No abstract

In this study, the mitochondrial genome of the stonefly, Oyamia nigribasis Banks, 1920 (Plecoptera: Perlidae), was sequenced and compared with the mtDNA genomes of 38 other stoneflies and two Ephemerae. The O. nigribasis mitogenome is a circular 15,923 bp molecule that encodes a large, noncoding control region (CR) and 37 typical mtDNA genes; these include 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs), respectively. Most of the PCGs initiated with ATN and terminated with TAN. The dihydrouridine (DHU) arm of tRNASer (AGN) was missing, whereas the other 21 tRNAs all exhibited the typical cloverleaf secondary structure. Stem-loop (SL) structures and tandem repeats were identified in the CR. Phylogenetic analyses using Bayesian inference and maximum likelihood were undertaken to determine relationships between stoneflies. Results indicated that the Antarctoperlaria, which contains Gripopterygidae, was absolutely separated from Arctoperlaria; this finding agrees with morphology. Finally, the overall relationships could be summarized as follows ((((Notonemouridae + Nemouridae) + Leuctridae) + (Scopuridae + (Capniidae + Taeniopterygidae))) + (((Perlodidae + Chloroperlidae) + Perlidae) + (Pteronarcyidae + (Peltoperlidae + Styloperlidae))) + ((Diamphipnoidae + Eustheniidae) + Gripopterygidae)).

Deterministic and stochastic forces both drive microbiota assembly in animals, yet their relative contribution remains elusive, especially in wild aquatic-insect-associated fungal communities. Here, we applied amplicon sequencing to survey the assembly mechanisms of the fungal community in 155 wild stonefly individuals involving 44 species of 20 genera within eight families collected from multiple locations in China. Analysis showed that fungal diversity and network complexity differed significantly among the eight stonefly families, and that the fungal communities in stoneflies exhibited a significant distance-decay pattern across large spatial scales. Both a structural equation model and variance partitioning analysis revealed that environmental factors (e.g., geographical, climatic) outweigh host attributes in shaping the fungal community of stoneflies. Using neutral and null model analyses, we also find that deterministic processes play a larger role than stochasticity in driving the fungal community assembly. However, the relative contribution of ecological processes including dispersal, drift, and selection, varied strongly with host taxonomy. Furthermore, environmental conditions also significantly affect the strength of these ecological processes. Overall, our findings illustrate that variations in host attributes and environment factors may moderate the relative influence of deterministic and stochastic processes to fungal community composition in wild stoneflies, which provides new insights into mechanisms of microbial community assembly in aquatic arthropods.

Mitochondrial genomes of three stoneflies, e.g., Claassenia magna Wu, 1948, Claassenia sp. 2 and Claassenia xucheni Chen, 2019 were sequenced in this study with 15,774, 15,777 and 15,746 bp in length, respectively. Each mitogenome contained 37 genes including 22 tRNAs, two ribosomal RNAs, 13 protein-coding genes (PCGs), and a noncoding control region (CR). In general, standard ATN start and TAN termination codons were evident in the PCGs. Although the dihydrouridine arm was absent in trnSer, the remaining 21 tRNAs displayed the characteristic cloverleaf secondary structure. Stem-loop structures were identified in the CRs of all three mitogenomes, but tandem repeats were only apparent in Claassenia xucheni. The mitogenomes of three Claassenia species were analyzed and compared with mitogenomes in 21 other stoneflies from the Perlidae and three Euholognatha species (Rhopalopsole bulbifera, Capnia zijinshana and Amphinemura longispina) as outgroups. Phylogenetic analyses using maximum likelihood and Bayesian inference. Phylogenetic analysis supported that Claassenia was recovered as the sister group of other Perlinae and Claassenia+Perlinae emerged from the paraphyletic Acroneuriinae. The final results supported that Claassenia was classified into subfamily Perlinae and proposed Claassenia represent a transitional group of the subfamilies Acroneuriinae and Perlinae. This study provided new molecular evidence for exploring the debatable taxonomic position of the genus Claassenia in Perlidae.

Tomato wilt disease caused by Fusarium oxysporum f. sp. 22 lycopersici (FOL) is a worldwide destructive disease of tomato. As exploring gene 23 expression and function approaches constitute an initial point for investigating 24 pathogen-host interaction, we performed RNA-seq and sRNA-seq analysis to 25 unravel regulated genes and miRNAs in tomato infected by FOL. Differentially 26 expressed (DE) protein coding gene and miRNA gene profiles upon inoculation 27 with FOL were presented at twenty-four hours post-inoculation including four 28 treatments. Total of more than 182.6 million and 132.2 million high quality clean 29 reads were obtained by RNA-seq and sRNA-seq, respectively. A large overlap was 30 found in DE mRNAs between susceptible cultivar Moneymaker and resistant 31 cultivar Motelle. All Gene Ontology terms were mainly classified into catalytic 32 activity, metabolic process and binding. Combining with qRT-PCR, five disease 33 resistance genes, Solyc01g095630, Solyc03g059080, Solyc00g174340, 34 Solyc11g071750 and Solyc05g050350, were verified to involved in the disease 35 resistance in the resistant cultivar Motelle treated with FOL. Northern blot analysis 36 further confirmed the results from sRNA-Seq and demonstrated that several 37 miRNAs including Sly-miR477-5p, sly-miR167a, novel_mir_675, novel_mir_504 38 and novel_mir_762 conferred FOL infection. Our data resulted that pathogen 39 resistant genes/miRNAs may play a critical role with the benefit of a coordinated 40 machinery in prompting the response in prompting FOL response in tomato, which 41 offered us with a future direction and surely help in generating models of mediated 42 resistance responses with assessment of genomic gene expression patterns. 43 KEYWARDS Tomato, Fusarium oxysporum f. sp. Lycopersici, Transcriptome, 44 Wilt disease, Resistance 45 46 100 2014). However, there was still no other reported miRNAs conferring tomato wilt 101 disease so far. In addition, there is far less attention to understand how genes and 102 miRNAs are integrated into the dynamic and complex regulatory network which 103 act together to regulate and result in the enhancement of resistance to FOL in 104 tomato. 105 The objective of this study was to determine differences between the transcript 106 profiles of susceptible Moneymaker and resistant Motelle tomato cultivars in 107 response to FOL infection and to reveal genes and miRNAs underlying the innate 108 immune response against the fungal pathogen combining RNA-seq and sRNA-seq 109 approach. In addition to genes predicted to response to pathogen infection, our 110 results also uncovered a bunch of novel fungal pathogen-responsive miRNAs in 111 tomato host plant for further functional characterization, and provided a broader 112 view of the dynamics of tomato defense triggered by FOL infection. 113 MATERIALS AND METHODS 114 Tomato materials and fungal culture 115 For tomato materials and fungal culture, susceptible cultivar Moneymaker (i-2/i-2) 116 and resistant cultivar Motelle (I-2/I-2) were applied for pl...