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The development of high-throughput sequencing technology has made it possible to develop molecular markers such as EST-SSR from transcriptome sequences in non-model plants such as bulbous flowers. However, the EST-SSR markers that have been developed are weakly validated and low polymorphic due to the short read size and poor quality of the assembled sequences. This study therefore used the CandiSSR pipeline to identify 550 potential polymorphic SSR loci among 487 homologous unigenes based on the transcriptomic sequences of three varieties of colored calla lily, and 460 of these loci with appropriate flanking sequences were suitable for primer pairs design. A further validation with 200 randomly selected EST-SSRs demonstrated an increase of more than 30% and 100% in amplification validity and polymorphism, respectively, in comparison with our previous study. In addition, since most of the current varieties of colored calla lily are hybridized from a few species, which have low genetic diversity, we subsequently identified primary core germplasm for 160 colored calla lily accessions using the aforementioned 40 polymorphic EST-SSRs. It was concluded that the core germplasm containing 42 accessions derived from the M strategy incorporated into the software Power Core was the most representative of all 160 original germplasm, as evidenced by the preservation of 100% of the EST-SSR variation, with a higher level of genetic diversity and heterogeneity (Nei = 0.40, I = 0.66, PIC = 0.43). This study provides a practical example of polymorphism EST-SSR markers developed from multiple transcriptomes for non-model plants. A future breeding program for colored calla lily will also benefit from the core germplasm defined by those molecular markers.

The MIKCC-type gene family plays important roles in plant growth, development, and tolerance of biotic and abiotic stress, especially during floral organ differentiation. However, there have been no studies of MIKCC-type genes in rose, and functional differentiation of family members has not been explored. In this study, we identified 42 MIKCC-type genes in rose, classified the genes into 12 subfamilies, and constructed a phylogenetic tree. We performed expression analysis of these genes, and found that expression patterns correlated with the predicted subfamily, indicating that the features of MIKCC-type genes were broadly conserved during evolution. Collinear analysis of MIKCC genes among Rosaceae species confirmed the occurrence of whole genome duplications (WGD) and revealed some species-specific MIKCC genes. Transcriptome analysis showed that the expression of some MIKCC-type genes responded to low temperatures (4°C, 24 h) during flower organ differentiation. These conserved, duplicated, and novel expression patterns of MIKCC-type genes may have facilitated the adaptation of rose to various internal and external environmental changes. The results of this study provide a theoretical basis for future functional analysis of the MIKCC genes in rose and investigation of the evolutionary pattern of the MIKCC gene family in the Rosaceae genome.

Phylogenomic studies based on plastid genome have resolved recalcitrant relationships among various plants, yet the phylogeny of Dennstaedtiaceae at the level of family and genera remains unresolved due to conflicting plastid genes, limited molecular data and incomplete taxon sampling of previous studies. The present study generated 30 new plastid genomes of Dennstaedtiaceae (9 genera, 29 species), which were combined with 42 publicly available plastid genomes (including 24 families, 27 genera, 42 species) to explore the evolution of Dennstaedtiaceae. In order to minimize the impact of systematic errors on the resolution of phylogenetic inference, we applied six strategies to generate 30 datasets based on CDS, intergenic spacers, and whole plastome, and two tree inference methods (maximum-likelihood, ML; and multispecies coalescent, MSC) to comprehensively analyze the plastome-scale data. Besides, the phylogenetic signal among all loci was quantified for controversial nodes using ML framework, and different topologies hypotheses among all datasets were tested. The species trees based on different datasets and methods revealed obvious conflicts at the base of the polypody ferns. The topology of the “CDS-codon-align-rm3” (CDS with the removal of the third codon) matrix was selected as the primary reference or summary tree. The final phylogenetic tree supported Dennstaedtiaceae as the sister group to eupolypods, and Dennstaedtioideae was divided into four clades with full support. This robust reconstructed phylogenetic backbone establishes a framework for future studies on Dennstaedtiaceae classification, evolution and diversification. The present study suggests considering plastid phylogenomic conflict when using plastid genomes. From our results, reducing saturated genes or sites can effectively mitigate tree conflicts for distantly related taxa. Moreover, phylogenetic trees based on amino acid sequences can be used as a comparison to verify the confidence of nucleotide-based trees.

The MIKCC-type gene family plays important roles in plant growth, development, and tolerance of biotic and abiotic stress, especially during floral organ differentiation. However, there have been no studies of MIKCC-type genes in rose, and functional differentiation of family members has not been explored. In this study, we identified 42 MIKCC-type genes in rose, classified the genes into 12 subfamilies, and constructed a phylogenetic tree. We performed expression analysis of these genes, and found that expression patterns correlated with the predicted subfamily, indicating that the features of MIKCC-type genes were broadly conserved during evolution. Collinear analysis of MIKCC genes among Rosaceae species confirmed the occurrence of whole genome duplications (WGD) and revealed some species-specific MIKCC genes. Transcriptome analysis showed that the expression of some MIKCC-type genes responded to low temperatures (4°C, 24 h) during flower organ differentiation. These conserved, duplicated, and novel expression patterns of MIKCC-type genes may have facilitated the adaptation of rose to various internal and external environmental changes. The results of this study provide a theoretical basis for future functional analysis of the MIKCC genes in rose and investigation of the evolutionary pattern of the MIKCC gene family in the Rosaceae genome. [ABSTRACT FROM AUTHOR]