Salt stress severely inhibits crop growth and production. The native turfgrass species Carex rigescens in northern China, exhibits extraordinary tolerance to multiple abiotic stresses. However, little is known about its specific metabolites and pathways under salt stress. To explore the molecular metabolic mechanisms under salt stress, we conducted metabolome analysis combined with transcriptome analysis of two varieties of Carex rigescens with differing salt tolerances: salt-sensitive Lvping NO.1 and salt-tolerant Lvping NO.2. After 5 days of salt treatment, 114 and 131 differentially abundant metabolites (DAMs) were found in Lvping NO.1 and Lvping NO.2, respectively. Among them, six amino acids involved in the amino acid biosynthesis pathway, namely, valine, phenylalanine, isoleucine, tryptophan, threonine, and serine, were accumulated after treatment. Furthermore, most DAMs related to phenylalanine biosynthesis, metabolism, and phenylpropanoid biosynthesis increased under salt stress in both varieties. The expression profiles of metabolism-associated genes were consistent with the metabolic profiles. However, genes including HCT, β-glucosidases, and F5H, and metabolite 4-hydroxycinnamic acid, of the two varieties may account for the differences in salt tolerance. Our study provides new insights into the mechanisms underlying salt tolerance in Carex rigescens and reveals potential metabolites and genes to improve crop resilience to saline environments.

Lawns play a vital role in urban development, but the impact of sod production on soil properties has always been controversial. In this study, we examined the physical, chemical, and biological properties of sod production bases across different regions and years [including northern China (2.5, 3, 5, 6, 8, 10, 12 years), referred to as N-2.5, N-3, etc., and southern China (3, 10, 11, 14, 17 years), referred to as S-3, S-10, etc.], with tall fescue and Kentucky bluegrass planted in the north and bermudagrass or creeping bentgrass planted in the south. Sod production was found to increase soil bulk density while reducing porosity and field capacity, but these effects did not consistently intensify with longer production periods. Except for available phosphorus and available potassium, other soil nutrients (total carbon, total nitrogen, organic matter, alkali-hydrolyzable nitrogen, etc.) were either unaffected or increased at certain time points (S-11, S-14). Prolonged sod production (S-10, S-17) also boosted microbial content. In northern regions, organic matter and total nitrogen were the key factors influencing microbial community structure, whereas in southern regions, alkali-hydrolyzable nitrogen, electrical conductivity, available potassium, and organic matter were most influential. We also found that crop rotation, sand mulching, and deep plowing could enhance soil nutrient content and microbial activity in sod production.

Alfalfa is an important forage crop around the world. LncRNAs are considered to be a class of functional biomacromolecules, while little is known about lncRNAs in alfalfa. In this study, RNAs from different tissues of alfalfa were sequenced and anlyzed with full-length transcriptome sequencing technology, yielding the full-length transcripts dataset of alfalfa. Based on sequencing and public RNA-seq data, lncRNAs of alfalfa were predicted genome-wide by CPC2 and PLEK. The results showed most lncRNAs shared low sequence conservation with those in other plant species, part of which seems originate from plastid genome. We also identified 88563 lncRNAs, approximately 99.8% of total lncRNAs, with possibility of coding small ORFs using two prediction tools. Our research generated the biggest sequence set of alfalfa lncRNAs, and revealed some plastid originated lncRNAs with high sequence conservation.