Identification in silico and expression analysis of a β-1-4-endoglucanase and β-galactosidase genes related to ripening in guava fruit

Background Guava fruit softening is a crucial process during ripening and this process involves a number of enzymes that modifies the cell wall. Two of the enzymes that regulate this process are (a) the β-1, 4-endoglucanase 17 (BEG) which hydrolyze β-1, 4 bonds from cellulose and hemicellulose, and (b) β-galactosidase (BGA) that hydrolyzes pectin chains. Bioinformatics and expression analysis information on these genes is limited in guava fruit. Results A fragment of a β-1, 4-endoglucanase 17 (PgE17), and another of a β-galactosidase (PgGa1) were identified. These sequences have a similarity of more than 85% with those reported in the NCBI database. In the guava genome, one homologous sequence was found for PgE17 in Chr 4 and two homologous to PgGa1: one in Chr 3 and the other one in Chr 6. Putative protein PgE17 contains part of the glyco_hydro_9 domain. Putative protein PgGa1 has a part of the glyco_hydro_35 domain. Phylogenetic analysis of PgE17 and PgGa1 revealed that both are highly conserved inside the Myrtaceae family. In silico expression analysis showed that both PgE17 and PgGa1 work in a coordinated way with other cell wall modifier enzymes. Expression of these genes was found in all the guava samples analyzed. However, the highest expression was found in the fruit in the breaking and ripe states. Conclusions A β-1, 4-endoglucanase 17, and β-galactosidase 1 sequences were identified. PgE17 and PgGa1 are expressed in all the plant tissues, and fruit ripening states. Although, the highest expression was on breaker and ripe states.

Molecular Characterization of a Novel Virga-like Virus Isolated From Wheat

In this work, we report the isolation of a novel positive-sense single strand RNA virus from wheat, tentatively named Triticum aestivum-associated virga-like virus 1 (TaAVLV1). Further characterization revealed that the complete genome of TaAVLV1 was divided into two segments, RNA1 and RNA2, which were 3530 and 3466 nt long, excluding the polyA tail. These segments contained two open reading frames (ORFs). The ORF in RNA1 encoded an RNA-dependent RNA polymerase (RdRp), while the ORF in RNA2 encoded a putative protein carrying MET and HEL domains. Phylogenetic analysis based on the RdRp protein of each representative genus of Virgaviridae placed TaAVLV1 in the unclassified Virgaviridae clade of the Virgaviridae family. To our knowledge, this is the first report of virga-like virus isolated from wheat. Future studies will be conducted to examine its effect on host growth and development.

Complete genome sequence of a novel fusarivirus from the phytopathogenic fungus Corynespora cassiicola

Corynespora cassiicola is an important phytopathogenic fungus and it has severely impaired the production of crops. In this study, we report on the molecular characterization of a novel (+) ssRNA mycovirus, Corynespora cassiicola fusarivirus 1 (CcFV1) isolated from C. cassiicola strain 20200826-3-1. Excluding a poly (A) tail, the genome of the virus is 6491 nt containing three putative open reading frames. The large ORF1 encodes a polypeptide of 1524aa with a conserved RNA-dependent RNA polymerase (RdRp) domain, a helicase (Hel) domain, and a Phage-holin-3-6 (Phage-holin) domain. ORF2 encodes a polypeptide with a conserved Chromosome segregation ATPase (Smc) domain. The smallest ORF3 encodes a putative protein with an unknown function. Phylogenetic analysis based on the ORF1 and ORF2 of CcFV1 encoded polypeptide showed that CcFV1 is phylogenetically related to the newly proposed family Fusariviridae. Thus, we suggest that CcFV1 might be a novel member of the family Fusariviridae and is also the first discovered in C. cassiicola.

Complete Genome Analysis of a Novel Shewanella Phage vB_Sb_QDWS

We present here the results of the analysis of the complete genome sequence of a lytic bacteriophage, vB_Sb_QDWS, which is isolated from wastewater samples collected in Qingdao, China. The genome of phage vB_Sb_QDWS is composed of circular double-stranded DNA that is 47,902 bp in length with a G + C content of 63.16%. It has been predicted to contain 69 putative protein-coding genes. Phage morphology and bioinformatic analysis indicated that vB_Sb_QDWS is a novel phage of the family Siphoviridae.

Complete Mitochondrial and Plastid DNA Sequences of the Freshwater Green Microalga Medakamo hakoo

Here we report the complete organellar genome sequences of Medakamo hakoo, a green alga identified in freshwater in Japan. It has 90.8-kb plastid and 36.5-kb mitochondrial genomes containing 80 and 33 putative protein coding genes, respectively, representing the smallest organellar genome among currently known core Trebouxiophyceae.

