More Like this

1. A graph-based genome and pan-genome variation of the model plant Setaria

   https://doi.org/10.1038/s41588-023-01423-w  

   He, Qiang; Tang, Sha; Zhi, Hui; Chen, Jinfeng; Zhang, Jun; Liang, Hongkai; Alam, Ornob; Li, Hongbo; Zhang, Hui; Xing, Lihe; et al (July 2023, Nature Genetics)

   Abstract Setaria italica(foxtail millet), a founder crop of East Asian agriculture, is a model plant for C4 photosynthesis and developing approaches to adaptive breeding across multiple climates. Here we established theSetariapan-genome by assembling 110 representative genomes from a worldwide collection. The pan-genome is composed of 73,528 gene families, of which 23.8%, 42.9%, 29.4% and 3.9% are core, soft core, dispensable and private genes, respectively; 202,884 nonredundant structural variants were also detected. The characterization of pan-genomic variants suggests their importance during foxtail millet domestication and improvement, as exemplified by the identification of the yield geneSiGW3, where a 366-bp presence/absence promoter variant accompanies gene expression variation. We developed a graph-based genome and performed large-scale genetic studies for 68 traits across 13 environments, identifying potential genes for millet improvement at different geographic sites. These can be used in marker-assisted breeding, genomic selection and genome editing to accelerate crop improvement under different climatic conditions. 

   more » « less
2. Form and contour: breeding and genetics of organ shape from wild relatives to modern vegetable crops

   https://doi.org/10.3389/fpls.2023.1257707  

   Goldman, Irwin L.; Wang, Yanbing; Alfaro, Andrey Vega; Brainard, Scott; Oravec, Madeline W.; McGregor, Cecilia Elizabeth; van der Knaap, Esther (September 2023, Frontiers in Plant Science)

   Shape is a primary determinant of consumer preference for many horticultural crops and it is also associated with many aspects of marketing, harvest mechanics, and postharvest handling. Perceptions of quality and preference often map to specific shapes of fruits, tubers, leaves, flowers, roots, and other plant organs. As a result, humans have greatly expanded the palette of shapes available for horticultural crops, in many cases creating a series of market classes where particular shapes predominate. Crop wild relatives possess organs shaped by natural selection, while domesticated species possess organs shaped by human desires. Selection for visually-pleasing shapes in vegetable crops resulted from a number of opportunistic factors, including modification of supernumerary cambia, allelic variation at loci that control fundamental processes such as cell division, cell elongation, transposon-mediated variation, and partitioning of photosynthate. Genes that control cell division patterning may be universal shape regulators in horticultural crops, influencing the form of fruits, tubers, and grains in disparate species. Crop wild relatives are often considered less relevant for modern breeding efforts when it comes to characteristics such as shape, however this view may be unnecessarily limiting. Useful allelic variation in wild species may not have been examined or exploited with respect to shape modifications, and newly emergent information on key genes and proteins may provide additional opportunities to regulate the form and contour of vegetable crops. 

   more » « less
3. Genomic analyses provide insights into peach local adaptation and responses to climate change

   https://doi.org/10.1101/gr.261032.120  

   Li, Yong; Cao, Ke; Li, Nan; Zhu, Gengrui; Fang, Weichao; Chen, Changwen; Wang, Xinwei; Guo, Jian; Wang, Qi; Ding, Tiyu; et al (April 2021, Genome Research)

   The environment has constantly shaped plant genomes, but the genetic bases underlying how plants adapt to environmental influences remain largely unknown. We constructed a high-density genomic variation map of 263 geographically representative peach landraces and wild relatives. A combination of whole-genome selection scans and genome-wide environmental association studies (GWEAS) was performed to reveal the genomic bases of peach adaptation to diverse climates. A total of 2092 selective sweeps that underlie local adaptation to both mild and extreme climates were identified, including 339 sweeps conferring genomic pattern of adaptation to high altitudes. Using genome-wide environmental association studies (GWEAS), a total of 2755 genomic loci strongly associated with 51 specific environmental variables were detected. The molecular mechanism underlying adaptive evolution of high drought, strong UVB, cold hardiness, sugar content, flesh color, and bloom date were revealed. Finally, based on 30 yr of observation, a candidate gene associated with bloom date advance, representing peach responses to global warming, was identified. Collectively, our study provides insights into molecular bases of how environments have shaped peach genomes by natural selection and adds candidate genes for future studies on evolutionary genetics, adaptation to climate changes, and breeding. 

