Accumulating evidences show that SPLs are crucial regulators of plant abiotic stress tolerance and the highly conserved module miR156/SPL appears to balance plant growth and stress responses. The halophyte Tamarix chinensis is highly resistant to salt tress. SPLs of T. chinensis (TcSPLs) and theirs roles in salt stress responses remain elusive. In this study, we conducted a systematic analysis of the TcSPLs gene family including 12 members belonging to 7 groups. The physicochemical properties and conserved motifs showed divergence among groups and similarity in each group. The microRNA response elements (MREs) are conserved in location and sequence, with the exception of first MRE within TcSPL5. The miR156-targeted SPLs are identified by dual-luciferase reporter assay of MRE-miR156 interaction. The digital expression gene profiles cluster suggested potential different functions of miR156-targeted SPLs vs non-targeted SPLs in response to salt stress. The expression patterns analysis of miR156-targeted SPLs with a reverse expression trend to TcmiR156 suggested 1 h (salt stress time) could be a critical time point of post-transcription regulation in salt stress responses. Our work demonstrated the post-transcription regulation of miR156-targeted TcSPLs and transcription regulation of non-targeted TcSPLs in salt stress responses, and would be helpful to expound the miR156/SPL-mediated molecular mechanisms underlying T. chinensis salt stress tolerance.

Background: Clematisspecies are attractive ornamental plants with a variety of flower colors and patterns. Heat stress is one of the main factors restricting the growth, development, and ornamental value ofClematis.Clematis lanuginosaandClematis crassifoliaare large-flowered and evergreenClematisspecies, respectively, that show different tolerance to heat stress. We compared and analyzed the transcriptome ofC. lanuginoseandC. crassifoliaunder heat stress to determine the regulatory mechanism(s) of resistance.Results: A total of 1720 and 6178 differentially expressed genes were identified fromC. lanuginoseandC. crassifolia, respectively. The photosynthesis and oxidation–reduction processes ofC. crassifoliawere more sensitive thanC. lanuginoseunder heat stress. Glycine/serine/threonine metabolism, glyoxylic metabolism, and thiamine metabolism were important pathways in response to heat stress inC. lanuginose, and flavonoid biosynthesis, phenylalanine metabolism, and arginine/proline metabolism were the key pathways inC. crassifolia. SixsHSPs (c176964_g1, c200771_g1, c204924_g1, c199407_g2, c201522_g2, c192936_g1),POD1(c200317_g1),POD3(c210145_g2),DREB2(c182557_g1), andHSFA2(c206233_g2) may be key genes in the response to heat stress inC. lanuginoseandC. crassifolia.Conclusions: We compared important metabolic pathways and differentially expressed genes in response to heat stress betweenC. lanuginoseandC. crassifolia. The results increase our understanding of the response mechanism and candidate genes ofClematisunder heat stress. These data may contribute to the development of newClematisvarieties with greater heat tolerance.

Clematis tientaiensis is an ornamental plant with beautiful flowers that belongs to the Ranunculaceae family. C. tientaiensis is endemic to Zhejiang Province in China. Five different colours of the C. tientaiensis flower have been observed, and to explore the reason for this flower colour variation, transcriptome and metabolome sequencing analyses were conducted in this study. The results indicate that 32 metabolites participate in anthocyanin biosynthesis, and that 24 metabolites were differentially accumulated among the five different flower colours. The transcriptome sequencing results enabled the identification of 13,559 differentially expressed genes. Further analysis indicated that cyanidin-3-O-galactosidea and cyanidin-3-O-sophoroside promote anthocyanin accumulation in the flowers of C. tientaiensis, whereas the pelargonidin-3-O-galactoside plays a negative role in anthocyanin synthesis. In addition, a combined transcriptome and metabolome analysis showed that the WDR2 gene plays an important regulatory role in anthocyanin biosynthesis. The results of this study provide a basis for further research into the biosynthesis and regulation of anthocyanins in C. tientaiensis flowers.

Gladiolus is an important ornamental plant that is one of the world’s four most-grown cut flowers. Gladiolus gandavensis has only been found in the Cangnan County (Zhejiang Province) of China, which is recorded in the “Botanical”. To explore the origin of G. gandavensis, chloroplast genome sequencing was conducted. The results indicated that a total of 151,654 bp of circular DNA was obtained. The chloroplast genome of G. gandavensis has a quadripartite structure (contains a large single-copy (LSC) region (81,547 bp), a small single-copy region (SSC) (17,895 bp), and two inverted repeats (IRs) (IRa and IRb, 52,212 bp)), similar to that of other species. In addition, a total of 84 protein-coding genes, 8 rRNA-encoding genes, and 38 tRNA-encoding genes were present in the chloroplast genome. To further study the structural characteristics of the chloroplast genome in G. gandavensis, a comparative analysis of eight species of the Iridaceae family was conducted, and the results revealed higher similarity in the IR regions than in the LSC and SSC regions. In addition, 265 simple sequence repeats (SSRs) were detected in this study. The results of the phylogenetic analysis indicated that the chloroplast genome of G. gandavensis has high homology with the Crocus cartwrightianus and Crocus sativus chloroplast genomes. Genetic analysis based on the rbcl sequence among 49 Gladiolus species showed that samples 42, 49, 50, and 54 had high homology with the three samples from China (64, 65, and 66), which might be caused by chance similarity in genotypes. These results suggest that G. gandavensis may have originated from South Africa.

Masson pine (Pinus massoniana) is a core industrial tree species that is used for afforestation in southern China. Previous studies have shown that Auxin Response Factors (ARFs) are involved in the growth and development of various species, but the function of ARFs in Masson pine is unclear. In this research, we cloned and identified Masson pine ARF6 cDNA (PmARF6). The results showed that PmARF6 encodes a protein of 681 amino acids that is highly expressed in female flowers. Subcellular analysis showed that the PmARF6 protein occurred predominantly in the nucleus and cytomembrane of Masson pine cells. Compared with wild-type (WT) Arabidopsis, transgenic Arabidopsis plants overexpressing PmARF6 had fewer rosette leaves, and their flower development was slower. These results suggest that overexpression of PmARF6 may inhibit the flower and leaf development of Masson pine and provide new insights into the underlying developmental mechanism.