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Compared with other crops, pennycress (Thlaspi arvense L.) is a niche emerging oil crop. In recent years, research on pennycress has been increasingly reflected in various directions. Pennycress belongs to the Brassicaceae family and was introduced from Eurasia to North America. It has been found worldwide as a cultivated plant and weed. In this paper, we review the advantages of pennycress as a supplementary model plant of Arabidopsis thaliana, oil and protein extraction technology, seed composition analysis based on metabolomics, germplasm resource development, growth, and ecological impact research, abiotic stress, fatty acid extraction optimization strategy, and other aspects of studies over recent years. The main research directions proposed for the future are as follows: (1) assemble the genome of pennycress to complete its entire genome data, (2) optimize the extraction process of pennycress as biodiesel, (3) analyze the molecular mechanism of the fatty acid synthesis pathway in pennycress, and (4) the functions of key genes corresponding to various adversity conditions of pennycress. [ABSTRACT FROM AUTHOR]

The APETALA2/Ethylene Responsive Factor (AP2/ERF) gene family has been shown to play a crucial role in plant growth and development, stress responses and secondary metabolite biosynthesis. Nevertheless, little is known about the gene family in ginseng (Panax ginseng C.A. Meyer), an important medicinal herb in Asia and North America. Here, we report the systematic analysis of the gene family in ginseng using several transcriptomic databases. A total of 189 putative AP2/ERF genes, defined as PgERF001 through PgERF189, were identified and these PgERF genes were spliced into 397 transcripts. The 93 PgERF genes that have complete AP2 domains in open reading frame were classified into five subfamilies, DREB, ERF, AP2, RAV and Soloist. The DREB subfamily and ERF subfamily were further clustered into four and six groups, respectively, compared to the 12 groups of these subfamilies found in Arabidopsis thaliana. Gene ontology categorized these 397 transcripts of the 189 PgERF genes into eight functional subcategories, suggesting their functional differentiation, and they have been especially enriched for the subcategory of nucleic acid binding transcription factor activity. The expression activity and networks of the 397 PgERF transcripts have substantially diversified across tissues, developmental stages and genotypes. The expressions of the PgERF genes also significantly varied, when ginseng was subjected to cold stress, as tested using six PgERF genes, PgERF073, PgERF079, PgERF110, PgERF115, PgERF120 and PgERF128, randomly selected from the DREB subfamily. This result suggests that the DREB subfamily genes play an important role in plant response to cold stress. Finally, we studied the responses of the PgERF genes to methyl jasmonate (MeJA). We found that 288 (72.5%) of the 397 PgERF gene transcripts responded to the MeJA treatment, with 136 up-regulated and 152 down-regulated, indicating that most members of the PgERF gene family are responsive to MeJA. These results, therefore, provide new resources and knowledge necessary for family-wide functional analysis of the PgERF genes in ginseng and related species. [ABSTRACT FROM AUTHOR]

Summary: Fusarium head blight (FHB) is a disease of the floral tissues of wheat and barley for which highly resistant varieties are not available. Thus, there is a need to identify genes/mechanisms that can be targeted for the control of this devastating disease. Fusarium graminearum is the primary causal agent of FHB in North America. In addition, it also causes Fusarium seedling blight. Fusarium graminearum can also cause disease in the model plant Arabidopsis thaliana. The Arabidopsis–F. graminearum pathosystem has facilitated the identification of targets for the control of disease caused by this fungus. Here, we show that resistance against F. graminearum can be enhanced by flg22, a bacterial microbe‐associated molecular pattern (MAMP). flg22‐induced resistance in Arabidopsis requires its cognate pattern recognition receptor (PRR) FLS2, and is accompanied by the up‐regulation of WRKY29. The expression of WRKY29, which is associated with pattern‐triggered immunity (PTI), is also induced in response to F. graminearum infection. Furthermore, WRKY29 is required for basal resistance as well as flg22‐induced resistance to F. graminearum. Moreover, constitutive expression of WRKY29 in Arabidopsis enhances disease resistance. The PTI pathway is also activated in response to F. graminearum infection of wheat. Furthermore, flg22 application and ectopic expression of WRKY29 enhance FHB resistance in wheat. Thus, we conclude that the PTI pathway provides a target for the control of FHB in wheat. We further show that the ectopic expression of WRKY29 in wheat results in shorter stature and early heading time, traits that are important to wheat breeding. [ABSTRACT FROM AUTHOR]

The genera Boechera (A. Löve et D. Löve) and Arabidopsis , the latter containing the model plant Arabidopsis thaliana , belong to the same clade within the Brassicaceae family. Boechera is the only among the more than 370 genera in the Brassicaceae where apomixis is well documented. Apomixis refers to the asexual reproduction through seed, and a better understanding of the underlying mechanisms has great potential for applications in agriculture. The Boechera genus currently includes 110 species (of which 38 are reported to be triploid and thus apomictic), which are distributed mostly in the North America. The apomictic lineages of Boechera occur at both the diploid and triploid level and show signs of a hybridogenic origin, resulting in a modification of their chromosome structure, as reflected by alloploidy, aneuploidy, substitutions of homeologous chromosomes, and the presence of aberrant chromosomes. In this review, we discuss the advantages of the Boechera genus to study apomixis, consider its modes of reproduction as well as the inheritance and possible mechanisms controlling apomixis. We also consider population genetic aspects and a possible role of hybridization at the origin of apomixis in Boechera. The molecular tools available to study Boechera , such as transformation techniques, laser capture microdissection, analysis of transcriptomes etc. are also discussed. We survey available genome assemblies of Boechera spp. and point out the challenges to assemble the highly heterozygous genomes of apomictic species. Due to these challenges, we argue for the application of an alternative reference-free method for the comparative analysis of such genomes, provide an overview of genomic sequencing data in the genus Boechera suitable for such analysis, and provide examples of its application. [ABSTRACT FROM AUTHOR]

