Background: Artemisia subg. Seriphidium, one of the most species-diverse groups within Artemisia, grows mainly in arid or semi-arid regions in temperate climates. Some members have considerable medicinal, ecological, and economic value. Previous studies on this subgenus have been limited by a dearth of genetic information and inadequate sampling, hampering our understanding of their phylogenetics and evolutionary history. We therefore sequenced and compared the chloroplast genomes of this subgenus, and evaluated their phylogenetic relationships. Results: We newly sequenced 18 chloroplast genomes of 16 subg. Seriphidium species and compared them with one previously published taxon. The chloroplast genomes, at 150,586–151,256 bp in length, comprised 133 genes, including 87 protein-coding genes, 37 tRNA genes, 8 rRNA genes, and one pseudogene, with GC content of 37.40–37.46%. Comparative analysis showed that genomic structures and gene order were relatively conserved, with only some variation in IR borders. A total of 2203 repeats (1385 SSRs and 818 LDRs) and 8 highly variable loci (trnK – rps16, trnE – ropB, trnT, ndhC – trnV, ndhF, rpl32 – trnL, ndhG – ndhI and ycf1) were detected in subg. Seriphidium chloroplast genomes. Phylogenetic analysis of the whole chloroplast genomes based on maximum likelihood and Bayesian inference analyses resolved subg. Seriphidium as polyphyletic, and segregated into two main clades, with the monospecific sect. Minchunensa embedded within sect. Seriphidium, suggesting that the whole chloroplast genomes can be used as molecular markers to infer the interspecific relationship of subg. Seriphidium taxa. Conclusion: Our findings reveal inconsistencies between the molecular phylogeny and traditional taxonomy of the subg. Seriphidium and provide new insights into the evolutionary development of this complex taxon. Meanwhile, the whole chloroplast genomes with sufficiently polymorphic can be used as superbarcodes to resolve interspecific relationships in subg. Seriphidium.

Land degradation caused by soil salinization and wind erosion is the major obstruction to sustainable agriculture in the arid region. Salsola species have the potential to prevent land degradation. However, there is limited information about seed germination requirements and tolerance to salinity and drought for representative Salsola species. This study aimed to assess the effects of the winged perianth (seed structural features) and abiotic factors (light, temperature, salinity, and drought) on the seed germination of these species. These Salsola species varied considerably in seed germination characteristics. Compared with naked seeds, winged seeds had lower germination percentages for S. heptapotamica S. rosacea, and S. nitraria species. Darkness decreased the germination percentage of winged and naked seeds of S. rosacea, however, for S. heptapotamica and S. nitraria, decreased seed germination was only when the winged perianth existed. Germination of S. heptapotamica, S. rosacea, and S. nitraria seeds depended on the perianth and light conditions. The naked seeds of these three species could germinate at a wide range of temperatures, especially in light. The presence of perianth, light, and temperature did not significantly influence the germination of S. ruthenica seeds. When cultivating these species, it is beneficial to remove the winged perianth of seeds and sow it on the soil surface when the temperature is above 5/15°C. In addition, seed germination of Salsola displayed high tolerance to salinity and drought. Compared with winged seeds, naked seeds showed lower recovery germination under high salinity but had a similar recovery of germination under high PEG concentration. Our study provides detailed germination information for the cultivation of these four representative Salsola species in degraded saline soils of the arid zone.

