Sand Rice Research Articles

Nutrition, health benefits, and processing of sand rice (Agriophyllum squarrosum): Comparisons with quinoa and buckwheat.

The dual pressures of climate change and population growth have made the development of new grains a necessity. Agriophyllum squarrosum (sand rice) has high adaptability to harsh environments and does not occupy agricultural land. It is widely cultivated and consumed in Central Asia. Sand rice, together with quinoa and buckwheat, belongs to the same pseudocereals group with rich nutritional value and gluten-free properties; however, its nutritional composition and health benefits differ from those of quinoa and buckwheat. Sand rice seeds are a rich source of nutrients and bioactive compounds, including proteins, amino acids, unsaturated fatty acids, and crude fiber, which are similar to those in buckwheat and quinoa; however, their starch content is relatively low. Sand rice seeds also possess phenolic acids and flavonoids, which exhibit antioxidant, anticancer, anti-diabetes, and anti-inflammatory properties. Furthermore, sand rice extracts are considered suitable for treating some chronic diseases. Overall, sand rice is considered a good plant-based food that can be used to develop various functional foods and beverages or mixed with other grains in different recipes. However, advancements in the processing technology of sand rice-based foods are required to fully exploit the potential of sand rice in the food industry to improve human health. This review analyzes the current understanding of the nutritional content of sand rice by comparing it with that of quinoa and buckwheat. Furthermore, its potential medicinal activity and feasibility as a functional ingredient to improve food quality is discussed.

Phenotypic variation in hypocotyl elongation among elite sand rice (Agriophyllum squarrosum) lines.

Sand rice (Agriophyllum squarrosum), widely distributed in Central Arid Asia and prevalent in the sand dunes of northern China, presents a promising potential as a climate-resilient crop. The plasticity of hypocotyl growth is the key trait for sand rice to cope with wind erosion and sand burial, ensure seedling emergence, and determine plant architecture. In this study, we assessed the overall hypocotyl phenotype of six sand rice elite lines, which were collected from different regions of northern China, and selected by our group over past decade through common garden trials. Significant phenotypic variations were observed in thousand-seed weight (TSW), seedling emergence percentage, hypocotyl length and diameter, and seedling fresh weight among the lines. The elite line Aerxiang (AEX) exhibited excellent agronomic performance with superior and synchronous emergence, and high survival percentage, distinguishing itself as a prime candidate for further large-scale cultivation. Contrastingly, the lines from the arid regions showed markedly lower performance. Partial Least Squares Path Modeling (PLSPM) was used to assess the impact of seed provenance climate factors, including annual mean temperature (AMT) and annual mean precipitation (AMP), on trait variability among lines. The findings indicate a significant correlation between climate factors and hypocotyl length, highlighting the intricate adaptation of sand rice to local climate. The comprehensive understanding of the mechanisms behind phenotypic variations offers valuable insights for sand rice de novo domestication and innovative germplasm resources, and lays the foundation for ecological restoration in sandy areas.

A BBCH‐scale code for the phenology of sand rice (Agriophyllum squarrosum (L.) Moq.)

AbstractSand rice (Agriophyllum squarrosum (L.) Moq.), an annual psammophyte, is a promising wild plant for de novo domestication. Although many related studies have been documented recently, a basic phenological scale describing its growth stages is lacking. To address this gap, we have defined nine principal growth stages, each subdivided into several secondary stages according the international BBCH coding system. The growth stages mainly include seedling emergence, leaf development, formation of the primary branches, main stem elongation, inflorescence emergence, flowering, fruit development, ripening and senescence. Importantly, the growth sequence of sand rice reveals a distinctive stage, coded as BBCH21, characterized by the elongation of the first pair of primary branches, which occurs prior to main stem visible (BBCH30). This branch priority phenotype in sand rice strongly challenges the generally recognized growth pattern of ‘apical dominance’ in dicotyledons. The sequential and chronological progression of principal growth stages of sand rice was further determined in an experimental field with a representative genotype from the Tengger desert of Northwest China in 2023. The establishment of BBCH scale of sand rice lays a methodological foundation for morphological assessment among different germplasms and between wild‐type and mutant plants. This will accelerate the de novo domestication process of sand rice using natural selection and artificial mutagenesis.

