Locations where <i>Plutella xylostella</i> populations were sampled in China.

<p>Arrows indicate possible migration routes based on shared haplotypes. The software Adobe Photoshop CS6, Micosoft PowerPoint 2013 and Micosoft Word 2013 were used to create and modify this map.</p

Results of a Mantel test showing the correlation between pairwise Fst values and the logarithm of geographic distances of Chinese populations of <i>Plutella xylostella</i>.

<p>Reduced major axis (RMA) analyses were calculated from 10000 randomizations.</p

Data_Sheet_1_SbbR/SbbA, an Important ArpA/AfsA-Like System, Regulates Milbemycin Production in Streptomyces bingchenggensis.docx

<p>Milbemycins, a group of 16-membered macrolide antibiotics, are used widely as insecticides and anthelmintics. Previously, a limited understanding of the transcriptional regulation of milbemycin biosynthesis has hampered efforts to enhance antibiotic production by engineering of regulatory genes. Here, a novel ArpA/AfsA-type system, SbbR/SbbA (SBI_08928/SBI_08929), has been identified to be involved in regulating milbemycin biosynthesis in the industrial strain S. bingchenggensis BC04. Inactivation of sbbR in BC04 resulted in markedly decreased production of milbemycin, while deletion of sbbA enhanced milbemycin production. Electrophoresis mobility shift assays (EMSAs) and DNase I footprinting studies showed that SbbR has a specific DNA-binding activity for the promoters of milR (the cluster-situated activator gene for milbemycin production) and the bidirectionally organized genes sbbR and sbbA. Transcriptional analysis suggested that SbbR directly activates the transcription of milR, while represses its own transcription and that of sbbA. Moreover, 11 novel targets of SbbR were additionally found, including seven regulatory genes located in secondary metabolite biosynthetic gene clusters (e.g., sbi_08420, sbi_08432, sbi_09158, sbi_00827, sbi_01376, sbi_09325, and sig24_sbh) and four well-known global regulatory genes (e.g., glnR_sbh, wblA_sbh, atrA_sbh, and mtrA/B_sbh). These data suggest that SbbR is not only a direct activator of milbemycin production, but also a pleiotropic regulator that controls the expression of other cluster-situated regulatory genes and global regulatory genes. Overall, this study reveals the upper-layer regulatory system that controls milbemycin biosynthesis, which will not only expand our understanding of the complex regulation in milbemycin biosynthesis, but also provide a basis for an approach to improve milbemycin production via genetic manipulation of SbbR/SbbA system.</p

Comparison of <i>mtCO1</i> haplotype frequency distributions in samples of <i>Plutella xylostella</i> from South Korean (top) and in <i>Plutella xylostella</i> populations across China (bottom).

<p>Haplotypes with frequency ≤ 2 are not shown.</p

Statistical parsimony network of <i>Plutella xylostella</i> mt<i>COI</i> haplotypes.

<p>The red and blue circles represents shared and unique haplotypes, respectively. Haplotype names are beside the circles. The small circles indicate the presence of missing intermediates, while the connections are based on the set of plausible solutions with a 95% of parsimony probability.</p

UPGMA dendrogram of 23 populations of <i>Plutella xylostella</i> in China based on ISSR markers.

<p>UPGMA dendrogram of 23 populations of <i>Plutella xylostella</i> in China based on ISSR markers.</p

Insight into the Migration Routes of <i>Plutella xylostella</i> in China Using mt<i>COI</i> and ISSR Markers

<div><p>The larvae of the diamondback moth, <i>Plutella xylostella</i>, cause major economic losses to cruciferous crops, including cabbage, which is an important vegetable crop in China. In this study, we used the mitochondrial <i>COI</i> gene and 11 ISSR markers to characterize the genetic structure and seasonal migration routes of 23 <i>P</i>. <i>xylostella</i> populations in China. Both the mitochondrial and nuclear markers revealed high haplotype diversity and gene flow among the populations, although some degree of genetic isolation was evident between the populations of Hainan Island and other sampling sites. The dominant haplotypes, LX1 and LX2, differed significantly from all other haplotypes both in terms of the number of individuals with those haplotypes and their distributions. Haplotypes that were shared among populations revealed that <i>P</i>. <i>xylostella</i> migrates from the lower reaches of the Yangtze River to northern China and then to northeastern China. Our results also revealed another potential migration route for <i>P</i>. <i>xylostella</i>, i.e., from southwestern China to both northwestern and southern China.</p></div

Results of genetic diversity and neutrality tests based on <i>mtCOI</i> sequences for populations of <i>Plutella xylostella</i> in China.

