A (3,8)-Connected Metal-Organic Framework with Bending Dicarboxylate Linkers for C2H2/CO2 Separation.

Herein, by replacement of the linear terephthalate linker with the bending 2,5-thiophenedicarboxylate (tdc2-) linker in the typical (3,9)-connected metal-organic framework, with a reduced 8-connected hydroxyl-centered trinuclear cluster, a new (3,8)-connected network, [Ni3(µ3-OH)(tdc)3(tpp)] [DZU-1; tpp = 2,4,6-tris(4-pyridyl)pyridine], was synthesized. The modified pore environment enables DZU-1 to selectively adsorb C2H2 over CO2 in an efficient manner.

Corrigendum: Expression of Pumpkin CmbHLH87 Gene Improves Powdery Mildew Resistance in Tobacco.

[This corrects the article DOI: 10.3389/fpls.2020.00163.].

Expression of Pumpkin CmbHLH87 Gene Improves Powdery Mildew Resistance in Tobacco.

Powdery mildew (PM), caused by Podosphaera xanthii, is a major threat to the global cucurbit yield. The molecular mechanisms underlying the PM resistance of pumpkin (Cucurbita moschata Duch.) are largely unknown. A homolog of the basic helix-loop-helix (bHLH) transcription factor was previously identified through a transcriptomic analysis of a PM-resistant pumpkin. In this study, this bHLH homolog in pumpkin has been functionally characterized. CmbHLH87 is present in the nucleus. CmbHLH87 expression in the PM-resistant material was considerably downregulated by PM; and abscisic acid, methyl jasmonate, ethephon, and NaCl treatments induced CmbHLH87 expression. Ectopic expression of CmbHLH87 in tobacco plants alleviated the PM symptoms on the leaves, accelerated cell necrosis, and enhanced H2O2 accumulation. The expression levels of PR1a, PR5, and NPR1 were higher in the PM-infected transgenic plants than in PM-infected wild-type plants. Additionally, the chlorosis and yellowing of plant materials were less extensive and the concentration of bacteria at infection sites was lower in the transgenic tobacco plants than in the wild-type plants in response to bacterial wilt and scab pathogens. CmbHLH87 may be useful for genetic engineering of novel pumpkin cultivars in the future.

Transcriptome profiling of pumpkin (Cucurbita moschata Duch.) leaves infected with powdery mildew.

Cucurbit powdery mildew (PM) is one of the most severe fungal diseases, but the molecular mechanisms underlying PM resistance remain largely unknown, especially in pumpkin (Cucurbita moschata Duch.). The goal of this study was to identify gene expression differences in PM-treated plants (harvested at 24 h and 48 h after inoculation) and untreated (control) plants of inbred line "112-2" using RNA sequencing (RNA-Seq). The inbred line "112-2" has been purified over 8 consecutive generations of self-pollination and shows high resistance to PM. More than 7600 transcripts were examined in pumpkin leaves, and 3129 and 3080 differentially expressed genes (DEGs) were identified in inbred line "112-2" at 24 and 48 hours post inoculation (hpi), respectively. Based on the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway database and GO (Gene Ontology) database, a complex regulatory network for PM resistance that may involve hormone signal transduction pathways, transcription factors and defense responses was revealed at the transcription level. In addition, the expression profiles of 16 selected genes were analyzed using quantitative RT-PCR. Among these genes, the transcript levels of 6 DEGs, including bHLH87 (Basic Helix-loop-helix transcription factor), ERF014 (Ethylene response factor), WRKY21 (WRKY domain), HSF (heat stress transcription factor A), MLO3 (Mildew Locus O), and SGT1 (Suppressor of G-Two Allele of Skp1), in PM-resistant "112-2" were found to be significantly up- or down-regulated both before 9 hpi and at 24 hpi or 48 hpi; this behavior differed from that observed in the PM-susceptible material (cultivar "Jiujiangjiaoding"). The transcriptome data provide novel insights into the response of Cucurbita moschata to PM stress and are expected to be highly useful for dissecting PM defense mechanisms in this major vegetable and for improving pumpkin breeding with enhanced resistance to PM.

[A new neolignan from fruit of Solanum torvum].