Effect of superheated steam treatment on enzyme inactivation, morphostructural, physicochemical and digestion properties of sand rice (Agriophyllum squarrosum) flour

The lipase (LA) and peroxidase (POD) activities, as well as morphological structure, physicochemical and digestion properties of sand rice flour (SRF) treated with superheated steam (SS), were investigated. SS treatment at 165 °C completely deactivated LA and resulted in a 98% deactivation of POD activities in SRF. This treatment also intensified gelatinization, induced noticeable color alterations, and decreased pasting viscosities. Furthermore, there was a moderate reduction in crystal structure, lamellar structure, and short-range ordered structure, with a pronounced reduction at temperatures exceeding 170 °C. These alterations significantly impacted SRF digestibility, leading to increased levels of rapidly digestible starch (RDS) and resistant starch (RS), with the highest RS content achieved at 165 °C. The effectiveness of SS treatment depends on temperature, with 165 °C being able to stabilize SRF with moderate changes in color and structure. These findings will provide a scientific foundation for SS applicated in SRF stabilization and modification.

Effect of endogenous protein and lipid removal on the physicochemical and digestion properties of sand rice (Agriophyllum squarrosum) flour

The study investigated the effect of removing protein and/or lipid on the physicochemical characteristics and digestibility of sand rice flour (SRF). Morphological images showed that protein removal had a greater impact on exposing starch granules, while lipids acted as an adhesive. The treatment altered starch content in SRF samples, leading to increased starch crystallinity, denser semi-crystalline region, lower onset gelatinization temperature (To), higher peak viscosity and gelatinization enthalpy (ΔH), where Protein removal showed a more pronounced effect on altering physicochemical properties compared to lipid removal. The research revealed a positive correlation between rapidly digestible starch (RDS), maximum degree of starch hydrolysis (C∞), digestion rate constant (k) values and 1047/1022 cm−1 ratio, showing a strong connection between short-range structure and starch digestibility. The presence of endogenous proteins and lipids in SRF hinder digestion by restricting starch swelling and gelatinization, and physically obstructing enzyme-starch interaction. Lipids had a greater impact on starch digestibility than proteins, possibly due to their higher efficacy in reducing digestibility, higher lipid content with greater potential to form starch-lipid complexes. This study provides valuable insights into the interaction between starch and proteins/lipids in the sand rice seed matrix, enhancing its applicability in functional and nutritional food products.

Sand rice, a promising future crop for desert and marginal lands in northern China

AbstractThe pioneer Amaranthaceae species sand rice (Agriophyllum squarrosum) is an annual psammophyte that is widely distributed in the deserts and sand fields of northern China. The well‐balanced nutritional values, long consumption history, and extreme stress tolerance of sand rice have fascinated scientists, prompting its development as a climate‐resilient crop. Sand rice has been successfully introduced and cultivated on sandy and loess lands over the past decade, while large‐scale artificial planting has been carried out in the Ulan Buh and Tengger deserts. However, the yield is far below the maximum potential, as estimated by the highest yield per plant ever found in the Tengger desert during our survey of wild populations. The current domestication of sand rice relies mainly on natural selection and mutagenesis breeding. A few elite lines with modified agronomic traits, such as compact architecture, high productivity, reduced trichomes, and short plant stature, have been developed from natural populations and a chemical mutagenesis library. Breeding new cultivars and broader cultivation of sand rice in deserts and marginal lands will stimulate economic growth and diversify the food supply, especially for the area west of the Hu Huanyong Line, thus contributing to environmental sustainability in northern China.

