Genetic Basis Identification of a NLR Gene, TaRGA5-like, That Confers Partial Powdery Mildew Resistance in Wheat SJ106.

Wheat powdery mildew is an important fungal disease that seriously jeopardizes wheat production, which poses a serious threat to food safety. SJ106 is a high-quality, disease-resistant spring wheat variety; this disease resistance is derived from Wheat-wheatgrass 33. In this study, the powdery mildew resistance genes in SJ106 were located at the end of chromosome 6DS, a new disease resistance locus tentatively named PmSJ106 locus. This interval was composed of a nucleotide-binding leucine-rich repeat (NLR) gene cluster containing 19 NLR genes. Five NLRs were tandem duplicated genes, and one of them (a coiled coil domain-nucleotide binding site-leucine-rich repeat (CC-NBS-LRR; CNL) type gene, TaRGA5-like) expressed 69-836-fold in SJ106 compared with the susceptible control. The genome DNA and cDNA sequences of TaRGA5-like were amplified from SJ106, which contain several nucleotide polymorphisms in LRR regions compared with susceptible individuals and Chinese Spring. Overexpression of TaRGA5-like significantly increased resistance to powdery mildew in susceptible receptor wheat Jinqiang5. However, Virus induced gene silence (VIGS) of TaRGA5-like resulted in only a small decrease of SJ106 in disease resistance, presumably compensated by other NLR duplicated genes. The results suggested that TaRGA5-like confers partial powdery mildew resistance in SJ106. As a member of the PmSJ106 locus, TaRGA5-like functioned together with other NLR duplicated genes to improve wheat resistance to powdery mildew. Wheat variety SJ106 would become a novel and potentially valuable germplasm for powdery mildew resistance.

Genome-wide identification of TaCIPK gene family members in wheat and their roles in host response to Blumeria graminis f. sp. tritici infection.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease affecting wheat crops worldwide. Functional genes can be activated in response to Bgt inoculations. Calcineurin B-like protein (CBL) together with CBL-interacting protein kinase (CIPK) forms the CBL-CIPK protein complex that participates in Ca2+ sensor kinase-related signaling pathways responding to abiotic and biotic stresses. In this study, we performed a genome-wide screening and identified 27 CIPK subfamilies (123 CIPK transcripts, TaCIPKs) including 55 new and 47 updated TaCIPKs in wheat. Phylogenetic analysis revealed that 123 TaCIPKs could be divided into four groups. Segmental duplications and tandem repeats promoted the expansion of the TaCIPK family. Gene function was further evidenced by differences in gene structure, cis-elements, and protein domains. TaCIPK15-4A was cloned in this study. TaCIPK15-4A contained 17 serine, seven tyrosine, and 15 threonine phosphorylation sites and localized in the plasma membrane and cytoplasm. TaCIPK15-4A expression was induced after Bgt inoculation. Virus-induced gene silencing and overexpression experiments indicated that TaCIPK15-4A could play a positive role in wheat disease resistance to Bgt. Overall, these results provide insights into the role of the TaCIPK gene family in wheat resistance and could be beneficial for further research to prevent Bgt infection.

Functional Traits of Male and Female Leaves of Hippophae tibetana on the Eastern Edge of the Tibetan Plateau and Their Altitudinal Variability.

To date, there have been few studies of the functional traits of the dioecious Hippophae tibetana Schlecht leaves, either male or female, in response to ecological factors such as altitude. Elucidating these relationships will establish an important scientific basis for vegetation restoration and reconstruction of the Tibetan Plateau ecosystem. The natural populations of H. tibetana, distributed across three field sites, at 2868 m, 3012 m and 3244 m, in Tianzhu, Gansu, were studied by field survey sampling and laboratory analysis. In particular, the adaptions of leaf functional traits to elevation in these dioecious plants were analyzed. The results show that: (1) there is no "midday depression" of photosynthetic activity in either male or female plants. Over a one-day period, the net photosynthetic rate (Pn) and transpiration rate (Tr) of H. tibetana female plants were higher than those of male plants (p < 0.05). This correlated to the period of vigorous fruit growth in the female plant. The measured Pn and Tr were maximal at the intermediate altitude (3012 m). The light compensation point (LCP) of the leaves of male and female plants were 57.6 and 43.2 µmol·m−2·s−1, respectively, and the light saturation points (LSP) of the leaves were 1857.6 and 1596.8 µmol·m−2·s−1. (2) Altitude had a significant effect on plant and leaf functional traits of male and female H. tibetana (p < 0.05), and no significant difference was noted between plants at the same altitude. The values for leaf area (LA), specific leaf weight (LMA), leaf phosphorus content per unit mass (Pmass) and leaf phosphorus content per unit area (Parea) were also maximal at the intermediate altitude. Leaf nitrogen content per unit area (Narea) and leaf nitrogen content per unit mass (Nmass) increased with altitude. This indicated that the functional traits of male and female plants and leaves of H. tibetana showed a strong "trade-off relationship" with altitude. (3) Pearson correlation analysis showed that there were significant correlations among functional traits of H. tibetana leaves. Redundancy analysis (RDA) showed that soil water content (SWC), altitude (Alt) and soil organic carbon (SOC) had significant effects on the functional traits of H. tibetana leaves (p < 0.05).

Biocontrol potential of endophytic Trichoderma citrinoviride HT-1 against root rot of Rheum palmatum through both antagonistic effects and induced systemic resistance.

