Silencing of <Emphasis Type="Italic">GbANS</Emphasis> reduces cotton resistance to <Emphasis Type="Italic">Verticillium dahliae</Emphasis> through decreased ROS scavenging during the pathogen invasion process

Anthocyanins are secondary metabolites that play important roles in plant adaption to adverse environments. The anthocyanin biosynthetic pathway is conserved in high plants. Previous studies revealed the significant role of anthocyanins in natural-colorized cotton. However, little is known about the involvement of anthocyanins in the interaction of cotton and pathogen. In this study, a pathogen-induced gene was isolated from Gossypium barbadense that encodes an anthocyanidin synthase protein (GbANS) with dioxygenase structures. GbANS was preferentially expressed in colored tissue. Silencing of GbANS significantly reduced the production of anthocyanins, as well as the cotton’s resistance to Verticillium dahliae. Biochemical studies revealed that GbANS-silenced cotton accumulated more hydrogen peroxide compared to control plants during the V. dahliae invasion process. This accumulation of hydrogen peroxide corresponded with increased cell death around the invasion sites, which in turn accelerated the V. dahliae infection. Taken together, we found that GbANS contributes to the biosynthesis of anthocyanins in cotton and anthocyanins positively regulate cotton’s resistance to V. dahliae.     

Regulation of stomatal movement by cortical microtubule organization in response to darkness and ABA signaling in <Emphasis Type="Italic">Arabidopsis</Emphasis>

Microtubule dynamics are essential for plant cell development and in producing responses to external stimuli. However, little is known about the regulation of microtubule dynamics or crosstalk between microtubule and stomatal movement. Here we identified microtubule reorganization as a crucial factor determining guard cell responses to dark and abscisic acid (ABA) signaling. As stomata opened, guard cells exhibited radially arranged cortical microtubules, which depolymerized into the cytosol when exposed to darkness and ABA. Suppression of microtubule disassembly by paclitaxel, a microtubule-stabilizing drug, significantly enhanced stomatal aperture under light, and partially blocked ABA- or darkness-induced stomatal closure. However, treatment with only the anti-microtubule drug, oryzalin, did not affect stomatal movement with or without external stimuli. Phosphatidic acid (PA) bound to a clade A type 2C protein phosphatase (PP2C), PP2CA, and deletion of PP2CA partially inhibited PA-induced microtubule depolymerization and stomatal closure. Moreover, microtubule reorganization was altered in the ABA-insensitive mutant pldα1, but not in the ABA-hypersensitive mutant pp2ca. We propose that a faithfully balanced reorganization of microtubules fulfills fundamental functions to enable the fast change of stomata in plant adaptive responses to developmental and environmental cues.     

Targeting KRAS Mutant Cancers with a Covalent G12C-Specific Inhibitor

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Single step genome-wide association studies based on genotyping by sequence data reveals novel loci for the litter traits of domestic pigs

In this study, data genotyping by sequence (GBS) was used to perform single step GWAS (ssGWAS) to identify SNPs associated with the litter traits in domestic pigs and search for candidate genes in the region of significant SNPs. After quality control, 167,355 high-quality SNPs from 532 pigs were obtained. Phenotypic traits on 2112 gilt litters from 532 pigs were recorded including total number born (TNB), number born alive (NBA), and litter weight born alive (LWB). A single-step genomic BLUP approach (ssGBLUP) was used to implement the genome-wide association analysis at a 5% genome-wide significance level. A total of 8, 23 and 20 significant SNPs were associated with TNB, NBA, and LWB, respectively, and these significant SNPs accounted for 62.78%, 79.75%, and 58.79% of genetic variance. Furthermore, 1 (SSC14: 16314857), 4 (SSC1: 81986236, SSC1: 66599775, SSC1: 161999013, and SSC1: 267883107), and 5 (SSC9: 29030061, SSC2: 32368561, SSC5: 110375350, SSC13: 45619882 and SSC13: 45647829) significant SNPs for TNB, NBA, and LWB were inferred to be novel loci. At SSC1, the AIM1 and FOXO3 genes were found to be associated with NBA; these genes increase ovarian reproductive capacity and follicle number and decrease gonadotropin levels. The genes SLC36A4 and INTU are involved in cell growth, cytogenesis and development were found to be associated with LWB. These significant SNPs can be used as an indication for regions in the Sus scrofa genome for variability in litter traits, but further studies are expected to confirm causative mutations.     

Genotypic Diversity among Campylobacter jejuni Isolates in a Commercial Broiler Flock

Analysis of nucleic acid polymorphism in the flagellin genes of Campylobacter jejuni was used to investigate genetic diversity among Campylobacter spp. in a commercial broiler flock. Three hundred single colonies of C. jejuni were isolated from fecal samples collected weekly for 3 weeks immediately before slaughter. Both the flaA and flaB genes were amplified by PCR, and the PCR product was digested with the restriction enzyme AluI. The fragments generated were then analyzed by agarose gel electrophoresis. Among the 300 recovered isolates, five different restriction fragment length polymorphism profiles were observed. Three of these profiles were dominant during the course of the study, and the other two profiles were detected at low frequency. Analysis of genetic variation in C. jejuni over the course of an experimental infection lasting 7 weeks indicated that there was no obvious drift in the flagellin gene type. These findings demonstrate that a range of bacterial genotypes can constitute the bacterial population within a commercial poultry flock, with the most likely sources of these types being multiple environmental exposure and/or genetic drift within the population. This degree of diversity must be considered in epidemiological analyses which utilize genetic typing methods that investigate Campylobacter contamination of any food source, including poultry, to ensure that the total gene pool for C. jejuni is evaluated.     

中国兰花蕉科植物花粉形态

使用扫描电镜及光学显微镜观察了国产兰花蕉科2种植物（兰花蕉及长萼兰花蕉）的花粉形态。它们的花粉粒呈豆形、两侧对称、异极、无萌发孔,中间部分的表面具稠密的条状雕纹,两端的为皱波状雕纹。两种花粉的雕纹有些区别。兰花蕉科花粉形态特征特别,不同于姜国其他7科的花粉,属特殊的花粉类型。     

A new species of the deepwater cardinalfishEpigonus (Perciformes: Epigonidae) from the Galápagos Islands

A new species of deepwater cardinal fish,Epigonus merleni, is described from a specimen found floating at the sea surface as a result of the eruption of Fernandina Volcano, Isla Fernandina, Galápagos Islands. It differs from all knownEpigonus in having the greatest number of lateral line scales (57) and the fewest gill rakers (17), as well as in several other characters.