Influence of sand rice (Agriophyllum squarrosum) flour substitution on the physicochemical properties, bioactive activities, and in vitro digestibility of wheat bread

SummarySand rice (Agriophyllum squarrosum), as the seed of an annual spermaphyte, is generally concerned for its highly valuable nutrients. This study aimed to evaluate the effects of sand rice (SR) supplementation on the physicochemical properties, bioactive activities, and in vitro digestibility of wheat flour bread. Results showed that the addition of SR could significantly increase the total phenolic, flavonoid content, and antioxidant activity. Moreover, the SR‐added bread had lower pasting viscosity and enthalpy of gelatinisation. In vitro starch digestion assay showed a higher slow digestion starch content and performed a lower digestibility rate in SR bread, while, in terms of 20% or higher addition levels, bread quality was negatively affected by SR regarding aspect ratio, specific volume, colour profiles, texture properties, and sensory evaluation. Overall, these results indicated that sand rice flour could be a fine replacement for wheat flour in bread formulations to increase the product's nutritional values and functional properties.

Long-term feeding of sand rice (Agriophyllum squarrosum seed) can improve the antioxidant capacity of mice

Unhealthy eating habits with sugar-rich and high-fat foods can bring nutritional imbalance and other chronic diseases. At present, there is an increasing demand in regulating human sub-health through functional foods. Agriophyllum squarrosum (L.) Moq., a pioneer plant native to sand dunes with ecological restoration function, is a traditional food plant of sand regions and Mongolian folk medicine. Numerous studies have confirmed that A. squarrosum seed, also called sand rice, has high nutritional value. However, the long-term health effects of eating sand rice remain unclear. To better explore and evaluate its long-term effects, hereby, ICR mice were fed with sand rice flour at different ratios (control, 60% and 95%) for 100 days. Results show that the growth and blood glucose level curve of these experimental mice were lower and more stable than that of the control. In addition, mice fed pure sand rice ingredient (95%) gained more stable body weight and blood glucose after 28 days, which revealed that sand rice is a food with comprehensive nutritional value and rarely negatively impacts the body growth performance. Our data also demonstrates that, the content of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) provided the lowest level in the blood of mice with a diet of pure sand rice ingredient, 0.48, 4.14, 0.91, 3.03 mmol/L, respectively. Also, T-SOD and GSH-PX activity provided a high level in mice with pure sand rice gradient, which significantly increased by 36% (T-SOD) and 19% (GSH-PX) compared to the control. These results suggest that long term intake of the pure sand rice ingredients is more helpful for stabilizing blood lipid and improve antioxidant capacity and beneficial to people suffering from chronic disease. This study supplies the first animal evidence to support the claim that sand rice is a promising functional food with comprehensive nutrition in the future. We are confident that, with increasing demands of daily sand rice usage, planting A. squarrosum in the vast desert regions will further increase the local economy and ecological restoration when coping with global warming.

<italic>De novo</italic> domestication and preliminary cultivar development of sand rice (<italic>Agriophyllum squarrosum</italic>), a sand dune pioneer species

<p indent="0mm">The comprehensive utilization of desert plants and sandy land resources is of far-reaching significance to the eco-civilization progress and food security in the arid region of northern China. The pioneer species <italic>Agriophyllum squarrosum</italic> is broadly distributed on the mobile sand dunes in the arid and semi-arid areas of northern China. Its seed, also called sand rice, has well-balanced nutritional values and has been consumed for more than <sc>1300 years.</sc> In 2010, our group first initiated the domestication research of sand rice by investigating the various historical literature and food consuming records of sand rice. Genetic modification and breeding are currently dependent on natural populations and artificial mutagenesis. A few modified lines with better agronomic traits have been initially isolated, laying a material foundation for further cultivation evaluation in different areas and cultivar declaration. However, the speed domestication of sand rice still requires systematically analyzing phenotypic variation among different germplasms, the establishment of a genetic transformation system, and isolating elite lines with a synchronous germination rate and strong seedling vigor.

Supplementing Diets with Agriophyllum squarrosum Reduced Blood Lipids, Enhanced Immunity and Anti-Inflammatory Capacities, and Mediated Lipid Metabolism in Tan Lambs.

