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High-quality antiferromagnetic Mott insulator thin films of LaTiO3 (LTO) were epitaxially grown onto SrTiO3 (STO) (110) substrates using the pulsed laser deposition. The LTO/STO heterostructures are not only highly conducting and ferromagnetic, but also show Kondo effect, Shubnikov-de Haas (SdH) oscillations with a nonzero Berry phase of π, and low-field hysteretic negative magnetoresistance (MR). Angle-dependent SdH oscillations and a calculation of the thickness of the interfacial conducting layer indicate the formation of a 4-nm high mobility two-dimensional electron gas (2DEG) layer at the interface. Moreover, an amazingly large low-field negative MR of ∼61.8% is observed at 1.8 K and 200 Oe, which is approximately one to two orders of magnitude larger than those observed in other spin-polarized 2DEG oxide systems. All these results demonstrate that the 2DEG is spin-polarized and the 4-nm interfacial layer is ferromagnetic, which are attributed to the presence of magnetic Ti3+ ions due to interfacial oxygen vacancies and the diffusion of La3+ ions into the STO substrate. The localized Ti3+ magnetic moments couple to high mobility itinerant electrons under magnetic fields, giving rise to the observed low-field MR. Our work demonstrates the great potential of antiferromagnetic titanate oxide interface for designing spin-polarized 2DEG and spintronic devices. [ABSTRACT FROM AUTHOR]

Alternaria foliar diseases are important factors that pose a significant threat to yield in solanaceous crops. To clarify the diversity of large‐spored Alternaria species in China, diseased leaves of three solanaceous vegetables (potato, tomato and eggplant) were collected and used for fungal isolation. In total, 67 strains representing six species in section Porri of Alternaria were isolated, based on morphological characterizations and multilocus phylogenetic analyses. There were three known species (A. blumeae, A. linariae and A. solani), one new record of A. argyroxiphii and two new species, A. melongenicola sp. nov. and A. yichangensis sp. nov. The sequence analyses encompassed the internal transcribed spacer region of rDNA (ITS), glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), Alternaria major allergen (Alt a 1), translation elongation factor 1‐α (TEF1) and RNA polymerase second largest subunit (RPB2). To confirm pathogenicity, 15 representative strains were evaluated for their virulence under greenhouse conditions. The results revealed that they were able to induce leaf spot symptoms on potato, tomato and eggplant plants with a range of aggressive abilities. The present study provides a basis for the recognition and management of Alternaria foliar diseases. [ABSTRACT FROM AUTHOR]

Apple geminivirus 1 (AGV) in the genus Maldovirus of the family Geminiviridae was first identified infecting apple trees in the year 2015 in China. In this work, we characterized three isolates of the AGV in the Chinese pearleaf crabapple (Malus asiatica) in Inner Mongolia Autonomous Region. The viruses were detected by Illumina sequencing and its existence was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) amplification of an AGV fragment. Between the three AGV isolates and the initially characterized AGV isolate PL2015, the nucleotide sequence identities of the complete genome ranged from 91.2 to 91.7%, of the coat protein gene (V1) ranged from 95.4% to 97.3%, and of the replicase gene (C1) ranged from 87.3% to 88.0%. Phylogenetic analysis indicated that the three isolates formed a monophyletic group together with the AGV, separated from the current genera in the family Geminiviridae. This is the first description of the AGV infecting crabapples. [ABSTRACT FROM AUTHOR]

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In September 2019, two diseased plants of Campsis grandiflora showing the main symptom of witches' ‐broom (CgWB) were found in a nursery garden in Yangling, Shaanxi province, China. Partial 16S ribosomal RNA (F2nR2 region) and ribosomal protein (rp) genes of phytoplasmas were generated from the symptomatic plants by PCR amplification, and phytoplasma bodies were observed in the sieve tube elements of the CgWB samples under a transmission electron microscope, indicating phytoplasma infection in the two CgWB plants. Restriction fragment length polymorphism analysis of the F2nR2 region and similarity coefficient results suggested that the two associated phytoplasmas belong to two novel subgroups of 16SrI (aster yellows) group, designated as AK and AL. On the reconstructed phylogenetic trees based on F2nR2 regions and rp genes of phytoplasmas, respectively, the CgWB‐associated phytoplasmas clustered together with members of 16SrI subgroups. This was the first record of phytoplasmas infecting C. grandiflora worldwide. [ABSTRACT FROM AUTHOR]

