Genome-wide analysis reveals four key transcription factors associated with cadmium stress in creeping bentgrass (Agrostis stolonifera L.)

Cadmium (Cd) toxicity seriously affects the growth and development of plants, so studies on uptake, translocation, and accumulation of Cd in plants are crucial for phytoremediation. However, the molecular mechanism of the plant response to Cd stress remains poorly understood. The main objective of this study was to reveal differentially expressed genes (DEGs) under lower (BT2_5) and higher (BT43) Cd concentration treatments in creeping bentgrass. A total of 463,184 unigenes were obtained from creeping bentgrass leaves using RNA sequencing technology. Observation of leaf tissue morphology showed that the higher Cd concentration damages leaf tissues. Four key transcription factor (TF) families, WRKY, bZIP, ERF, and MYB, are associated with Cd stress in creeping bentgrass. Our findings revealed that these four TFs play crucial roles during the creeping bentgrass response to Cd stress. This study is mainly focused on the molecular characteristics of DEGs under Cd stress using transcriptomic analysis in creeping bentgrass. These results provide novel insight into the regulatory mechanisms of respond to Cd stress and enrich information for phytoremediation

Overexpression of MsSAG113 gene promotes leaf senescence in alfalfa via participating in the hormone regulatory network

IntroductionAlfalfa (Medicago sativa) is a kind of high quality leguminous forage species, which was widely cultivated in the world. Leaf senescence is an essential process in plant development and life cycle. Here, we reported the isolation and functional analysis of an alfalfa SENESCENCE-ASSOCIATED GENE113 (MsSAG113), which belongs to the PP2C family and mainly plays a role in promoting plant senescence.MethodsIn the study, Agrobacterium-mediated, gene expression analysis, next generation sequencing, DNA pull-down, yeast single hybridization and transient expression were used to identify the function of MsSAG113 gene.ResultsThe MsSAG113 gene was isolated from alfalfa, and the transgenic plants were obtained by Agrobacterium-mediated method. Compared with the wildtype, transgenic plants showed premature senescence in leaves, especially when cultivated under dark conditions. Meanwhile, application of exogenous hormones ABA, SA, MeJA, obviously acclerated leaf senescence of transgenic plants. Furthermore, the detached leaves from transgenic plants turned yellow earlier with lower chlorophyll content. Transcriptome analysis identified a total of 1,392 differentially expressed genes (DEGs), involving 13 transcription factor families. Of which, 234 genes were related to phytohormone synthesis, metabolism and transduction. Pull-down assay and yeast one-hybrid assay confirmed that alfalfa zinc finger CCCH domain-containing protein 39 (MsC3H-39) could directly bind the upstream of MsSAG113 gene. In conclusion, the MsSAG113 gene plays a crucial role in promoting leaf senescence in alfalfa via participating in the hormone regulatory network.DiscussionThis provides an essential basis for further analysis on the regulatory network involving senescence-associated genes in alfalfa

Isolation and functional characterization of a Medicago sativa L. gene, MsLEA3-1

A full-length cDNA of 1,728 nt, called MsLEA3-1, was cloned from alfalfa by rapid amplification of cDNA ends from an expressed sequence tag homologous to soybean pGmPM10 (accession No. AAA91965.1). MsLEA3-1, encodes a deduced protein of 436 amino acids, a calculated molecular weight of 47.0 kDa, a theoretical isoelectric point of 5.18, and closest homology with late embryogenesis abundant proteins in soybean. Sequence homology suggested a signal peptide in the N terminus, and subcellular localization with GFP revealed that MsLEA3-1 was localized preferentially to the nucleolus. The transcript titre of MsLEA3-1 was strongly enriched in leaves compared with roots and stems of mature alfalfa plants. Gene expression of MsLEA3-1 was strongly induced when seedlings were treated with NaCl and ABA. Expression of the MsLEA3-1 transgenic was detected in transgenic tobacco. Malondialdehyde content and, electrical conductivity content were reduced and electrical conductivity and proline content were increased in transgenic tobacco compared with non-transgenic tobacco under salt stress. The results showed that accumulation of the MsLEA3-1 protein in the vegetative tissues of transgenic plants enhanced their tolerance to salt stress. These results demonstrate a role for the MsLEA3-1 protein in stress protection and suggest the potential of the MsLEA3-1 gene for genetic engineering of salt tolerance

Uncovering a Phenomenon of Active Hormone Transcriptional Regulation during Early Somatic Embryogenesis in Medicago sativa