Agriophyllum squarrosum (sand rice), a widespread desert plant, possesses anti-hyperglycemic and anti-inflammatory properties, and has been used in traditional Chinese medicine for many years. However, its effects on ruminants are unknown. To fill this gap, we examined the effects of A. squarrosum on the immune and anti-inflammatory responses of lambs. A total of 23, 6-month-old Tan ewe-lambs (27.6 ± 0.47 kg) were divided into four groups and offered a basic diet (C-control), or a diet that contained 10%, 20%, or 30% A. squarrosum, on a dry matter basis, for 128 days. Serum concentrations of total cholesterol were lower (p = 0.004) in the 30% supplemented lambs than controls, while concentrations of high-density lipoprotein cholesterol were lower (p = 0.006) in the 10% and 20%, but not in 30% supplemented lambs than controls. Serum-cortisol concentrations were lower (p = 0.012) in the 30% supplemented lambs and free fatty acid concentrations were higher in the 10% and 20% supplemented lambs than in control lambs (p &lt; 0.001). Supplementation with A. squarrosum decreased (p &lt; 0.05) the area of adipocytes in subcutaneous adipose tissue, but there was no difference between the 20% and 30% diets. Conversely, the area in visceral adipose tissue (VAT) increased (p &lt; 0.05), especially for the 10% and 20% supplemented diets. Supplementation with A. squarrosum also enriched immune and anti-inflammatory related and lipid and glucose-metabolic pathways and associated differentially expressed gene expressions in adipose tissue. A total of 10 differential triacylglycerol, 34 differential phosphatidylcholines and seven differential phosphatidylethanolamines decreased in the diet with 30% supplementation, when compared to the other diets. Finally, adipocyte-differentiation genes, and immune and inflammatory response-related gene expression levels decreased in lamb adipocytes cultured with an aqueous A. squarrosum extract. In conclusion, supplementing lamb diets with A. squarrosum reduced blood lipids, enhanced immunity and anti-inflammatory capacities, and mediated lipid metabolism in adipose tissue and adipocytes of Tan lambs. A level of approximately 10% is recommended, but further research is required to determine the precise optimal level.

Precipitation and local environment shape the geographic variation of seed size across natural populations of sand rice (Agriophyllum squarrosum).

Sand rice (Agriophyllum squarrosum) is widely distributed on dunes in the Asian interior arid zone, and its large intraspecific trait variation makes it a very good model for investigating the ecological processes underlying its adaptation to the desert environment. In this study, seed size variation across 68 natural populations was used to establish geographic patterns and to quantify the effects of the climate, soil, and collection-year weather variables. The length of the seed major axis and thousand seed weight (TSW) both showed significant longitudinal patterns. Long-term climate variables accounted for most of the explained variances for seed major axis (57.20%) and TSW (91.54%). Specifically, annual precipitation and minimum monthly precipitation had the most significantly positive and negative effects, indicating that longitudinal clines are driven by a precipitation gradient across the species' distribution range. A substantial unique effect of soil variables (27.27%) was found for seed major axis variation, but only 3.64% of TSW variation was explained by soil variables. Two extreme groups were selected to evaluate the genetic and plastic effects on seed size in a common garden experiment. Large-seeded individuals were more competitive in semi-arid regions, and had stronger adaptive plasticity as well as better performance in early seedling establishment, and hence they have potential for use in future domestication projects.

Effect of heat-moisture treatment on the structural and physicochemical characteristics of sand rice (Agriophyllum squarrosum) starch.

A small granule starch from sand rice (Agriophyllum squarrosum) was subjected to heat‐moisture treatment (HMT) at different moisture contents (MCs,15%–30%). With MC≤20%, a higher MC resulted in increases in the starch orders (i.e., short‐range and crystalline structure) with unchanged granule morphology. Nonetheless, a further elevated MC (>20%) gradually destroyed the granule morphology and starch orders. Also, HMT gradually vanished the lamellar structure as MC increased during HMT. These structural evolutions in HMT‐modified starch resulted in greater thermal stability, higher pasting temperature, lower pasting viscosity and weakened digestibility. Particularly, HMT applied directly in sand rice starch at 20% MC obtained the highest amount of SDS and RS (23.6%), which was 2.2‐fold higher than that of native starch. Therefore, the small granule sand rice starch can be modulated by HMT through controlled MC to expand their application range in food production.