In September 2017, oilseed mustard (Brassica juncea) showing symptoms of phyllody and witches'-broom, indicative of phytoplasma infection, was observed in Ordos, Inner Mongolia, China. Using universal primers P1/P7, the fragment encompassing phytoplasmal 16S rRNA, 16S–23S internal transcribed spacer region and partial 5′ end of 23S rRNA genes was amplified; the ribosomal protein (rp) genes (rplV-rpsC region) and the partial elongation factor TU (tuf) gene of phytoplasmas were amplified using primer pairs rpF1C/rp(I)R1A and fTufu/rTufu, respectively. The 16S rRNA, rp and tuf phylogenies suggested that both the B. juncea phyllody and witches'-broom associated phytoplasmas are closely related to members of 16SrVI (clover proliferation) group. Based on in silico restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes, the detected phytoplasmas were classified into 16SrVI-A subgroup. The in silico RFLP pattern is consistent with the actual RFLP pattern of the 16S rRNA genes. This was the first record of 16SrVI-A phytoplasma infecting B. juncea in China, probably the first case of phytoplasma on oilseed mustard as well. [ABSTRACT FROM AUTHOR]

Ten varieties of potted apple were subjected to thermotherapy coupled with in vitro meristem culture and in vivo shoot-tip grafting. Using reverse transcription-polymerase chain reaction assays prior to treatment, all treated apple varieties were infected by more than two viruses, and nine of ten varieties were infected by Apple chlorotic leaf spot virus ( ACLSV), Apple stem pitting virus ( ASPV) and Apple stem grooving virus ( ASGV). After treatment, the survivals of the two methods were more different. Total survival rates of the seven apple varieties ( YF9, XYF3, X2001, GL, HF, A123 and ZZ5) treated by thermotherapy coupled with in vitro meristem culture were 25.9% (14/54). The survival rate of YF9, XYF3, X2001, GL, YF6, JJ and XNH treated by thermotherapy coupled with in vivo shoot-tip grafting was from 33.3% to 75.0%, and the average rate (63.0%, 34/54) was twice than that of meristem culture. The virus-free apple plants were acquired only from in vitro variety HF and A123, and the elimination rate of A123 was highest, up to 71.4% (5/7). Fourteen apple survival grafting plants from five varieties ( YF9, XYF3, X2001, YF6 and XNH) were detected virus-free. The average elimination rate of the meristem culture and shoot-tip grafting was very close, 42.9% (6/14) and 41.2% (14/34), respectively. [ABSTRACT FROM AUTHOR]

Pepper witches' broom (PWB) disease was observed in a field in Yangling, Shaanxi Province, China. The result of mechanical inoculation test for this disease was negative. Phytoplasma-like bodies were observed in ultrathin sections of petiole tissues of symptomatic samples. 16S rRNA gene and tuf gene of phytoplasma were amplified from the total DNA of symptomatic samples. Phylogeny analysis of the 16S rRNA gene and tuf gene suggested that the pepper witches' broom associated phytoplasma belongs to the subgroup 16SrI-B, which was confirmed by the RFLP analysis of the 16S rRNA gene. The phytoplasma subgroup 16SrI-B was also detected in the vector Cicadella viridis trapped from the infected field. To our knowledge, this is the first report of 16SrI-B phytoplasma causing pepper witches' broom in China. [ABSTRACT FROM AUTHOR]

In 2011, typical symptoms suggestive of phytoplasma infection such as reddening of leaves were observed in peach trees in Fuping, Shaanxi Province, China. Phytoplasma-like bodies were observed by transmission electron microscope in the petiole tissues of symptomatic peach trees. Products of c. 1.2 kb were generated from all symptomatic peach leaf samples by a nested polymerase chain reaction using phytoplasma universal primer pairs P1⁄P7 and R16F2n⁄R16R2, whereas no such amplicon was obtained from healthy samples. Results of phylogenetic analysis and restriction fragment length polymorphism suggested that the phytoplasma associated with such peach red leaf disease was a member of subgroup 16SrI-C. To our knowledge, this is the first record of 16SrI-C subgroup phytoplasma occurred in peach tree in China. [ABSTRACT FROM AUTHOR]

