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Background The caper bush Capparis spinosa L. one of the most economically important species of Capparaceae, is a xerophytic shrub that is well adapted to drought and harsh environments. However, genetic studies on this species are limited because of the lack of its reference genome. Findings We sequenced and assembled the Capparis spinosa var. herbacea (Willd.) genome using data obtained from the combination of PacBio circular consensus sequencing and high-throughput chromosome conformation capture. The final genome assembly was approximately 274.53 Mb (contig N50 length of 9.36 Mb, scaffold N50 of 15.15 Mb), 99.23% of which was assigned to 21 chromosomes. In the whole-genome sequence, tandem repeats accounted for 19.28%, and transposable element sequences accounted for 43.98%. The proportion of tandem repeats in the C. spinosa var. herbacea genome was much higher than the average of 8.55% in plant genomes. A total of 21,577 protein-coding genes were predicted, with 98.82% being functionally annotated. The result of species divergence times showed that C. spinosa var. herbacea and Tarenaya hassleriana separated from a common ancestor 43.31 million years ago. Conclusions This study reported a high-quality reference genome assembly and genome features for the Capparaceae family. The assembled C. spinosa var. herbacea genome might provide a system for studying the diversity, speciation, and evolution of this family and serve as an important resource for understanding the mechanism of drought and high-temperature resistance. [ABSTRACT FROM AUTHOR]

Halophytes possess the capacity to uptake high levels of salt through physiological processes and their root architecture. Here, we investigated whether halophyte/non-halophyte intercropping in saline soil benefits plant growth and contains root-dialogue between interspecific species. Field and pot experiments were conducted to determine the plant biomasses and salt and nutrient distributions in three suaeda (Suaeda salsa)/maize (Zea mays L.) intercropping systems, set up by non-barrier, nylon-barrier, and plastic-barrier between plant roots. The suaeda/maize intercropping obviously transferred more Na+ to the suaeda root zone and decreased salt and Na+ contents. However, the biomass of the non-barrier-treated maize was significantly lower than that of the nylon and plastic barrier-treated maize. There was lower available N content in the soil of the non-barrier treated groups compared with the plastic barrier-treated groups. In addition, the pH was lower, and the available nutrient content was higher in the nylon barrier, which suggested that rhizospheric processes might occur between the two species. Therefore, we concluded that the suaeda/maize intercropping would be beneficial to the salt removal, but it caused an adverse effect for maize growth due to interspecific competition, and also revealed potential rhizospheric effects through the role of roots. This study provides an effective way for the improvement of saline land. [ABSTRACT FROM AUTHOR]

Background The halophyte Suaeda aralocaspica performs complete C4 photosynthesis within individual cells (SCC4), which is distinct from typical C4 plants, which require the collaboration of 2 types of photosynthetic cells. However, despite SCC4 plants having features that are valuable in engineering higher photosynthetic efficiencies in agriculturally important C3 species such as rice, there are no reported sequenced SCC4 plant genomes, limiting our understanding of the mechanisms involved in, and evolution of, SCC4 photosynthesis. Findings Using Illumina and Pacific Biosciences sequencing platforms, we generated ∼202 Gb of clean genomic DNA sequences having a 433-fold coverage based on the 467 Mb estimated genome size of S. aralocaspica. The final genome assembly was 452 Mb, consisting of 4,033 scaffolds, with a scaffold N50 length of 1.83 Mb. We annotated 29,604 protein-coding genes using Evidence Modeler based on the gene information from ab initio predictions, homology levels with known genes, and RNA sequencing–based transcriptome evidence. We also annotated noncoding genes, including 1,651 long noncoding RNAs, 21 microRNAs, 382 transfer RNAs, 88 small nuclear RNAs, and 325 ribosomal RNAs. A complete (circular with no gaps) chloroplast genome of S. aralocaspica 146,654 bp in length was also assembled. Conclusions We have presented the genome sequence of the SCC4 plant S. aralocaspica. Knowledge of the genome of S. aralocaspica should increase our understanding of the evolution of SCC4 photosynthesis and contribute to the engineering of C4 photosynthesis into economically important C3 crops. [ABSTRACT FROM AUTHOR]

Under the sufficient nitrogen supply, it is of great significance to investigate the law of biomass allocation, root morphological traits, and the salt absorption capacity of euhalophytes to evaluate their biological desalination in saline soil. Although the curvilinear responses of biomass accumulation and root morphology in response to soil salinity have been recognized, these perceptions are still confined to the descriptions of inter-treatment population changes and lack details on biomass allocation in organs at an individual level. In this study, Suaeda salsa was grown in root boxes across a range of soil salt levels. The study showed that their growth and development were significantly affected by soil soluble salts. The law of biomass allocation was described as follows: increased soil soluble salts significantly increased the leaf mass ratio and decreased the stem mass ratio, and slightly increased the root mass ratio among treatments. For individuals at each treatment, leaf mass ratio > stem mass ratio > root mass ratio, except in the control treatment at the flower bud and fruit stages. Biomass responses of the control treatment indicated that salt was not rigorously required for Suaeda salsa in the presence of an adequate nitrogen supply, as verified by the correlation between biomass, nitrogen, and soil soluble salt. Salt could significantly inhibit the growth of Suaeda salsa (P<0.01), whereas nitrogen could significantly promote its growth (P<0.01). Root morphology in response to soil soluble salts showed that salt acquisition by the root was highest at a salt level of 0.70%, which corresponds to light saline soil. Consequently, we conclude that phytodesalination by Suaeda salsa was optimal in the light saline soil, followed by moderate saline soil., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Guo, Tian, Zhao, Zhang and Mai.)