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Leaf color is one of the well-sought traits in breeding program for Anthurium andraeanum Lind. Knowledge of mechanisms in anthuriums to produce leaves with different shades of green would help to effectively select desirable traits. In this study, the micro- and ultra-structural and physiological features of leaves on wild type and leaf color mutants (dark green, rubescent, etiolated, albino) in A. andraeanum ‘Sonate’ were analyzed. Results show that chloroplasts of leaf color mutants exhibited abnormal morphology and distribution. Using next generation sequencing technology followed by de novo assembly, leaf transcriptomes comprising of 41,017 unigenes with an average sequence length of 768 bp were produced from wild type and rubescent mutant. From the 27,539 (67.1%) unigenes with annotated functions, 858 significantly differently expressed genes (DEGs) were identified, consisting of 446 up-regulated genes and 412 down-regulated genes. Genes that affect chloroplasts development and division, and chlorophyll biosynthesis were included in the down-regulated DEGs. Quantitative real-time PCR (qRT-PCR) analysis validated that the expression level of those genes was significantly lower in the rubescent, etiolated, and albino mutant compared to wild type plants, which concurs with the differences in micro- and ultra-structures and physiological features between these two types of plants. Conclusively, the leaf color formation is greatly affected by the activity of chloroplast development and pigment biosynthesis. And the possible formation pathway of leaf color mutant of A. andraeanum ‘Sonate’ is deduced based on our results.

cHere we completely sequenced four mcr-1-haboring plasmids, isolated from two extended-spectrum-␤-lactamase (ESBL)-producing Escherichia coli and two carbapenemase-producing Klebsiella pneumoniae clinical isolates. The mcr-1-harboring plasmids from an E. coli sequence type 2448 (ST2448) isolate and two K. pneumoniae ST25 isolates were identical (all pMCR1-IncX4), belonging to the IncX4 incompatibility group, while the plasmid from an E. coli ST2085 isolate (pMCR1-IncI2) belongs to the IncI2 group. A nearly identical 2.6-kb mcr-1-pap2 element was found to be shared by all mcr-1-carrying plasmids.T he plasmid-mediated colistin resistance gene, mcr-1, has recently been reported from animals and hospitalized patients in China (1). Since then, mcr-1 has been found in ϳ20 countries on four different continents (2). Alarmingly, mcr-1 has also been identified in several multidrug-resistant bacteria, including extended-spectrum-␤-lactamase (ESBL)-producing and carbapenemase-producing Enterobacteriaceae (CPE) (3-9). However, knowledge regarding the structure of mcr-1-harboring plasmids is limited. Here we completely sequenced four mcr-1-harboring plasmids (three of which are identical), isolated from two ESBLproducing Escherichia coli and two carbapenemase-producing Klebsiella pneumoniae clinical isolates (4).In a recent study, we identified mcr-1 in two ESBL-producing E. coli (SZ01 and SZ02) and two carbapenemase-producing K. pneumoniae (SZ03 and SZ04) clinical isolates from a tertiary hospital in eastern China (4). SZ01, SZ02, and SZ04 carry ESBL gene bla CTX-M-55 , while SZ03 and SZ04 harbor carbapenemase gene bla . Multilocus sequence typing (MLST) (10, 11) showed that the two E. coli isolates, SZ01 and SZ02, belong to two unrelated sequence types (STs) (ST2448 and ST2085), while the two K. pneumoniae strains (isolated from the same patient) both belong to ST25. The mcr-1-harboring plasmids from all four isolates were subsequently transferred to recipient strain E. coli J53 AZ r via conjugation, along with the bla NDM-5 -harboring plasmids from SZ03 and SZ04. Susceptibility testing revealed that the four mcr-1-harboring E. coli transconjugants were resistant to colistin but not to any of the other antimicrobial agents tested. The two bla transconjugants were resistant to all ␤-lactams, except for aztreonam, but remained susceptible to other classes of antimicrobial agents (data not shown). The mcr-1-and bla NDM-5 -harboring plasmids from these transconjugants were extracted and subjected to sequencing using the Illumina MiSeq platform (12). The sequencing reads were assembled de novo using SPAdes (13), and gaps were closed by standard PCR and Sanger sequencing as described previously (12).The mcr-1-harboring plasmids from SZ01, SZ03, and SZ04 (subsequently named pMCR1-IncX4) were all identical, belonging to the IncX4 incompatibility group, and were 33,287 bp in length with a GϩC content of 41.8%. The backbone of pMCR1-IncX4 is similar to that of other IncX4 plasmids, including pJIE143 (GenBank accession no. JN194214...

Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed.

In rice (Oryza sativa), amylose content (AC) is the major factor that determines eating and cooking quality (ECQ). The diversity in AC is largely attributed to natural allelic variation at the Waxy (Wx) locus. Here we identified a rare Wx allele, Wxmw, which combines a favorable AC, improved ECQ and grain transparency. Based on a phylogenetic analysis of Wx genomic sequences from 370 rice accessions, we speculated that Wxmw may have derived from recombination between two important natural Wx alleles, Wxin and Wxb. We validated the effects of Wxmw on rice grain quality using both transgenic lines and near‐isogenic lines (NILs). When introgressed into the japonica Nipponbare (NIP) background, Wxmw resulted in a moderate AC that was intermediate between that of NILs carrying the Wxb allele and NILs with the Wxmp allele. Notably, mature grains of NILs fixed for Wxmw had an improved transparent endosperm relative to soft rice. Further, we introduced Wxmw into a high‐yielding japonica cultivar via molecular marker‐assisted selection: the introgressed lines exhibited clear improvements in ECQ and endosperm transparency. Our results suggest that Wxmw is a promising allele to improve grain quality, especially ECQ and grain transparency of high‐yielding japonica cultivars, in rice breeding programs.