Somatic embryogenesis (SE) is a developmental process in which somatic cells undergo dedifferentiation to become plant stem cells, and redifferentiation to become a whole embryo. SE is a prerequisite for molecular breeding and is an excellent platform to study cell development in the majority of plant species. However, the molecular mechanism involved in M. sativa somatic embryonic induction, embryonic and maturation is unclear. This study was designed to examine the differentially expressed genes (DEGs) and miRNA roles during somatic embryonic induction, embryonic and maturation. The cut cotyledon (ICE), non-embryogenic callus (NEC), embryogenic callus (EC) and cotyledon embryo (CE) were selected for transcriptome and small RNA sequencing. The results showed that 17,251 DEGs, and 177 known and 110 novel miRNAs families were involved in embryonic induction (ICE to NEC), embryonic (NEC to EC), and maturation (EC to CE). Expression patterns and functional classification analysis showed several novel genes and miRNAs involved in SE. Moreover, embryonic induction is an active process of molecular regulation, and hormonal signal transduction related to pathways involved in the whole SE. Finally, a miRNA–target interaction network was proposed during M. sativa SE. This study provides novel perspectives to comprehend the molecular mechanisms in M. sativa SE

Soil development in sand pits

It has not been paid enough attention to research of soil evolution in sand pit yet, so this study is focused on soil development in sand pit within primary succession. The study makes literary recherche of the most important factors which affect soil development. The study further detects volume of humus and soil pH in model area and how these attributes are changing in dependence on succession age. Differences of researches of pedogenesis in primary succession are discussed. Keywords: primary succession, sand pit, soi

Preparation and Electrochromic Properties of Benzodithiophene-Isoindigo Conjugated Polymers with Oligoethylene Glycol Side Chains

Functional polymers featuring good processability in non-halogenated, benzene-free green solvents are highly desired due to health and environmental concerns. Herein, a series of novel D-A type conjugated polymers, PBDT-IIDs, are designed and successfully prepared by “green” functionalization of the polymers with highly hydrophilic, highly polar, highly flexible, and biocompatible oligoethylene glycol (OEG) side chains in order to improve the processability. These series polymers are named PBDT-IID2, PBDT-IID3, and PBDT-IID4, respectively, according to the number of oxygen atoms in the side chain. After confirmation by structural characterization, the basic properties of PBDT-IIDs are also investigated. With the increase in the OEG side chain length, the polymer PBDT-IID4 not only has good solubility in the halogen solvent chlorobenzene, but also exhibits excellent solubility in the green halogen-free solvent methyltetrahydrofuran (Me-THF). As a result, the green solvent Me-THF can also be applied to prepare PBDT-IIDs’ electrochromic active layers, except for chlorobenzene and toluene. The electrochromism of PBDT IIDs under both positive and negative voltages has a practical application potential. The several controllable switches between dark green and khaki (0–0.6 V) are expected to show great potential in the field of military camouflage. Furthermore, according to the principle of red, green, and blue (RGB) mixing, light blue-green in the reduced state (−1.6 V) can be used in the preparation of complementary ECDs to provide one of the three primary colors (green)

The complete chloroplast genome of Medicago arabica (Fabaceae)

Medicago arabica (Linnaeus, 1762) Huds. is an important annual legume forage that grows in a wide range of climates, from subtropical to temperate. This study aimed to sequence the chloroplast genome of M. arabica and compare it with other legumes. In this study, we sequenced the entire chloroplast genome of M. arabica, which has 125,056 base pairs. The total GC content of the chloroplast genome of M. arabica was 34.4%. From the 110 unique genes of the circular genome, 30 tRNA genes, four rRNA genes, and 76 protein-coding genes were successfully annotated. A maximum likelihood (ML) tree was constructed using the model species and 17 species of the Medicago genus. M. arabica was shown to be phylogenetically closely related to M. polymorpha. The nucleotide diversity of the chloroplast genome may provide valuable molecular markers to study chloroplast, genetic breeding, and plant molecular evolution. These findings provide a solid foundation for future research on the molecular biology of the chloroplast

Global transcriptome analysis of alfalfa reveals six key biological processes of senescent leaves

Leaf senescence is a complex organized developmental stage limiting the yield of crop plants, and alfalfa is an important forage crop worldwide. However, our understanding of the molecular mechanism of leaf senescence and its influence on biomass in alfalfa is still limited. In this study, RNA sequencing was utilized to identify differentially expressed genes (DEGs) in young, mature, and senescent leaves, and the functions of key genes related to leaf senescence. A total of 163,511 transcripts and 77,901 unigenes were identified from the transcriptome, and 5,133 unigenes were differentially expressed. KEGG enrichment analyses revealed that ribosome and phenylpropanoid biosynthesis pathways, and starch and sucrose metabolism pathways are involved in leaf development and senescence in alfalfa. GO enrichment analyses exhibited that six clusters of DEGs are involved in leaf morphogenesis, leaf development, leaf formation, regulation of leaf development, leaf senescence and negative regulation of the leaf senescence biological process. The WRKY and NAC families of genes mainly consist of transcription factors that are involved in the leaf senescence process. Our results offer a novel interpretation of the molecular mechanisms of leaf senescence in alfalfa

Correction: De Novo Transcriptome Analysis for Kentucky Bluegrass Dwarf Mutants Induced by Space Mutation.

[This corrects the article DOI: 10.1371/journal.pone.0151768.]