Genomic Adaptive Evolution of Sand Rice (Agriophyllum squarrosum) and Its Implications for Desert Ecosystem Restoration.

Natural selection is a significant driver of population divergence and speciation of plants. Due to local adaptation to geographic regions with ecological gradients, plant populations harbored a wide range of adaptive genetic variation to enable them to survive the heterogeneous habitats. This is all the more necessary for desert plants, as they must tolerant more striking gradients of abiotic stresses. However, the genomic mechanism by which desert plants adapt to ecological heterogeneity remains unclear, which could help to guide the sustainability of desert ecosystems. Here, using restriction-site-associated DNA sequencing in 38 natural populations, we investigated the genomic divergence and environmental adaptation of sand rice, Agriophyllum squarrosum, an annual pioneer species that covers sand dunes in northern China. Population genetic structure analyses showed that sand rice could be divided into three geographically distinct lineages, namely, Northwest, Central, and East. Phylogeographic analyses revealed that the plant might originate locally in Bergen County and further differentiated into the East lineage and then the Central lineage. Ecological niche modeling found that different lineages occupied distinct ecological niches, suggesting that the ecological gradient would have triggered genomic differentiation among sand rice lineages. Ecological association study supported that the three SNPs under divergent selection were closely correlated with precipitation gradients, indicating that precipitation might be the most important stress trigger for lineage diversity in sand rice. These adaptive SNPs could be used to genotype suitable germplasms for the ecological restoration of specific desertified lands. Further analyses found that genetic structure could significantly overestimate the signals for balancing selection. Within the Central lineage, we still found that 175 SNPs could be subject to balancing selection, which could be the means by which sand rice maintains genetic diversity and adapts to multiple stresses across heterogeneous deserts and sandy lands. From a genomic point of view, this study highlighted the local and global adaptation patterns of a desert plant to extreme and heterogeneous habitats. Our data provide molecular guidance for the restoration of desertified lands in the arid and semi-arid regions of China and could facilitate the marker assistant breeding of this potential crop to mitigate climate change.

The agronomic performance of sand rice (Agriophyllum squarrosum), a potential semi-arid crop species

Agriophyllum squarrosum (sand rice), a member of the Amaranthaceae family adapted to arid to semi-arid conditions in central Asia, produces highly nutritious seed. Three ecotypes collected from sand dunes in the western Chinese arid desert region (Linze, Minqin and Shapotou) and three from the semi-arid desert region (Duolun, Naiman, and Aerxiang) were grown in loess soil at an experimental station (Gaolan) to characterize their performance with respect to plant architecture and seed yield-associated traits. The ecotypes originating from the more arid sites developed into taller, more strongly branching plants, formed thicker stems and a greater number of spikes. Those collected from the semi-arid sites developed larger seeds and were of shorter duration. The highest seed yields were obtained from the Aerxiang ecotype (129.55 g/m2). The same ecotype also exhibited both the highest emergence rate and the most favorable harvest index. The study represents the first assessment of the agronomic performance of sand rice and shows what needs to be done to domesticate and improve the species before it can be considered as a viable crop species.

Synteny-based mapping of causal point mutations relevant to sand rice (Agriophyllum squarrosum) trichomeless1 mutant by RNA-sequencing