BackgroundFruits of persimmon plants are traditional healthy food in China, Korea and Japan. However, due to the shortage of morphological and DNA markers, the development of persimmon industry has been heavily inhibited.ResultsChloroplast genomes of Diospyros cathayensis, D. virginiana, D. rhombifolia and D. deyangensis were newly sequenced. Comparative analyses of ten chloroplast genomes including six previously published chloroplast genomes of Diospyros provided new insights into the genome sequence diversity and genomic resources of the genus. Eight hyper-variable regions, trnH-psbA, rps16-trnQ, rpoB-trnC, rps4-trnT-trnL, ndhF, ndhF-rpl32-trnL, ycf1a, and ycf1b, were discovered and can be used as chloroplast DNA markers at/above species levels. The complete chloroplast genome sequences provided the best resolution at inter-specific level in comparison with different chloroplast DNA sequence datasets.ConclusionDiospyros oleifera, D. deyangensis, D. virginiana, D. glaucifolia, D. lotus and D. jinzaoshi are important wild species closely related to the cultivated persimmon D. kaki. The hyper-variable regions can be used as DNA markers for global genetic diversity detection of Diospyros. Deeper study on these taxa would be helpful for elucidating the origin of D. kaki.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1421-3) contains supplementary material, which is available to authorized users.

In this report, self-sterility in Camellia oleifera was explored by comparing structural and statistical characteristics following self-pollination (SP) and cross-pollination (CP). Although slightly delayed pollen germination and pollen tube growth in selfed ovaries compared to crossed ovaries was observed, there was no significant difference in the percentages of pollen that germinated and pollen tubes that grew to the base of the style. There was also no difference in morphological structure after the two pollination treatments. However, the proportions of ovule penetration and double fertilization in selfed ovules were significantly lower than in crossed ovules, indicating that a prezygotic late-acting self-incompatible mechanism may exist in C. oleifera. Callose deposition was observed in selfed abortive ovules, but not in normal. Ovules did not show differences in anatomic structure during embryonic development, whereas significant differences were observed in the final fruit and seed set. In addition, aborted ovules in selfed ovaries occurred within 35 days after SP and prior to zygote division. However, this process did not occur continuously throughout the life cycle, and no zygotes were observed in the selfed abortive ovules. These results indicated that the self-sterility in C. oleifera may be caused by prezygotic late-acting self-incompatibility (LSI).

Streptomyces sp. linear plasmids and linear chromosomes usually contain conserved terminal palindromic sequences bound by the conserved telomeric proteins Tap and Tp, encoded by the tap and tpg genes, respectively, as well as plasmid loci required for DNA replication in circular mode when the telomeres are deleted. These consist of iterons and an adjacent rep gene. By using PCR, we found that 8 of 17 newly detected linear plasmids in Streptomyces strains lack typical telomeric tap and tpg sequences. Instead, two novel telomeres in plasmids pRL1 and pRL2 from the eight strains and one conserved telomere in pFRL1 from the other strains were identified, while multiple short palindromes were also found in the plasmids. The complete nucleotide sequence of pRL2 revealed a gene encoding a protein containing two domains, resembling Tap of Streptomyces and a helicase of Thiobacillus, and an adjacent gene encoding a protein similar to Tpg of Streptomyces and a portion of the telomere terminal protein pTP of adenoviruses. No typical iterons-rep loci were found in the three plasmids. These results indicate an unexpected diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids.Streptomyces species are gram-positive, high-GϩC, myceliumproducing eubacteria. Unlike the case for most eubacteria, linear plasmids and linear chromosomes are common in Streptomyces species (3,8,11,19,20,28). The linear plasmids vary in size between 12 kb (16) and 1,700 kb (19). Their telomeres contain long inverted repeat sequences of 44 bp (7) to 180 kb (21), and the 5Ј telomeric ends are linked covalently to terminal proteins (Tp) (1, 31). The telomeres of the ϳ8-Mb linear Streptomyces chromosomes are 46 bp to 1 Mb long (14,29). With the exceptions of the telomeres of the large linear plasmid SCP1 and the Streptomyces griseus linear chromosome (9, 18), Streptomyces linear plasmids and linear chromosomes usually contain conserved palindromic DNA sequences at their telomeres (13).Unlike the terminal protein-capped linear replicons of adenoviruses and bacteriophage ⌽29 (25), replication of Streptomyces linear plasmids starts at centrally located loci (27) and proceeds bidirectionally toward the telomeres (5). This leaves an ϳ280-nucleotide (nt) single-strand overhang at the 3Ј telomeric end of pSLA2 as a replication intermediate (5). To convert the 3Ј overhang to a double strand, the terminal 144 nt of the telomere contain short palindromes 1 to 5 (22), with palindromes 2/3 being bound by the conserved telomere-associated protein (Tap) to recruit the conserved telomere terminal protein (Tp) (1, 2).Streptomyces linear plasmids can also propagate in circular mode when the telomeres are deleted (5, 10, 24, 27). The centrally located locus for replication of pSLA2 consists of a rep-2 gene (encoding a DNA helicase) and its adjacent iterons within a transcribed rep-1 gene (6). The replication loci of plasmids SCP1 and pSLA2-L also consist of rep genes and different iteron sequences (10, 24). Such iterons-rep loci ...