The Stevia genus (Asteraceae) comprises around 230 species, distributed from the southern United States to the South American Andean region. Stevia rebaudiana , a Paraguayan herb that produces an intensely sweet diterpene glycoside called stevioside, is the most relevant member of this genus. Apart from S. rebaudiana , many other species belonging to the Stevia genus are considered medicinal and have been popularly used to treat different ailments. The members from this genus produce sesquiterpene lactones, diterpenes, longipinanes, and flavonoids as the main types of phytochemicals. Many pharmacological activities have been described for Stevia extracts and isolated compounds, antioxidant, antiparasitic, antiviral, anti-inflammatory, and antiproliferative activities being the most frequently mentioned. This review aims to present an update of the Stevia genus covering ethnobotanical aspects and traditional uses, phytochemistry, and biological activities of the extracts and isolated compounds.

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The Sawtooth Oak, Quercus acutissima Carruth., is an economically and ecologically important tree species in the family Fagaceae with a wide distribution in China. Here, we examined its intraspecific chloroplast (cp) genome variability using available and a newly sequenced genome. The new cp genome comes from a Q. acutissima individual collected from Shenyang (Northeast China; "Q. acutissima Shenyang" in the following), and then is compared with two recently published cp genomes from Tongchuan (Northwest China) and Nanjing (East China). The cp genome of Q. acutissima Shenyang exhibits a slightly larger genome size than the other two individuals, although each encodes 86 protein-coding genes, 40 tRNA genes and eight rRNA genes. We also found the length difference for the IR/SC boundary region among the three cp genomes. Sequence comparison revealed a high intraspecific genetic divergence: the three cp genomes differ by 332 sequence patterns including 77 single nucleotide polymorphisms, and 255 indels (each gap considered) scattering across 67 regions. Phylogenetic analyses based on the cp genome recovered the split between the subgenus Cerris and the subgenus Quercus, but revealed that three Q. acutissima individuals did not cluster together, indicating that even complete cp genome data fail to reproduce species boundaries in Asian members of section Cerris. Our results show that more complete plastomes covering remote ranges needs to be sequenced to provide a solid backbone for future population-scale in-depth studies and phylogenetic analysis of section Cerris.

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Jerusalem artichoke ( Helianthus tuberosus L.) is widely cultivated in Northwest China, and it has become an emerging economic crop that is rapidly developing. Because of its elevated inulin content and high resistance, it is widely used in functional food, inulin processing, feed, and ecological management. In this study, Illumina sequencing technology was utilized to assemble and annotate the complete chloroplast genome sequences of Jerusalem artichoke. The total length was 151,431 bp, including four conserved regions: A pair of reverse repeat regions (IRa 24,568 bp and IRb 24,603 bp), a large single-copy region (83,981 bp), and a small single-copy region (18,279 bp). The genome had a total of 115 genes, with 19 present in the reverse direction in the IR region. A total of 36 simple sequence repeats (SSRs) were identified in the coding and non-coding regions, most of which were biased toward A/T bases. A total of 32 SSRs were distributed in the non-coding regions. A comparative analysis of the chloroplast genome sequence of the Jerusalem artichoke and other species of the composite family revealed that the chloroplast genome sequences of plants of the composite family were highly conserved. Differences were observed in 24 gene loci in the coding region, with the degree of differentiation of the ycf2 gene being the most obvious. A phylogenetic analysis showed that H. petiolaris subsp. fallax had the closest relationship with Jerusalem artichoke, both members of the Helianthus genus. Selective locus detection of the ycf2 gene in eight species of the composite family was performed to explore adaptive evolution traits of the ycf2 gene in Jerusalem artichoke. The results show that there are significant and extremely significant positive selection sites at the 1239N and 1518R loci, respectively, indicating that the ycf2 gene has been subject to adaptive evolution. Insights from our assessment of the complete chloroplast genome sequences of Jerusalem artichoke will aid in the in-depth study of the evolutionary relationship of the composite family and provide significant sequencing information for the genetic improvement of Jerusalem artichoke.

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Oak pollen is a major respiratory allergen in Korea, and the distribution of oak trees is expected to increase by ecological succession and climate change. One of the drivers of climate change is increasing CO 2 , which is also known to amplify the allergy risk of weed pollen by inducing elevated allergenic protein content. However, the impact of CO 2 concentration on tree pollen is not clearly understood due to the experimental difficulties in carrying out extended CO 2 treatment. To study the response of pollen production of sawtooth oak trees (Quercus acutissima) to elevated levels of ambient CO 2 , three open-top chambers at the National Institute of Forest Science in Suwon, Korea were utilized with daytime (8 am-6 pm) CO 2 concentrations of ambient (× 1.0, ~ 400 ppm), × 1.4 (~ 560 ppm), and × 1.8 (~ 720 ppm) treatments. Each chamber had three sawtooth oak trees planted in September 2009. One or two trees per chamber matured to bloom in 2016. Five to six catkins were selected per tree and polyethylene bags were attached to collect pollen grains. The total number of catkins per tree was counted and the number and weight of pollen grains per catkin were measured. Oak allergen-Que a 1 (Allergon Co., Uppsala, Sweden)-was extracted and purified to make an ELISA kit by which the antigen levels in the pollen samples were quantified. Total pollen counts per tree of the × 1.4 and × 1.8 treatments showed significant increase of 353 and 1299%, respectively, from the × 1.0 treatment (p 2 levels, which are expected in the changing climate, produced significantly higher amount of pollen and allergenic protein than under the present air conditions.

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Effective population size ( N e ) is among the most important metrics in evolutionary biology. In natural populations, it is often difficult to collect adequate demographic data to calculate N e directly. Consequently, genetic methods to estimate N e have been developed. Two N e estimators based on sibship reconstruction using multilocus genotype data have been developed in recent years: sibship assignment and parentage analysis without parents. In this study, we evaluated the accuracy of sibship reconstruction using a large empirical dataset from five hatchery steelhead populations with known pedigrees and using 95 single nucleotide polymorphism (SNP) markers. We challenged the software COLONY with 2,599,961 known relationships and demonstrated that reconstruction of full-sib and unrelated pairs was greater than 95% and 99% accurate, respectively. However, reconstruction of half-sib pairs was poor ( N b ) when sample sizes were near or greater than the true N b and when assuming a monogamous mating system. We further demonstrated that both methods provide roughly equivalent estimates of N b . Our results indicate that sibship reconstruction and current SNP panels provide promise for estimating N b in steelhead populations in the region.

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