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Guo Q.,Missouri State University | Honesty S.,Missouri State University | Xu M.L.,Missouri State University | Xu M.L.,Ningxia Forestry Institute | And 5 more authors.
Phytopathology | Year: 2014

Grapevine vein clearing virus (GVCV) is a new badnavirus in the family Caulimoviridae that is closely associated with an emerging veinclearing and vine decline disease in the Midwest region of the United States. It has a circular, double-stranded DNA genome of 7,753 bp that is predicted to encode three open reading frames (ORFs) on the plus-strand DNA. The largest ORF encodes a polyprotein that contains domains for a reverse transcriptase (RT), an RNase H, and a DNA-binding zinc-finger protein (ZF). In this study, two genomic regions, a 570-bp region of the RT domain and a 540-bp region of the ZF domain were used for an analysis of the genetic diversity of GVCV populations. In total, 39 recombinant plasmids were sequenced. These plasmids consisted of three individual clones from each of 13 isolates sampled from five grape varieties in three states. The sequence variants of GVCV could not be phylogenetically grouped into clades according to geographical location and grape variety. Codons of RT or ZF regions are subject to purifying selection pressure. Quantitative polymerase chain reaction assays indicated that GVCV accumulates abundantly in the petioles and least in the root tip tissue. Upon grafting of GVCV-infected buds onto four major grape cultivars, GVCV was not detected in the grafted 'Chambourcin' vine but was present in the grafted 'Vidal Blanc', 'Cayuga White', and 'Traminette' vines, suggesting that Chambourcin is resistant to GVCV. Furthermore, seven nucleotides were changed in the sequenced RT and ZF regions of GVCV from a grafted Traminette vine and one in the sequenced regions of GVCV from grafted Cayuga White but no changes were found in the sequenced regions of GVCV in the grafted Vidal Blanc. The results provide a genetic snapshot of GVCV populations, which will yield knowledge important for monitoring GVCV epidemics and for preventing the loss of grape production that is associated with GVCV. © 2014 The American Phytopathological Society.

Li Z.,Ningxia University | Li Z.,Ningxia Forestry Institute | Xie Y.,Ningxia University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Desertification is one of most serious problems which affect eco-construction and agricultural production in Ningxia and other arid and semiarid areas in China. To study the effects of tree branch application patterns on physicochemical property and microbial activity of desertified soil, pruned tree branches were collected as soil amended materials from local common trees of farmland shelterbelt, and a two-year study was conducted from October 2011 to October 2013 in Yinchuan Belly Desert of Ningxia. Four experimental treatments were set up, including 1) CK (no tree branches applied), 2) CI (5% (w/w) grinded poplar branch chips incorporated into 0-20 cm soil layer), 3) CM (grinded poplar branch chips mulched on soil surface with a thickness of about 3 cm) and 4) CI+BM (5% (w/w) of grinded poplar branch chips incorporated into 0-20 cm soil layer plus ungrinded willow branches crisscross mulched on soil surface with a thickness of 30-40 cm and a coverage of 50%-60%). The 0-20 cm soils were sampled and measured in October 2012 and October 2013 respectively. Results showed as follows: To physical properties, compared with CK, CI and CI+BM decreased bulk density yet increased total porosity and field water holding capacity of desertified soil in 2012 and 2013 (P<0.05), and there was no significant difference between the two on other physical properties except CI+BM had more effect on increasing total porosity than CI in 2013; CM significantly increased total porosity in 2012 (P<0.05), but had no effect on other indicators of physical properties compared with CK in 2012 and 2013. To chemical properties, compared with CK, both CI and CI+BM increased organic carbon, available phosphorus (P) and available potassium (K) in 2012 and then increased total salt, organic carbon, total nitrogen (N), total P, alkaline N, available P and available K in 2013 (P<0.05), yet had no effects on pH value (P>0.05); furthermore, CI+BM had more effect on increasing total N than CI in 2013; compared with CK, CM increased total available P and available K in 2012 and then increased pH value, total N, alkaline N, available P and available K in 2013 (P<0.05), yet had no effect on other chemical properties compared with CK (P>0.05). To biological properties, it showed an order of CI+BM>CI>CM>CK on enhancing microbial activity, CI and CI+BM enhanced soil respiration, microbial number, urease activity and catalase activity compared with CK in 2012 and 2013 (P<0.05), and CI+BM tended to have more effect on enhancing microbial activity than CI; and also compared with CK, CM also increased soil respiration, urease activity and catalase activity in 2012 and 2013 (P<0.05), as well as increased bacteria and fungi number in 2012, yet had no effect on microbial number in 2013. An analysis indicated that soil physical, chemical and biological properties were improved in 2013 than in 2012. Additionally, a correlation analysis indicated that most of measured soil indicators were significantly or highly significantly correlated with organic carbon content (except pH value and total K in 2013), and organic carbon content presented a tendency of CI+BM>CI>CM>CK among treatments in 2012 and 2013; a comprehensive index SQI (soil quality index), which was applied for assessing soil quality, also presented a tendency of CI+BM>CI>CM>CK in 2012 (0.907, 0.678, 0.259 and 0.105 respectively) and 2013 (0.926, 0.828, 0.258 and 0.136 respectively). In summary, all tree application patterns have positive effects on improving soil properties or quality during experimental period, which presents a tendency of CI+BM>CI>CM>CK among treatments. Above study provides a successful case for ecological management and agricultural production for Ningxia and other arid and semiarid areas of North China; meanwhile it also may be beneficial to tree branch recycling and utilization. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.