CAT, AGTR2, L-SIGN and DC-SIGN are potential receptors for the entry of SARS-CoV-2 into human cells

Since December 2019, the COVID-19 caused by SARS-CoV-2 has been widely spread all over the world. It is reported that SARS-CoV-2 infection affects a series of human tissues, including lung, gastrointestinal tract, kidney, etc. ACE2 has been identified as the primary receptor of the SARS-CoV-2 Spike (S) protein. The relatively low expression level of this known receptor in the lungs, which is the predominantly infected organ in COVID-19, indicates that there may be some other co-receptors or alternative receptors of SARS-CoV-2 to work in coordination with ACE2. Here, we identified twenty-one candidate receptors of SARS-CoV-2, including ACE2-interactor proteins and SARS-CoV receptors. Then we investigated the protein expression levels of these twenty-one candidate receptors in different human tissues and found that five of which CAT, MME, L-SIGN, DC-SIGN, and AGTR2 were specifically expressed in SARS-CoV-2 affected tissues. Next, we performed molecular simulations of the above five candidate receptors with SARS-CoV-2 S protein, and found that the binding affinities of CAT, AGTR2, L-SIGN and DC-SIGN to S protein were even higher than ACE2. Interestingly, we also observed that CAT and AGTR2 bound to S protein in different regions with ACE2 conformationally, suggesting that these two proteins are likely capable of the co-receptors of ACE2. Conclusively, we considered that CAT, AGTR2, L-SIGN and DC-SIGN were the potential receptors of SARS-CoV-2. Moreover, AGTR2 and DC-SIGN tend to be highly expressed in the lungs of smokers, which is consistent with clinical phenomena of COVID-19, and further confirmed our conclusion. Besides, we also predicted the binding hot spots for these putative protein-protein interactions, which would help develop drugs against SARS-CoV-2.

Completion of Maize Stripe Virus Genome Sequence and Analysis of Diverse Isolates

Maize stripe virus is a pathogen of corn and sorghum in subtropical and tropical regions worldwide. We used high-throughput sequencing to obtain the complete nucleotide sequence for the reference genome of maize stripe virus and to sequence the genomes of ten additional isolates collected from the United States or Papua New Guinea. Genetically, maize stripe virus is most closely related to rice stripe virus. We completed and characterized the RNA1 sequence for maize stripe virus, which revealed a large open reading frame encoding a putative protein with ovarian tumor-like cysteine protease, endonuclease, and RNA-dependent RNA polymerase domains. Phylogenetic and amino acid identity analyses among geographically diverse isolates revealed evidence for reassortment in RNA3 that was correlated with the absence of RNA5. This study yielded a complete and updated genetic description of the tenuivirus maize stripe virus and provided insight into potential mechanisms underpinning its diversity.

Overexpression of OsMed16 Inhibits the Growth of Rice and Causes Spontaneous Cell Death

The Mediator complex transduces information from the DNA-bound transcription factors to the RNA polymerase II transcriptional machinery. Research on plant Mediator subunits has primarily been performed in Arabidopsis, while very few of them have been functionally characterized in rice. In this study, the rice Mediator subunit 16, OsMed16, was examined. OsMed16 encodes a putative protein of 1301 amino acids, which is longer than the version previously reported. It was expressed in various rice organs and localized to the nucleus. The knockout of OsMed16 resulted in rice seedling lethality. Its overexpression led to the retardation of rice growth, low yield, and spontaneous cell death in the leaf blade and sheath. RNA sequencing suggested that the overexpression of OsMed16 altered the expression of a large number of genes. Among them, the upregulation of some defense-related genes was verified. OsMed16 can regulate the expression of a wealth of genes, and alterations in its expression have a profound impact on plant growth, development, and defense responses in rice.

Heterogeneous Expression of Cymbidium longibracteatum Magnesium Protoporphyrin IX Methyltransferase (ClChlM) Activates Chlorophyll Biosynthesis in Transgenic Tobacco

Magnesium protoporphyrin IX methyltransferase (ChlM) plays an important role in the regulation of chlorophyll biosynthesis and chloroplast development. In the present study, we isolated a ChlM gene, designated ClChlM, from Cymbidium [Cymbidium longibracteatum (Wu & Chen) Chen & Liu]. The open reading frame (ORF) sequence of ClChlM was 945 bp and encoded a putative protein of 314 amino acids. The deduced ClChlM contained the conserved SAM/SAH binding pocket and substrate binding sites. Subcellular localization analysis of ClChlM revealed that the protein was localized in the chloroplast. Ectopic overexpression of ClChlM in tobacco (Nicotiana benthamiana Domin) increased ALA-synthesizing capacity and chlorophyll content and widely upregulated the expression level of photosynthesis-related genes, such as ClHemA, ClGSA, ClLhcb, ClCHLI, and ClCHLH. In conclusion, these results demonstrate that ClChlM plays a crucial role in the regulation of chlorophyll biosynthesis in C. longibracteatum and will help in breeding for leaf colour variance in the future. © 2021 Friends Science Publishers

Complete Genome Sequence of Stenotrophomonas maltophilia Siphophage Salva

ABSTRACT Stenotrophomonas maltophilia is a Gram-negative pathogen causing severe and often refractory illnesses such as pneumonia and bacteremia. We present the genome of phage Salva, a novel S. maltophilia phage that is not closely related to any phages currently deposited in GenBank. The genome is 60,789 bp, containing 102 putative protein-coding genes.