   more » « less
4. Diverse Evolution in 111 Plant Genomes Reveals Purifying and Dosage Balancing Selection Models for F-Box Genes

   https://doi.org/10.3390/ijms22020871  

   Hua, Zhihua (January 2021, International Journal of Molecular Sciences)

   The F-box proteins function as substrate receptors to determine the specificity of Skp1-Cul1-F-box ubiquitin ligases. Genomic studies revealed large and diverse sizes of the F-box gene superfamily across plant species. Our previous studies suggested that the plant F-box gene superfamily is under genomic drift evolution promoted by epigenomic programming. However, how the size of the superfamily drifts across plant genomes is currently unknown. Through a large-scale genomic and phylogenetic comparison of the F-box gene superfamily covering 110 green plants and one red algal species, I discovered four distinct groups of plant F-box genes with diverse evolutionary processes. While the members in Clusters 1 and 2 are species/lineage-specific, those in Clusters 3 and 4 are present in over 46 plant genomes. Statistical modeling suggests that F-box genes from the former two groups are skewed toward fewer species and more paralogs compared to those of the latter two groups whose presence frequency and sizes in plant genomes follow a random statistical model. The enrichment of known Arabidopsis F-box genes in Clusters 3 and 4, along with comprehensive biochemical evidence showing that Arabidopsis members in Cluster 4 interact with the Arabidopsis Skp1-like 1 (ASK1), demonstrates over-representation of active F-box genes in these two groups. Collectively, I propose purifying and dosage balancing selection models to explain the lineage/species-specific duplications and expansions of F-box genes in plant genomes. The purifying selection model suggests that most, if not all, lineage/species-specific F-box genes are detrimental and are thus kept at low frequencies in plant genomes. 

   more » « less
5. Using Genomes and Evolutionary Analyses to Screen for Host-Specificity and Positive Selection in the Plant Pathogen Xylella fastidiosa

   https://doi.org/10.1128/aem.01220-22  

   Batarseh, Tiffany N.; Morales-Cruz, Abraham; Ingel, Brian; Roper, M. Caroline; Gaut, Brandon S. (September 2022, Applied and Environmental Microbiology)

   Alexandre, Gladys (Ed.)

   ABSTRACT Xylella fastidiosa infects several economically important crops in the Americas, and it also recently emerged in Europe. Here, using a set of Xylella genomes reflective of the genus-wide diversity, we performed a pan-genome analysis based on both core and accessory genes for two purposes: (i) to test associations between genetic divergence and plant host species and (ii) to identify positively selected genes that are potentially involved in arms-race dynamics. For the former, tests yielded significant evidence for the specialization of X. fastidiosa to plant host species. This observation contributes to a growing literature suggesting that the phylogenetic history of X. fastidiosa lineages affects the host range. For the latter, our analyses uncovered evidence of positive selection across codons for 5.3% (67 of 1,257) of the core genes and 5.4% (201 of 3,691) of the accessory genes. These genes are candidates to encode interacting factors with plant and insect hosts. Most of these genes had unknown functions, but we did identify some tractable candidates, including nagZ_2 , which encodes a beta-glucosidase that is important for Neisseria gonorrhoeae biofilm formation; cya , which modulates gene expression in pathogenic bacteria, and barA , a membrane associated histidine kinase that has roles in cell division, metabolism, and pili formation. IMPORTANCE Xylella fastidiosa causes devasting diseases to several critical crops. Because X. fastidiosa colonizes and infects many plant species, it is important to understand whether the genome of X. fastidiosa has genetic determinants that underlie specialization to specific host plants. We analyzed genome sequences of X. fastidiosa to investigate evolutionary relationships and to test for evidence of positive selection on specific genes. We found a significant signal between genome diversity and host plants, consistent with bacterial specialization to specific plant hosts. By screening for positive selection, we identified both core and accessory genes that may affect pathogenicity, including genes involved in biofilm formation. 

   more » « less