<p>H, number of haplotypes; Hd, haplotype diversity; Pi, nucleotide diversity; k, average number of nucleotide differences.</p><p>*P<0.05</p><p>**P<0.01.</p><p>Results of genetic diversity and neutrality tests based on <i>mtCOI</i> sequences for populations of <i>Plutella xylostella</i> in China.</p

Novel Plant Growth Regulator Guvermectin from Plant Growth-Promoting Rhizobacteria Boosts Biomass and Grain Yield in Rice

Food is a fundamental human right, and global food security is threatened by crop production. Plant growth regulators (PGRs) play an essential role in improving crop yield and quality, and this study reports on a novel PGR, termed guvermectin (GV), isolated from plant growth-promoting rhizobacteria, which can promote root and coleoptile growth, tillering, and early maturing in rice. GV is a nucleoside analogue like cytokinin (CK), but it was found that GV significantly promoted root and hypocotyl growth, which is different from the function of CK in Arabidopsis. The Arabidopsis CK receptor triple mutant ahk2-2 ahk3-3 cre1-12 still showed a GV response. Moreover, GV led different growth-promoting traits from auxin, gibberellin (GA), and brassinosteroid (BR) in Arabidopsis and rice. The results from a four-year field trial involving 28 rice varieties showed that seed-soaking treatment with GV increased the yields by 6.2 to 19.6%, outperforming the 4.0 to 10.8% for CK, 1.6 to 16.9% for BR, and 2.2 to 7.1% for GA-auxin-BR mixture. Transcriptome analysis demonstrated that GV induced different transcriptome patterns from CK, auxin, BR, and GA, and SAUR genes may regulate GV-mediated plant growth and development. This study suggests that GV represents a novel PGR with a unique signal perception and transduction pathway in plants

Interdiffusion Reaction-Assisted Hybridization of Two-Dimensional Metal–Organic Frameworks and Ti₃C₂T_<i>x</i> Nanosheets for Electrocatalytic Oxygen Evolution

Two-dimensional (2D) metal–organic framework (MOF) nanosheets have been recently regarded as the model electrocatalysts due to their porous structure, fast mass and ion transfer through the thickness, and large portion of exposed active metal centers. Combining them with electrically conductive 2D nanosheets is anticipated to achieve further improved performance in electrocatalysis. In this work, we <i>in situ</i> hybridized 2D cobalt 1,4-benzenedicarboxylate (CoBDC) with Ti₃C₂T_<i>x</i> (the MXene phase) nanosheets <i>via</i> an interdiffusion reaction-assisted process. The resulting hybrid material was applied in the oxygen evolution reaction and achieved a current density of 10 mA cm^–2 at a potential of 1.64 V <i>vs</i> reversible hydrogen electrode and a Tafel slope of 48.2 mV dec^–1 in 0.1 M KOH. These results outperform those obtained by the standard IrO₂-based catalyst and are comparable with or even better than those achieved by the previously reported state-of-the-art transition-metal-based catalysts. While the CoBDC layer provided the highly porous structure and large active surface area, the electrically conductive and hydrophilic Ti₃C₂T_<i>x</i> nanosheets enabled the rapid charge and ion transfer across the well-defined Ti₃C₂T_<i>x</i>–CoBDC interface and facilitated the access of aqueous electrolyte to the catalytically active CoBDC surfaces. The hybrid nanosheets were further fabricated into an air cathode for a rechargeable zinc–air battery, which was successfully used to power a light-emitting diode. We believe that the <i>in situ</i> hybridization of MXenes and 2D MOFs with interface control will provide more opportunities for their use in energy-based applications