Sand rice (Agriophyllum squarrosum), a diploid Amaranthaceae species within the order Caryophyllalles, has potential as a crop in response to concerns about ongoing climate change and future food security. Modifying the weedy traits, such as dense trichomes, is important for the domestication of sand rice. In this study, an ethyl methanesulfonate (EMS) induced Agriophyllum squarrosum trichomeless mutant (astcl1) was isolated and genetic analysis revealed that this mutant was controlled by a single recessive locus. RNA sequencing was employed to analyze sequence variations between the mutant and wild-type individuals based on allele frequencies. Synteny-based mapping against two closely related and sequenced species finally delimited the causal mutations into an approximately 18.97 mega base pair (Mb) interval on the top portion of the chromosome 6 (Bv6) of sugar beet (Beta vulgaris) and two intervals (5.56 and 2.69 Mb) on the chromosomes 14 (CqA14) and 6 (CqB06) of quinoa (Chenopodium quinoa). These two quinoa intervals were located in the orthologous chromosomal regions against sugar beet Bv6. Differential expression analysis revealed that the astcl1 mutation only affects the expression of a small subset of genes. Most significantly, 17 lipid transport and metabolism related genes, such as GDSL esterases and very-long-chain 3-oxoacyl-CoA reductase 1, and two R2R3 MYB genes, MYB39 and RAX3, were down-regulated in astcl1 mutants. These results imply that the Astcl1 protein coordinately regulates trichome initiation and cuticle biosynthesis in sand rice.

Morphological description and DNA barcoding study of sand rice (Agriophyllum squarrosum, Chenopodiaceae) collected in Kazakhstan

BackgroundSand rice (Agriophyllum squarrosum (L.) Moq.) is an annual shrub-like plant adapted to the mobile sand dunes in desert and semi-desert regions of Asia. It has a balanced nutrient composition with relatively high concentration of lipids and proteins, which results in its nutrition being similar to legumes. Sand rice’s proteins contain the full range of essential amino acids. However, calories content is more similar to wheat. These features together with desert stress resistance make sand rice a potential food crop resilient to ongoing climate change. It is also an important fodder crop (on young stages of growth) for cattle in arid regions of Kazakhstan. In our work, sand rice samples were collected from two distant regions of Kazakhstan as a part of the nation-wide project to determine genetic variation of the native flora.ResultsSamples were collected in western and southeastern parts of Kazakhstan separated by distances of up to 1300 km. Sequences of the nuclear ribosomal DNA ITS1-5.8S-ITS2 region and the chloroplast matK gene confirmed the identity of species defined by morphological traits. Comparison with GenBank sequences revealed polymorphic sequence positions among Kazakh populations and GenBank references, and suggested a distinction among local populations of sand rice. The phylogenetic analysis of nucleotide sequences showed a clear partition of A. squarrosum (L.) Moq. from Agriophyllum minus Fisch. & C.A. Mey, which grows in the same sand dunes environment.ConclusionsDNA barcoding analyses of ITS and matK sequences showed a segregation of A. squarrosum from A. minus into separate clades in Maximum-Likelhood dendrograms. ITS analysis can be successfully used to characterize A. squarrosum populations growing quite distant from each other. The data obtained in this work provide the basis for further investigations on A. squarrosum population structure and may play a role in the screening of sand rice plants growing in desert and semi-desert environments of Central Asia and China.

SNP Discovery and Genetic Variation of Candidate Genes Relevant to Heat Tolerance and Agronomic Traits in Natural Populations of Sand Rice (Agriophyllum squarrosum).

The extreme stress tolerance and high nutritional value of sand rice (Agriophyllum squarrosum) make it attractive for use as an alternative crop in response to concerns about ongoing climate change and future food security. However, a lack of genetic information hinders understanding of the mechanisms underpinning the morphological and physiological adaptations of sand rice. In the present study, we sequenced and analyzed the transcriptomes of two individuals representing semi-arid [Naiman (NM)] and arid [Shapotou (SPT)] sand rice genotypes. A total of 105,868 pairwise single nucleotide polymorphisms (SNPs) distributed in 24,712 Unigenes were identified among SPT and NM samples; the average SNP frequency was 0.3% (one SNP per 333 base pair). Characterization of gene annotation demonstrated that variations in genes involved in DNA recombination were associated with the survival of the NM population in the semi-arid environment. A set of genes predicted to be relevant to heat stress response and agronomic traits was functionally annotated using the accumulated knowledge from Arabidopsis and several crop plants, including rice, barley, maize, and sorghum. Four candidate genes related to heat tolerance (heat-shock transcription factor, HsfA1d), seed size (DA1-Related, DAR1), and flowering (early flowering 3, ELF3 and late elongated hypocotyl, LHY) were subjected to analysis of the genetic diversity in 10 natural populations, representing the core germplasm resource across the area of sand rice distribution in China. Only one SNP was detected in each of HsfA1d and DAR1, among 60 genotypes, with two in ELF3 and four in LHY. Nucleotide diversity ranged from 0.00032 to 0.00118. Haplotype analysis indicated that the NM population carried a specific allele for all four genes, suggesting that divergence has occurred between NM and other populations. These four genes could be further analyzed to determine whether they are associated with phenotype variation and identify alleles favorable for sand rice breeding.