In 2010 and 2011, the Puna chicory flat stem (PCFS) symptom was observed in an experimental field around Yangling, Shaanxi Province, China. Pleomorphic phytoplasma-like bodies were observed in the phloem sieve tube elements of symptomatic plants under transmission electron microscope (TEM). The presence of phytoplasma was further confirmed by a nested polymerase chain reaction (PCR), which amplified a 1.2 kb fragment using universal primer pairs P1/P6 followed by further amplification using primer pairs R16F2n/R16R2. The 1.1 kb 16S rRNA gene fragments were obtained by nested PCR with primer pairs P1/P6 followed by 16SrV group-specific primer pairs R16(V)F1/R16(V)R1 and indicated that the PCFS phytoplasma was closely related to the elm yellows (EY) group (16SrV). Phylogenetic analysis and restriction fragment length polymorphism (RFLP) analysis demonstrated that the PCFS phytoplasma belongs to subgroup 16SrV-B. This is the first report of Puna chicory disease associated with a subgroup 16SrV-B of phytoplasma in China. [ABSTRACT FROM AUTHOR]

Preparation of trisubstituted alkenes from low-activity β-diketones and aldehydes with aluminum chloride as catalyst has been studied. The frequently used catalyst AlCl 3 is used for the first time to promote this condensation. The procedure is a convenient, low toxicity, and highly efficient method for industrial synthesis of trisubstituted alkenes in high yield. [ABSTRACT FROM AUTHOR]

In July, 2011, alfalfa plants were observed in Yangling, Shaanxi Province, China with typical witches' broom symptoms. The presence of phytoplasma was confirmed by transmission electron microscopy and a nested PCR, which amplified a 1.2-kb fragment using universal primer pairs P1/P6 followed by R16F2n/R2. Sequence, phylogeny and RFLP analyses showed that the alfalfa witches' broom disease was associated with a phytoplasma of group 16SrV, subgroup V-B. This is the first record of the 16SrV phytoplasma group infecting alfalfa plants. [ABSTRACT FROM AUTHOR]

• Using one-step 'seamless' method to construct the full-length cDNA clone of ASGV. • Using the 'pure' cDNA clone established infection on herbaceous and woody plants. • Infectivity test demonstrated that ASGV JL-SG is not seed-transmissible. • Nicotiana benthamiana is not a host of ASGV JL-SG. Apple stem grooving virus (ASGV) belongs to the genus Capillovirus within the family Betaflexiviridae. In this work, we described the construction of full-length infectious cDNA clones of ASGV isolate jilin-shaguo (JL-SG) using the Gibson Assembly approach (New England BioLabs). The isolate was previously detected in a Chinese pear-leaf crab apple (Malus asiatica Nakai.) in Baicheng, Jilin province, China. Two full-length cDNA clones of ASGV JL-SG were obtained, and they are identical to each other in sequence. The full-length cDNA clone was infectious on Chenopodium quinoa , Nicotiana glutinosa , and N. occidentalis 37B via agroinfiltration. Through sap inoculation, the infection was additionally spread to C. amaranticolor. N. benthamiana could not be infected, neither through agroinfiltration nor sap inoculation. In infected herbaceous plants, typical ASGV particles with morphology of flexuous filaments were observed by transmission electron microscope (TEM). Moreover, seeds of infected N. glutinosa and N. occidentalis 37B were collected and germinated, the seedlings were ASGV-free in RT-PCR test, suggesting ASGV JL-SG is not seed-transmissible in the tested Nicotiana species. In addition, the cDNA clone was agroinfiltrated into seedlings of Malus pumila cv. Fuji. The infection was symptomless, and can be spread to C. quinoa via sap inoculation, causing typical symptoms. ASGV JL-SG was also detected by RT-PCR in the infected Fuji plants, however, no virion was observed by TEM. [ABSTRACT FROM AUTHOR]