Combined analysis of microRNA and mRNA profiles provides insights into the pathogenic resistant mechanisms of the lotus rhizome rot.

Lotus rhizome rot caused by Fusarium oxysporum is a common vascular fungal disease in plants that significantly impacts the yield. However, only a few studies have studied the mechanism of Nelumbo nucifera responding to lotus rhizome rot. Here, we investigated the pathogenic genes and miRNAs in lotus rhizome rot to uncover the pathogenic resistant mechanisms by transcriptome and small RNA sequencing of lotus roots after inoculation with Fusarium oxysporum. GO and KEGG functional enrichment analysis showed that differential miRNAs were mostly enriched in starch and sucrose metabolism, biosynthesis of secondary metabolites, glutathione metabolism, brassinosteroid biosynthesis and flavonoid biosynthesis pathways. Twenty-seven upregulated miRNAs, 19 downregulated miRNAs and their target genes were identified. Correlation analysis found that miRNAs negatively regulate target genes, which were also enriched in starch and sucrose metabolism and glutathione metabolism pathways. Their expression was measured by reverse transcription quantitative PCR (qRT-PCR), and the results were consistent with the transcriptome analysis, thus verifying the reliability of transcriptome data. We selected three miRNAs (miRNA858-y, miRNA171-z and a novel miRNA novel-m0005-5p) to test the relationship between miRNAs and their target genes. The activity of the GUS testing assay indicated that miRNA could decrease the GUS activity by inhibiting the expression of their target genes. Collectively, this study provides a comprehensive analysis of transcriptome and small RNA sequencing of lotus root after inoculation with Fusarium oxysporum, and we identified candidate miRNAs and their target genes for breeding strategies of Nelumbo nucifera.

Identification of YABBY Transcription Factors and Their Function in ABA and Salinity Response in Nelumbo nucifera.

The plant-specific transcription factor family YABBY plays important roles in plant responses to biotic and abiotic stresses. Although the function of YABBY has been identified in many species, systematic analysis in lotus (Nelumbo nucifera) is still relatively lacking. The present study aimed to characterize all of the YABBY genes in lotus and obtain better insights into NnYABBYs in response to salt stress by depending on ABA signaling. Here, we identified nine YABBY genes by searching the whole lotus genome based on the conserved YABBY domain. Further analysis showed that these members were distributed on six different chromosomes and named from YABBY1 to YABBY9, which were divided into five subgroups, including YAB1, YAB2, YAB5, INO, and CRC. The analysis of cis-elements in promotors revealed that NnYABBYs could be involved in plant hormone signaling and plant responses to abiotic stresses. Quantitative real-time PCR (qRT-PCR) showed that NnYABBYs could be up-regulated or down-regulated by ABA, fluridone, and salt treatment. Subcellular localization indicated that NnYABBY4, NnYABBY5, and NnYABBY6 were mainly localized in the cell membrane and cytoplasm. In addition, the intrinsic trans-activity of NnYABBY was tested by a Y2H assay, which revealed that NnYABBY4, NnYABBY5, and NnYABBY6 are deprived of such a property. This study provided a theoretical basis and reference for the functional research of YABBY for the molecular breeding of lotus.

Genome-wide identification and characterization of laccase family members in eggplant (Solanum melongena L.).

Laccase, as a copper-containing polyphenol oxidase, primarily functions in the process of lignin, anthocyanin biosynthesis, and various abiotic/biotic stresses. In this study, forty-eight laccase members were identified in the eggplant genome. Only forty-two laccase genes from eggplant (SmLACs) were anchored unevenly in 12 chromosomes, the other six SmLACs were mapped on unanchored scaffolds. Phylogenetic analysis indicated that only twenty-five SmLACs were divided into six different groups on the basis of groups reported in Arabidopsis. Gene structure analysis revealed that the number of exons ranged from one to 13. Motif analysis revealed that SmLACs included six conserved motifs. In aspects of gene duplication analysis, twenty-one SmLACs were collinear with LAC genes from Arabidopsis, tomato or rice. Cis-regulatory elements analysis indicated many SmLACs may be involved in eggplant morphogenesis, flavonoid biosynthesis, diverse stresses and growth/development processes. Expression analysis further confirmed that a few SmLACs may function in vegetative and reproductive organs at different developmental stages and also in response to one or multiple stresses. This study would help to further understand and enrich the physiological function of the SmLAC gene family in eggplant, and may provide high-quality genetic resources for eggplant genetics and breeding.

A novel manganese oxidizing bacterium-Aeromonas hydrophila strain DS02: Mn(II) oxidization and biogenic Mn oxides generation.

The extensive applications of biogenic manganese oxides (BioMnOx) generated by manganese oxidizing bacteria (MOB) have attracted considerable attentions. In this study, we report on a novel MOB that has been isolated from sediments and identified as Aeromonas hydrophila strain DS02. The Mn(II) oxidation activity of strain DS02 under Mn(II) stress and the application of the associated BioMnOx products were investigated. Nearly 90.0% (495 mg L-1) of the soluble Mn(II) were removed and 45.6% (240 mg L-1) was converted to Mn(III/IV). Fitting the XPS data showed that Mn(IV)-oxide is the major component (82.0%) of the flake-shaped BioMnOx, corresponding to an average Mn oxidation number of 3.71. When the BioMnOx were coupled with the PMS activation, a 99.5% catalytic degradation of 2,4-dimethylaniline was observed after 80 min, revealing a high degradation efficiency.