Lonicera maackii is an invasive Asian shrub naturalized in North America that has negative effects on forest understory vegetation. Aqueous extracts of leaves and roots of this plant have been shown to inhibit germination of several species. In this study, we examined the extent to which field-collected soils conditioned by L. maackii growth, with and without additions of L. maackii extracts, had effects on growth, morphology, and reproduction of Arabidopsis thaliana in a greenhouse setting. We also examined the effects of nutrient addition to the same soils on the performance of A. thaliana, whether plant responses to nutrients varied among L. maackii-conditioned and -unconditioned soils, and whether the effects of L. maackii extracts varied in soils with different histories and fertility. Plants grown in forest soil collected from a site where L. maackii was present grew slower and flowered later than plants grown in an unconditioned soil, but ended up being larger, with more leaves, branches and a higher total seed output. Nutrient addition had a positive effect on performance of A. thaliana, but when nutrients were added with extracts of L. maackii roots and leaves, the positive effects of nutrients were greatly diminished. Inhibiting plant responses to resource opportunities is a potentially important indirect effect of allelochemicals. Where direct effects of extracts on growth were seen, leaf extracts had a greater effect than root extracts. While the most important impacts of L. maackii in the field are undoubtedly due to competition for light and moisture, evidence for allelopathic effects of this plant is growing. [ABSTRACT FROM AUTHOR]

In addition to resource competition, allelopathy is believed to contribute to the invasiveness and impact of several plant invaders of North America. In this study, we examined whether aqueous leaf extracts of Alliaria petiolata and Lonicera maackii, two invaders of deciduous forests in North America, affected growth and reproduction of a target nonmycorrhizal plant and whether effects varied across a soil fertility gradient. While nutrient addition substantially improved the performance of Arabidopsis thaliana grown in field soils in pots in a growth room, addition of A. petiolata extracts to these soils had no significant independent or interactive effects on growth or reproduction. In contrast, addition of L. maackii extracts both directly reduced growth and reproduction of A. thaliana and greatly constrained increases in growth and reproduction of A. thaliana in response to increasing nutrient availability. Use of a nonmycorrhizal target plant revealed that effects of L. maackii were independent of allelopathic effects on mycorrhizae, an effect attributed to A. petiolata in other studies. [ABSTRACT FROM AUTHOR]

We investigated neutral genetic variation within and among 53 wild-collected populations of the weedy annual plant,Arabidopsis thaliana, in North America, using amplified fragment length polymorphism (AFLP) markers.A. thalianais thought to have been introduced to North America from Eurasia by humans; such an introduction might be expected to leave a clear geographical signal in the genetic data. To detect such patterns, we sampled populations at several hierarchical geographical levels. We collected individuals from populations in two areas of the Southeast and one in the Midwest, as well as individuals from populations in the Pacific Northwest and Northeast. To estimate within-population variation, we sampled eight individuals from each of six populations in the Southeast and Midwest. Among all 95 individuals analysed, we detected 131 polymorphic AFLP fragments. We found no evidence for continental or regional diversification. Individuals sampled from Midwestern and Southeastern populations intermingled in a neighbour-joining tree, and Mantel tests conducted within the Midwestern and Southeastern regions as well as the full data set failed to detect any significant relationship between geographical and genetic distance. These results mirror those found for most global surveys of neutral genetic variability inA. thaliana. Surprisingly, we detected substantial amounts of neutral genetic variability within populations. The levels of genetic variation within populations, coupled with the nongeographical nature of divergence among populations, are consistent with contemporary gene flow and point to a complex and dynamic population history ofA. thalianain North America. [ABSTRACT FROM AUTHOR]

Large-scale movement of organisms across their habitable range, or migration, is an important evolutionary process that can shape genetic diversity and influence the adaptive spread of alleles. Although human migrations have been studied in great detail with modern and ancient genomes, recent anthropogenic influence on reducing the biogeographical constraints on the migration of nonnative species has presented opportunities in several study systems to ask the questions about how repeated introductions shape genetic diversity in the introduced range. We present an extensive overview of population structure of North American Arabidopsis thaliana by studying a set of 500 whole-genome sequenced and over 2,800 RAD-seq genotyped individuals in the context of global diversity represented by Afro-Eurasian genomes. We use methods based on haplotype and rare-allele sharing as well as phylogenetic modeling to identify likely sources of introductions of extant N. American A. thaliana from the native range in Africa and Eurasia. We find evidence of admixture among the introduced lineages having increased haplotype diversity and reduced mutational load. We also detect signals of selection in immune-system-related genes that may impart qualitative disease resistance to pathogens of bacterial and oomycete origin. We conclude that multiple introductions to a nonnative range can rapidly enhance the adaptive potential of a colonizing species by increasing haplotypic diversity through admixture. Our results lay the foundation for further investigations into the functional significance of admixture., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)

This article presents science news briefs on topics featured in the issue. The majority of aerosol air pollution over North America likely originated in Asia. Plants such as Arabidopsis thaliana possess sequence polymorphisms, which allow it to delay flowering until winter has ended. Two compositionally similar planets have been discovered orbiting the same star with similar orbital periods, contrary to popular theories of planetary formation.