Background: Baolia H.W.Kung & G.L.Chu is a monotypic genus only known in Diebu County, Gansu Province, China. Its systematic position is contradictory, and its morphoanatomical characters deviate from all other Chenopodiaceae. Recent study has regarded Baolia as a sister group to Corispermoideae. We therefore sequenced and compared the chloroplast genomes of this species, and resolved its phylogenetic position based on both chloroplast genomes and marker sequences. Results: We sequenced 18 chloroplast genomes of 16 samples from two populations of Baolia bracteata and two Corispermum species. These genomes of Baolia ranged in size from 152,499 to 152,508 bp. Simple sequence repeats (SSRs) were primarily located in the LSC region of Baolia chloroplast genomes, and most of them consisted of single nucleotide A/T repeat sequences. Notably, there were differences in the types and numbers of SSRs between the two populations of B. bracteata. Our phylogenetic analysis, based on both complete chloroplast genomes from 33 species and a combination of three markers (ITS, rbcL, and matK) from 91 species, revealed that Baolia and Corispermoideae (Agriophyllum, Anthochlamys, and Corispermum) form a well-supported clade and sister to Acroglochin. According to our molecular dating results, a major divergence event between Acroglochin, Baolia, and Corispermeae occurred during the Middle Eocene, approximately 44.49 mya. Ancestral state reconstruction analysis showed that Baolia exhibited symplesiomorphies with those found in core Corispermoideae characteristics including pericarp and seed coat. Conclusions: Comparing the chloroplast genomes of B. bracteata with those of eleven typical Chenopodioideae and Corispermoideae species, we observed a high overall similarity and a one notable noteworthy case of inversion of approximately 3,100 bp. of DNA segments only in two Atriplex and four Chenopodium species. We suggest that Corispermoideae should be considered in a broader sense, it includes Corispermeae (core Corispermoideae: Agriophyllum, Anthochlamys, and Corispermum), as well as two new monotypic tribes, Acroglochineae (Acroglochin) and Baolieae (Baolia).

The NADP-malic enzyme (NADP-ME) catalyzes the reversible decarboxylation of L-malate to produce pyruvate, CO₂, and NADPH in the presence of a bivalent cation. In addition, this enzyme plays crucial roles in plant developmental and environment responses, especially for the plastidic isoform. However, this isoform is less studied in C₃–C₄ intermediate species under drought and salt stresses than in C₃ and C₄ species. In the present study, we characterized SaNADP-ME4 from the intermediate woody desert species Salsola laricifolia. SaNADP-ME4 encoded a protein of 646 amino acids, which was found to be located in the chloroplasts based on confocal imaging. Quantitative real-time PCR analysis showed that SaNADP-ME4 was highly expressed in leaves, followed by stems and roots, and SaNADP-ME4 expression was improved and reached its maximum under the 200 mm mannitol and 100 mm NaCl treatments, respectively. Arabidopsis overexpressing SaNADP-ME4 showed increased root length and fresh weight under mannitol and salt stress conditions at the seedling stage. In the adult stage, SaNADP-ME4 could alleviate the decreased in chlorophyll contents and PSII photochemical efficiency, as well as improve the expression of superoxide dismutase, peroxidase, and pyrroline-5-carboxylate synthase genes to enhance reactive oxygen species scavenging capability and proline levels. Our results suggest that SaNADP-ME4 overexpression in Arabidopsis increases drought and salt stress resistance.

Bassia scoparia is a widespread weedy species in the temperate regions of the world and is valued as a medicinal and ornamental plant. To date, the taxonomic concept of B. scoparia remains insufficiently studied due to a limited number of samples used in the previous phylogenetic analyses. To solve the taxonomy of the B. scoparia complex, we constructed a new phylogeny based on the nuclear ribosomal internal transcribed spacer (ITS), plastid intergenic spacer atpB-rbcL, and plastid region rpL16 intron sequences for numerous samples with diverse morphology. Our analysis revealed a close proximity and intermixed positions of the samples of the B. scoparia group with various morphology. Because of this polyphyly, we prefer to broadly delimit the species. An updated nomenclature of B. scoparia is provided including four new synonyms: Bassia angustifolia, B. littorea, Kochia albovillosa, and K. scoparia subsp. hirsutissima. In its new circumscription, B. scoparia encompasses populations with glabrous or variously hairy leaves and perianths. The original material of Kochia sieversiana, previously considered a species with hairy leaves and inflorescences, has the same diagnostic characters as in B. scoparia s.str. The correct name for more hairy-leaved plants is B. scoparia var. subvillosa. Plants with hairy perianths known as Kochia albovillosa and K. scoparia subsp. hirsutissima have a restricted distribution in Central Asia and South Siberia and have never been recorded as alien in other regions; they can be classified as a separate variety, B. scoparia var. hirsutissima. The ornamental variant of oblong or pyramidal shape may be called B. scoparia var. trichophila. Bassia scoparia is often confused with a similarly looking relative, B. indica, especially in North Africa, a region where secondary ranges of both species overlap. Phylogenetically, these species are sister groups; they share some morphological characters but have different primary distribution ranges. We traced a recent expansion of B. indica in the Mediterranean with the first record reported from the European continent (Spain) and uncovered various introduction pathways of the species in this region.