, livestock is the major agricultural activity, and forage supply is severely affecting livestock production. Blue panicum (Panicum antidotale Retz.) is an alternative salt-tolerant crop recently introduced to Morocco’s Sahara to enhance forage availability for livestock. The aim of this study was to increase the productivity and nutritional quality of blue panicum through the use of integrated agronomic practices, such as planting methods (bed or flat), crop establishment (direct seeding, transplantation, and rhizome propagation), organic and/or mineral amendments, and grass–legumes intercropping. The preliminary results showed that in the highly saline conditions, the combined application of organic amendments, seedling transplanting, and bed planting method gave the highest production (56 t/ha/year) of fresh biomass, which is higher than 50% compared to the control. This study suggests that in the southern region of Morocco and the Sahara Desert, the adoption of the blue panicum with integrated agronomic practices sustains livestock production. Full article

More efficient use of soil resources, such as nitrogen (N) and phosphorus (P), can improve plant community resistance and resilience against drought in arid and semi-arid lands. Intercropping of legume and non-legumes can be an effective practice for enhancing P mineralization uptake, and plant nutrient status. However, it remains unclear how intercropping systems using desert plant species impact soil-plant P fractions and how they affect N and water uptake capacity. Alhagi sparsifolia (a legume) and Karelinia caspia (a non-legume) are dominant plant species in the Taklamakan Desert in Xinjiang Province, China. However, there is a lack of knowledge of whether these species, when intercropped, can trigger synergistic processes and mechanisms that drive more efficient use of soil resources. Thus, in a field experiment over two years, we investigated the impact of monoculture and intercropping of these plant species on soil-plant P fractions and soil-plant nutrients. Both plant species’ foliar nutrient (N, P, and K) concentrations were higher under monoculture than intercropping (except K in K. caspia). Nucleic acid P was higher in the monoculture plots of A. sparsifolia, consistent with higher soil labile P, while metabolic P was higher in monoculture K. caspia, associated with higher soil moderately labile Pi. However, both species had a higher residual P percentage in the intercropping system. Soils from monoculture and intercropped plots contained similar microbial biomass carbon (MBC), but lower microbial biomass N:microbial biomass phosphorus (MBN:MBP) ratio associated with reduced N-acetylglucosaminidase (NAG) activity in the intercropped soils. This, together with the high MBC:MBN ratio in intercropping and the lack of apparent general effects of intercropping on MBC:MBP, strongly suggest that intercropping improved microbe N- but not P-use efficiency. Interestingly, while EC and SWC were higher in the soil of the K. caspia monoculture plots, EC was significantly lower in the intercropped plots. Plants obtained better foliar nutrition and soil P mineralization in monocultures than in intercropping systems. The possible positive implications of intercropping for reducing soil salinization and improving soil water uptake and microbial N-use efficiency could have advantages in the long term and its utilization should be explored further in future studies. Full article

Convergence is commonly caused by environmental filtering, severe climatic conditions and local disturbance. The basic aim of the present study was to understand the pattern of leaf traits across diverse desert plant species in a common garden, in addition to determining the effect of plant life forms (PLF), such as herb, shrub and subshrub, phylogeny and soil properties on leaf traits. Six leaf traits, namely carbon (C), nitrogen (N), phosphorus (P), potassium (K), δ¹³C and leaf water potential (LWP) of 37 dominant desert plant species were investigated and analyzed. The C, N, K and δ¹³C concentrations in leaves of shrubs were found higher than herbs and subshrubs; however, P and LWP levels were higher in the leaves of subshrubs following herbs and shrubs. Moreover, leaf C showed a significant positive correlation with N and a negative correlation with δ¹³C. Leaf N exhibited a positive correlation with P. The relationship between soil and plant macro-elements was found generally insignificant but soil C and N exhibited a significant positive correlation with leaf P. Taxonomy showed a stronger effect on leaf C, N, P and δ¹³C than soil properties, explaining >50% of the total variability. C₃ plants showed higher leaf C, N, P, K and LWP concentration than C₄ plants, whereas C₄ plants had higher δ¹³C than C₃ plants. Legumes exhibited higher leaf C, N, K and LWP than nonlegumes, while nonlegumes had higher P and δ¹³C concentration than legumes. In all the species, significant phylogenetic signals (PS) were detected for C and N and nonsignificant PS for the rest of the leaf traits. In addition, these phylogenetic signals were found lower (K-value < 1), and the maximum K-value was noted for C (K = 0.35). The plants of common garden evolved and adapted themselves for their survival in the arid environment and showed convergent variations in their leaf traits. However, these variations were not phylogenetics-specific. Furthermore, marks of convergence found in leaf traits of the study area were most likely due to the environmental factors. Full article

Alfalfa is one of the most nutritive and high-yielding forage legumes planted in rotation with cereal crops across the United States. Under semiarid and arid climates with limited water resources, sustainable management of the available resources is required. The objective of this study was to investigate the effect of different irrigation regimes and fungicide applications on alfalfa in the high desert region of the Colorado Plateau of the U.S. Field experiments were conducted during the 2012–2014 period. Alfalfa was planted in fall 2012, uniformly irrigated for crop establishment and subjected to seven different irrigation regimes after the first cut in spring 2013. Alfalfa was treated by fungicide application and was harvested at 10% blooming. The maximum amounts of applied water were 350, 300, 208, and 312 mm, respectively, during the first, second, third, and fourth regrowth cycles in 2013, and 373, 282, 198, and 246 mm in 2014 for the respective regrowth cycles in 2014; the seasonal applied irrigation amount varied from 711 to 1171 mm in 2013 and from 328 to 1100 mm in 2014. The results showed non-significant effect of fungicide application on the forage yield. Alfalfa forage yield was significantly affected by the irrigation regimes and showed a third order polynomial relationship with the applied irrigation amounts during each regrowth cycle and on seasonal scale. Forage yield decreased from the first cut to the fourth cut and the annual forage varied from 10.6 to 25.7 Mg/ha for the treated alfalfa and from 11.5 to 25.6 Mg/ha for the non-treated alfalfa. Forage yield at each cut accounted for 39.6, 24.2, 17.6, and 18.6% of the 2013 season forage yield and 31.4, 23.8, 21.6, and 23.2% of the 2014 season forage yield, for the first, second, third, and fourth cut, respectively. Alfalfa water use efficiency varied from 0.06 to 3.3 kg/m³. The relationships developed in this study could be used by forage growers, crop consultants, and project managers for decision making and planning to improve the productivity of water under the semiarid and arid climate of New Mexico and the surrounding regions. Full article