In higher plants, the shoot apical meristem produces lateral organs in a regular spacing (phyllotaxy) and timing (plastochron).  The molecular analysis of mutants associated with phyllotaxy and plastochron would increase our understanding of the mechanism of shoot architecture formation.  In this study, we identified mutant mnd8^ynp5 that shows an increased rate of leaf emergence and a larger number of nodes in combination with a dwarfed growth habit from an EMS-treated population of the elite barley cultivar Yangnongpi 5.  Using a map-based cloning strategy, the mnd8 gene was narrowed down to a 6.7-kb genomic interval on the long arm of chromosome 5H.  Sequence analysis revealed that a C to T single-nucleotide mutation occurred at the first exon (position 953) of HORVU5Hr1G118820, leading to an alanine (Ala) to valine (Val) substitution at the 318th amino acid site.  Next, HORVU5Hr1G118820 was defined as the candidate gene of MND8 encoding 514 amino acids and containing two multidrug and toxic compound extrusion (MATE) domains.  It is highly homologous to maize Bige1 and has a conserved function in the regulation of plant development by controlling the leaf initiation rate.  Examination of modern barely varieties showed that Hap-1 was the dominant haplotype and was selected in barley breeding around the world.  Collectively, our results indicated that mnd8^ynp5 is a novel allele of the HORVU5Hr1G118820 gene that is possibly responsible for the shortened plastochron and many noded dwarf phenotype in barley.

The pre-mRNA processing factor Prp6 is an essential component of the U4/U6.U5 tri-small nuclear ribonucleoprotein (snRNP).  In a previous study, mutations were identified in the PRP6 ortholog in four suppressors of Fgprp4 that was deleted of the only kinase FgPrp4 among the spliceosome components in the plant pathogenic fungus Fusarium graminearum.  In this study, we identified additional suppressor mutations in FgPrp6 and determined the suppressive effects of selected mutations.  In total, 12 mutations of FgPRP6 were identified in 20 suppressors of Fgprp4 by sequencing analysis.  Whereas three mutation sites are in the linker region of FgPrp6, seven are in the first two HAT repeats.  RNA-seq analysis showed that suppressor mutations on different sites caused different splicing efficiency recovery.  The suppressive effects of E308K and R230H were verified.  Similar to human and fission yeast, the FgPrp6 was phosphorylated by the FgPrp4 kinase.  Interestingly, the conserved Prp4-phosphorylation sites T261, T219&T221, and predicted phosphorylation sites T199&T200 on FgPrp6 were dispensable for the function of FgPrp6 in hyphal growth and sexual reproduction but important in plant infection.  They are required for the infectious growth of F. graminearum in wheat lemma.  RNA-seq analysis of the wheat lemma infected with Fgprp6/FgPRP6^Δ199–221-GFP or Fgprp6/FgPRP6^Δ250–262-GFP showed that 28 and 35% introns had splicing defects, respectively, which may be responsible for their defects in plant infection.    

Plant parasitic nematodes secrete effector proteins to parasitize hosts successfully.  Of these proteins, serine carboxypeptidases have critical roles in pathogenicity.  This study investigated the role of new effector AbSCP1 in Aphelenchoides besseyi pathogenicity.  In situ hybridization and qRT-PCR analyses indicated that AbSCP1 was exclusively expressed in the esophageal glands and upregulated in juveniles.  Subcellular localization assays indicated that the protein was expressed in the nucleus.  The ability to hydrolyze C-terminal amino acid residues was proven for AbSCP1.  Moreover, RNAi significantly reduced the expression of AbSCP1 and RNAi-treated nematodes’ reproductive potential.  Pathogenicity assays on rice showed that RNAi-treated nematodes were less pathogenic than the untreated control groups.  These results suggest the important role of AbSCP1 in the A. besseyi infection process.