One new neolignan identified as 2, 3-( trans) -dihydro-2-(4-hydroxy-3-methoxyphenyl) -3-[(beta-D-glucopyranosyloxy) methyl]-7-methoxybenzofuran-5-propenoic acid (1) and five known steroidal glycosides namely torvoside A(2), torvoside C(3), torvoside H(4), solanolactoside A (5), (25S)-6alpha-hydroxy-5alpha-spirostan-3-one-6-0-[alpha-L-rhamnopyranosyl-(1-->3-beta3)-beta-D-D-quinovopyr-anoside] (6) were isolated from the fruits of Solanum torvum. Their structures were elucidated on the basis of 1D, 2D NMR and MS spectroscopic analysis.

Reduced tolerance to abiotic stress in transgenic Arabidopsis overexpressing a Capsicum annuum multiprotein bridging factor 1.

BACKGROUND: The pepper fruit is the second most consumed vegetable worldwide. However, low temperature affects the vegetative development and reproduction of the pepper, resulting in economic losses. To identify cold-related genes regulated by abscisic acid (ABA) in pepper seedlings, cDNA representational difference analysis was previously performed using a suppression subtractive hybridization method. One of the genes cloned from the subtraction was homologous to Solanum tuberosum MBF1 (StMBF1) encoding the coactivator multiprotein bridging factor 1. Here, we have characterized this StMBF1 homolog (named CaMBF1) from Capsicum annuum and investigated its role in abiotic stress tolerance. RESULTS: Tissue expression profile analysis using quantitative RT-PCR showed that CaMBF1 was expressed in all tested tissues, and high-level expression was detected in the flowers and seeds. The expression of CaMBF1 in pepper seedlings was dramatically suppressed by exogenously supplied salicylic acid, high salt, osmotic and heavy metal stresses. Constitutive overexpression of CaMBF1 in Arabidopsis aggravated the visible symptoms of leaf damage and the electrolyte leakage of cell damage caused by cold stress in seedlings. Furthermore, the expression of RD29A, ERD15, KIN1, and RD22 in the transgenic plants was lower than that in the wild-type plants. On the other hand, seed germination, cotyledon greening and lateral root formation were more severely influenced by salt stress in transgenic lines compared with wild-type plants, indicating that CaMBF1-overexpressing Arabidopsis plants were hypersensitive to salt stress. CONCLUSIONS: Overexpression of CaMBF1 in Arabidopsis displayed reduced tolerance to cold and high salt stress during seed germination and post-germination stages. CaMBF1 transgenic Arabidopsis may reduce stress tolerance by downregulating stress-responsive genes to aggravate the leaf damage caused by cold stress. CaMBF1 may be useful for genetic engineering of novel pepper cultivars in the future.

Poly[diaqua-(µ-4,4'-bipyridine-κN:N')[µ-2,2'-(p-phenyl-enedi-oxy)diacetato-κO:O']cadmium].

In the title compound, [Cd(C(10)H(8)O(6))(C(10)H(8)N(2))(H(2)O)(2)](n), the Cd(II) ion has inversion symmetry and is coordinated by O atoms from two water mol-ecules and two bridging 2,2'-(µ-p-phenyl-enedi-oxy)diacetate ligands and two N atoms from two 4,4'-bipyridine ligands, giving a slightly distorted octa-hedral geometry. The diacetate and 4,4'-bipyridine ligands also lie across inversion centers. The bridging ligands form layers parallel to (11[Formula: see text]), with adjacent layers inter-connected via O-H⋯O hydrogen bonds between the coordinated water mol-ecules and the carboxyl-ate O atoms, giving a three-dimensional supra-molecular architecture.

Bis(4-pyrid-yl) disulfide-2,2'-[(p-phenyl-enebis(-oxy)]diacetic acid (1/1).

The asymmetric unit of the title 1:1 co-crystal, C(10)H(8)N(2)S(2)·C(10)H(10)O(6), comprises two half-mol-ecules, the bis-(4-pyrid-yl) disulfide having twofold rotational symmetry and the 2,2'-[(p-phenyl-enebis(-oxy)]diacetic acid having crystallographic inversion symmetry. In the disulfide mol-ecule, the dihedral angle between the two pyridine rings is 86.8 (1)°, while the carboxyl groups of the substituted quinone lie essentially in the plane of the benzene ring [dihedral angle = 5.3 (1)°]. In the crystal, the components are linked via inter-molecular O-H⋯N hydrogen bonds into zigzag chains which extend along c and are inter-linked through C-H⋯π associations.