Genet assignment and population structure analysis in a clonal forest-floor herb, Cardamine leucantha, using RAD-seq

The Role of Genetic Factors in the Differential Invasion Success of Two Spartina Species in China

Biological invasions have become one of the greatest threats to global biodiversity and ecosystem conservation. Most previous studies have revealed how successful invasive species adapt to new environments and climate change through phenotypic and genetic evolution. Some researchers suggested that understanding unsuccessful or less successful biological invasions might be important for understanding the relationships between invasion adaptability and climate factors. We compared the sexual reproduction ability, genetic diversity, and gene × environment interaction in two intentionally introduced alien species in China (Spartina anglica and Spartina alterniflora) based on restriction site-associated DNA (RAD) sequencing. After more than 50 years, the distribution of S. alterniflora has rapidly expanded, while S. anglica has experienced extreme dieback. A total of 212,939 single nucleotide polymorphisms (SNPs) for the two Spartina species were used for analysis. The multilocus genotype (MLG) analysis revealed that clonal reproduction was the prevalent mode of reproduction in both species, indicating that a change in the mode of reproduction was not the key factor enabling successful invasion by Spartina. All genetic diversity indicators (He, Ho, π) in S. alterniflora populations were at least two times higher than those in S. anglica populations, respectively (p < 0.001). Furthermore, the population genetic structure and stronger patterns of climate-associated loci provided support for rapid adaptive evolution in the populations of S. alterniflora in China. Altogether, our results highlight the importance of genetic diversity and local adaptation, which were driven by multiple source populations, in increasing the invasiveness of S. alterniflora.

Towards understanding the biological foundations of perenniality

Perennial life cycles enable plants to have remarkably long lifespans, as exemplified by trees that can live for thousands of years. For this, they require sophisticated regulatory networks that sense environmental changes and initiate adaptive responses in their growth patterns. Recent research has gradually elucidated fundamental mechanisms underlying the perennial life cycle. Intriguingly, several conserved components of the floral transition pathway in annuals such as Arabidopsis thaliana also participate in these regulatory mechanisms underpinning perenniality. Here, we provide an overview of perennials' physiological features and summarise their recently discovered molecular foundations. We also highlight the importance of deepening our understanding of perenniality in the development of perennial grain crops, which are promising elements of future sustainable agriculture.

Genomic population structure of sympatric sexual and asexual populations in a parasitic wasp, Meteorus pulchricornis (Hymenoptera: Braconidae), inferred from six hundred single-nucleotide polymorphism loci

In spite of the two-fold reproductive advantage, asexual reproduction is not common in nature, probably due to the associated genetic deterioration or reduced genetic variation. To understand how genetic diversity is maintained in existing asexual populations, we investigated the genetic diversity and population structure of sympatric sexual and asexual populations of a parasitic wasp, Meteorus pulchricornis, using 614 genome-wide single nucleotide polymorphisms. The genetic structures of the apomictic asexual populations were distinct, showing considerable genetic differentiation among them. Most of the asexual populations were highly differentiated from the sympatric sexual population; some asexual individuals could not be distinguished from members of the sexual population. Furthermore, significantly fewer multilocus genotypes were identified in the asexual populations (1-7) compared to the sexual population (42), which is consistent with their apomictic nature. The observed patterns of fixed heterozygous sites suggest that most asexual populations had the same evolutionary origin and have long since evolved individually; the detected gene flow between the sexual population and a few asexual population may indicate independent origins of asexuality. The potential role of occasional males in apomictic wasps is also discussed.

The Genetic Basis of Tomato Aroma

Tomato (Solanum lycopersicum L.) aroma is determined by the interaction of volatile compounds (VOCs) released by the tomato fruits with receptors in the nose, leading to a sensorial impression, such as "sweet", "smoky", or "fruity" aroma. Of the more than 400 VOCs released by tomato fruits, 21 have been reported as main contributors to the perceived tomato aroma. These VOCs can be grouped in five clusters, according to their biosynthetic origins. In the last decades, a vast array of scientific studies has investigated the genetic component of tomato aroma in modern tomato cultivars and their relatives. In this paper we aim to collect, compare, integrate and summarize the available literature on flavour-related QTLs in tomato. Three hundred and 5ifty nine (359) QTLs associated with tomato fruit VOCs were physically mapped on the genome and investigated for the presence of potential candidate genes. This review makes it possible to (i) pinpoint potential donors described in literature for specific traits, (ii) highlight important QTL regions by combining information from different populations, and (iii) pinpoint potential candidate genes. This overview aims to be a valuable resource for researchers aiming to elucidate the genetics underlying tomato flavour and for breeders who aim to improve tomato aroma.