Ten populations of Radopholus similis from different ornamental hosts were tested for their parasitism and pathogenicity to water spinach (Ipomoea aquatic), malabar spinach (Basella rubra), and squash (Cucurbita moschata) in pots. The results showed all three plants were new hosts of R. similis. Growth parameters of plants inoculated with nematodes were significantly lower than those of healthy control plants. All R. similis populations were pathogenic to the three plants, but pathogenicity differed among populations from different hosts. The same R. similis populations also showed different pathogenic effects in the three different plants. RadN5 population from Anthurium andraeanum had the highest pathogenicity to the three studied plants. RadN1 from A. andraeanum had the lowest pathogenicity to squash and RadN7 from Chrysalidocarpus lutesens had the lowest pathogenicity to water spinach and malabar spinach. R. similis is usually associated with root tissues, but here we report that it could be found to move and feed in the stem bases of all three studied plants. Sequence and phylogenetic analyses of DNA markers of the 18S rRNA, 28S rRNA, ITS rRNA, and mitochondrial DNA gene sequences of ten R. similis populations revealed significant genetic diversity. RadN5 and RadN6 populations from anthurium showed a close genetic relationship and could be distinguished from other populations by PCR-RFLP. At the same time, RadN5 and RadN6 populations were the most pathogenic to three studied plants. These results confirm the existence of large biological variability and molecular diversity among R. similis populations from the same or different hosts, and these characteristics are related to pathogenic variability.

In order to establish double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal antibody against the E protein of flavivirus strain JS804 in geese were used as the capture antibody and detection antibody, respectively. The optimal dilution of the capture antibody and detecting antibody capable of detecting the flavivirus strain JS804 in geese were 1:3 200 and 1:160 in the check-board titration, respectively. The reaction time of sample was 1 h, and the optimal working dilution of HRP-labeled goat-anti-mouse IgG was 1:10 000. The positive standard value was 0.247 (OD450 nm). The geese flavivirus could be detected at a minimal concentration of 1.875 μg mL-1. The ELISA had no cross-reaction with Newcastle disease virus (NDV), Avian influenza virus (AIV), Infectious bronchitis virus (IBV), Infectious bursal disease virus (IBDV), Duck hepatitis virus (DHV), and Gosling plague virus (GPV). Twenty clinical samples were detected by the DAS-ELISA and RT-PCR respectively, with the agreement rate of 75%. The results revealed that the DAS-ELISA possessed favorable specificity and higher sensitivity, indicating a suitable method for rapid detection of the duck or goose flavivirus.

Insecticidal activities of the petroleum ether-, chloroform-, ethyl acetate-, and water-soluble fractions of the methanolicextract of Ficus sarmentosa var. henryi were assayed against Musca domestica adults. The chloroform- and ethyl acetatesolublefractions were the most active with 92.6 and 88.9% mortalities (24 h after treatment) respectively. Therefore, thetwo fractions were combined and four compounds, isolated from the fractions by activity-guided fractionation, wereelucidated as 7-hydroxycoumarin, apigenin, eriodictyol, and quercetin by spectroscopic method and displayed excellentinsecticidal activities against adults of M. domestica and 4th instar larva of Aedes albopictus. Among those, 7-hydroxycoumarin showed the strongest insecticidal activities with lethal concentrations (LC50) values of 72.13 μg g-1sugar and 4.87 μg mL-1 (48 h after treatment) against the test insects respectively. The cytoxicities of these compounds onBTI-Tn-5B1-4 cell were also investigated for the insecticidal mechanism and found that quercetin represented superiorinhibitory activity with MTT assay and reactive oxygen species (ROS) against BTI-Tn-5B1-4 cell, but slightly weaker thanthat of the positive control (azadirachtin) and significantly greater than the negative control (DMSO only). Meanwhile,eriodictyol demonstrated the strongest effect on the mitochondrial membrane potentials (MMP). In conclusion, based ontheir comparative toxicities to commercial insecticides and their cytotoxic effects, some of the compounds from theF. sarmentosa have potential as botanical insecticides.