Ni X.-L.,Northwest University, China | Ni X.-L.,Ningxia Forestry Institute | Su H.,Northwest University, China | Zhou Y.-F.,Institute of Botany of Shaanxi Province | And 2 more authors.
Physiologia Plantarum | Year: 2015

Some species of Allium in Liliaceae have fistular leaves. The fistular lamina of Allium fistulosum undergoes a process from solid to hollow during development. The aims were to reveal the process of fistular leaf formation involved in programmed cell death (PCD) and to compare the cytological events in the execution of cell death to those in the unusual leaf perforations or plant aerenchyma formation. In this study, light and transmission electron microscopy were used to characterize the development of fistular leaves and cytological events. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays and gel electrophoresis were used to determine nuclear DNA cleavage during the PCD. The cavity arises in the leaf blade by degradation of specialized cells, the designated pre-cavity cells, in the center of the leaves. Nuclei of cells within the pre-cavity site become TUNEL-positive, indicating that DNA cleavage is an early event. Gel electrophoresis revealed that DNA internucleosomal cleavage occurred resulting in a characteristic DNA ladder. Ultrastructural analysis of cells at the different stages showed disrupted vacuoles, misshapen nuclei with condensed chromatin, degraded cytoplasm and organelles and emergence of secondary vacuoles. The cell walls degraded last, and residue of degraded cell walls aggregated together. These results revealed that PCD plays a critical role in the development of A. fistulosum fistular leaves. The continuous cavity in A. fistulosum leaves resemble the aerenchyma in the pith of some gramineous plants to improve gas exchange. © 2014 Scandinavian Plant Physiology Society.

Zhang Y.-M.,China Agricultural University | Zhang Y.-M.,Missouri State University | Ni X.-L.,Ningxia Forestry Institute | Ni X.-L.,Northwest University, China | And 2 more authors.
Journal of Integrative Agriculture | Year: 2013

Non-expressor of pathogenesis-related genes 1 (NPR1) plays a significant role in the defense responses of plants to pathogens by regulating the expression of defense-related genes. In the present study, we isolated two NPR1 genes from Vitis aestivalis cv. Norton and Vitis vinifera cv. Cabernet Sauvignon, which were referred to as VaNPR1.1 and VvNPR1. 1-CS, respectively. They encode a protein of 584 amino acids with a predicted molecular weight of 64.8 kDa and a theoretical isoelectric point (PI) of 5.74. The predicted amino acid sequences of VaNPR1.1 and VvNPR1.1-CS differ by only one amino acid. Over-expression of VaNPR1.1 gene in Arabidopsis npr1-1 mutant plants restores the transcriptional expression of AtPR-1 gene, though not to the full scale. This result demonstrated that a grapevine VaNPR1.1 possesses a similar function to the Arabidopsis NPR1 in the regulation of defense-related genes. Over-expression of VaNPR1.1 in transgenic Arabidopsis plant increased tolerance to salinity, but had no effect on the drought tolerance. We conclude that VaNPR1.1 is a functional ortholog of AtNPR1 and also involved in grapevine's response to the salt stress. © 2013 Chinese Academy of Agricultural Sciences.

Yang Y.,Southwest University | Yang Y.,Ningxia Forestry Institute | Li C.,Southwest University | Li C.,Ningxia Forestry Institute | And 3 more authors.
Environmental Science and Pollution Research | Year: 2013

Pterocarya stenoptera is a native deciduous tree species and a candidate for reforestation in the riparian zones of the Three Gorges Reservoir Region of Yangtze River in China. Water treatments of continuous flooding (CF) and periodic flooding-drought (PF) were applied to examine the growth dynamics of 4-month-old P. stenoptera seedlings and its effects on soil chemical properties. Results showed that P. stenoptera seedlings in both CF and PF significantly decreased leaf biomass accumulation and the height and diameter growth as compared to that in control (CK; treatment with well-watered, well-drained soil), respectively. There was no significant difference in stem biomass among the three groups, but root biomass in PF showed severe reduction compared to that in both CK and CF. Total biomass in PF was significantly decreased compared to that in CK, but comparable to that in CF. Furthermore, no significant difference was found between CF and CK in total biomass. Water treatments in the unplanted soil pots significantly influenced soil pH, soil organic matter (OM), total nitrogen (TN), and alkali hydrolysable nitrogen (AN) contents, in contrast to no significant effects in total phosphorus (TP), total potassium (TK), available phosphorus (AP), and available potassium (AK) contents. In P. stenoptera soils, there were significant effects by water treatment, time, and treatment × time in the eight tested soil chemical properties, except treatment in TK and time effect in OM content. Compared to unplanted soils, the growth of P. stenoptera seedlings significantly increased soil pH value and OM, TN, TP, and TK contents, while decreasing AN, AP, and AK contents in CK group, augmented the mean value of each of the tested soil chemical properties with an exception of AK content in CF group, and increased soil pH value and TN, AN, TP, and AP contents with no significant differences in OM, TK, and AK contents in PF group. Given the fact that TN and TP contents significantly increased in P. stenoptera soils as compared to those in unplanted soils, growth of P. stenoptera seedlings should be a successful candidate for restoration within the highly dynamic hydrologic zone of the riparian zones of the Three Gorges Reservoir Region. © 2013 Springer-Verlag Berlin Heidelberg.

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