Phenotypic variation of a potential food crop, &amp;lt;italic&amp;gt;Agriophyllum squarrosum&amp;lt;/italic&amp;gt;, impacted by environmental heterogeneity

Agriophyllum squarrosum , also called “sand rice”, is a pioneer annual plant endemic to mobile sand dunes across the temperate deserts of China. It has attracted great interest due to its high agro-ecology value. In this paper, based on a common garden experiment with 26 populations of A. squarrosum , we investigated the relationship between the bio-climatic factors of the original habitat and a couple of important agronomic traits, including Plant height (PH), Seed weight (SW), Stem diameter (STD), Basal branch length (BBL), Aboveground biomass (AGB) and Seed diameter (SED). In general, all the phenotypic traits were significantly related to the latitudinal gradient. Except for SED, all of the traits were higher in the South group than the North group. This result suggested that the South group tends toward vegetative growth, while the North group tends toward reproductive growth. Based on 19 bio-climatic factors from DIVA-GIS, a redundancy analysis with Cannock software showed that the North group was more affected by precipitation, whereas the South group was more affected by temperature. This phenomenon indicates that the natural variations in growth characteristics and energy distribution among the populations of A. squarrosum have been largely impacted by local adaptation and genetic differentiation. Our work supports empirical data for better understanding the ecological genetic basis of how psammophytes adapt to heterogeneous environments and provide important germplasm resources and evaluation methods for the domestication and breeding of A. squarrosum .

Different Sets of Post-Embryonic Development Genes Are Conserved or Lost in Two Caryophyllales Species (Reaumuria soongorica and Agriophyllum squarrosum).

Reaumuria soongorica and sand rice (Agriophyllum squarrosum) belong to the clade of Caryophyllales and are widely distributed in the desert regions of north China. Both plants have evolved many specific traits and adaptation strategies to cope with recurring environmental threats. However, the genetic basis that underpins their unique traits and adaptation remains unknown. In this study, the transcriptome data of R. soongorica and sand rice were compared with three other species with previously sequenced genomes (Arabidopsis thaliana, Oryza sativa, and Beta vulgaris). Four different gene sets were identified, namely, the genes conserved in both species, those lost in both species, those conserved in R. soongorica only, and those conserved in sand rice only. Gene ontology showed that post-embryonic development genes (PEDGs) were enriched in all gene sets, and different sets of PEDGs were conserved or lost in both the R. soongorica and sand rice genomes. Expression profiles of Arabidopsis orthologs further provided some clues to the function of the species-specific conserved PEDGs. Such orthologs included LEAFY PETIOLE, which could be a candidate gene involved in the development of branch priority in sand rice.

A psammophyte Agriophyllum squarrosum (L.) Moq.: a potential food crop

Agriophyllum squarrosum is an annual psammophyte adapted to mobile sand dunes in arid and semi-arid regions of Central Asia. The species has evolved a range of physiological, morphological, and ecological adaptations to allow it to be a pioneer species of unstable, nutrient-poor, drought-prone and hot sand dunes. Local populations in the sandy desert regions of China consume the seed of the species during periods of food shortage, and refer to the plant as “shami” in Chinese, which translates as “sand rice”. The sand rice seeds have high nutritional value, containing around 23 % protein, 9 % lipid, 45 % carbohydrates, 8 % crude fiber and 5 % ash. The protein fraction includes the full range of essential amino acids required in the human diet. The lipid fraction comprises mostly polyunsaturated fatty acid. The ash fraction is rich in iron. Sand rice is a good candidate species for domestication to provide a food crop resilient to future climate change.