Some Trichoderma species have been used as biocontrol agents in agriculture. The effectiveness of T. citrinoviride HT-1, a beneficial endophyte isolated from Rheum palmatum root was explored for control of root rot and its mechanisms of induced systemic resistance. The results showed that the inhibition rate of F. oxysporum was 71.85% in dual culture. The fermentation metabolites (FM) of the T. citrinoviride HT-1 strain suppressed mycelial growth of F. oxysporum, recording an inhibition rate of 79.07%. Conidial suspensions of T. citrinoviride HT-1(1 × 107 spores/mL) can suppress the root rot of R. palmatum caused by F. oxysporum to a low disease index (17.60) and had significant control effects on root rot (72.53%). The activities of induced defense-related enzymes in R. palmatum plants were significantly increased following T. citrinoviride HT-1 treatment. The RT-PCR analysis of the defense-related genes showed that T. citrinoviride HT-1 can increase the defense response-related gene expression. This study has contributed to our understanding of the biocontrol potential of T. citrinoviride HT-1 and provided a theoretical basis for the application as a bio-fungicide.

The Bet-Hedging Strategies for Seedling Emergence of Calligonum mongolicum to Adapt to the Extreme Desert Environments in Northwestern China.

Calligonum mongolicum is a dominant native perennial shrub on sand dunes in arid deserts of northwestern China, and is therefore widely used in sand dune stabilization in these regions. However, it remains largely unknown how seedling emergence of C. mongolicum has adapted to unpredictable sand movement and extreme drought. Here we examined effects of seed burial depth, light intensity, and seed age on seedling emergence, and considered seed germination and seedling emergence strategies for the shrub's adaption to the desert environment. In our pot experiment, the optimum seeding depth for emergence of C. mongolicum was 2 cm, indicating that for germination and seedling emergence only moderate sand burial is required. Light intensity at the surface soil (0 cm) was important for seedling emergence, while there was no significant difference between 50 and 20% light flux density, at burial depths of 1 and 2 cm, indicating that C. mongolicum seeds had adapted to sand burial, while not exposure from sand erosion. We also found C. mongolicum seedlings emerged in spring and in late summer to early autumn. Meanwhile, seedling emergence percentage for 3-year-old seeds was similar to that of 1-year-old seeds, which meant that C. mongolicum seeds were well preserved under normal sand dune conditions, thus were capable of developing a persistent, but shallow soil seed-bank. These results indicated that germination and seedling emergence take a bet-hedging strategies to adapt to variable desert environments. Our study confirmed that C. mongolicum desert shrubs combine strategies in its adaption to arid and variable sand environments.

Factors influencing the natural regeneration of the pioneering shrub Calligonum mongolicum in sand dune stabilization plantations in arid deserts of northwest China.

Calligonum mongolicum is a successful pioneer shrub to combat desertification, which is widely used for vegetation restoration in the desert regions of northwest China. In order to reveal the limitations to natural regeneration of C. mongolicum by asexual and sexual reproduction, following the process of sand dune stabilization, we assessed clonal shoots, seedling emergence, soil seed bank density, and soil physical characteristics in mobile and stabilized sand dunes. Controlled field and pot experiments were also conducted to assess germination and seedling emergence in different dune soil types and seed burial depths. The population density of mature C. mongolicum was significantly different after sand dune stabilization. Juvenile density of C. mongolicm was much lower in stabilized sand dunes than mobile sand dune. There was no significant difference in soil seed bank density at three soil depths between mobile and stabilized sand dunes, while the emergence of seedlings in stabilized dunes was much lower than emergence in mobile dunes. There was no clonal propagation found in stabilized dunes, and very few C. mongolicum seedlings were established on stabilized sand dunes. Soil clay and silt content, air-filled porosity, and soil surface compaction were significantly changed from mobile sand dune to stabilized dunes. Seedling emergence of C. mongolicm was highly dependent on soil physical condition. These results indicated that changes in soil physical condition limited clonal propagation and seedling emergence of C. mongolicum in stabilized sand dunes. Seed bank density was not a limiting factor; however, poor seedling establishment limited C. mongolicum's further natural regeneration in stabilized sand dunes. Therefore, clonal propagation may be the most important mode for population expansion in mobile sand dunes. As a pioneer species C. mongolicum is well adapted to propagate in mobile sand dune conditions, it appears unlikely to survive naturally in stabilized sand dune plantations.

Impacts of Sand Burial and Wind Erosion on Regeneration and Growth of a Desert Clonal Shrub.

Sand burial and wind erosion caused by sand movement are common phenomena in desert environments, but the effects on clonal shrub have rarely been investigated. Here, we assessed how sand movements affect the population regeneration capacity of juvenile clonal fragments of the shrub Calligonum mongolicum growing in mobile desert sand dunes. We investigated the population status and natural regeneration capacity in three types of mobile dunes (heavy wind erosion, heavy sand burial and moderate sand burial). Clonal propagation of C. mongolicum was markedly different across sites. Moderate sand burial sites had the largest ramet density and bud number per unit length of rhizome, and the overwinter survival rate was significantly higher at sand burial sites than at wind erosion sites, suggesting that C. mongolicum may have well adapted to the moderate sand burial environment. We further examined the effects of clonal integration on clonal regeneration of this species. Physiological, biochemical and morphological characteristics of parent and daughter ramets growing in heterogeneous sandy habitats (sand burial or wind erosion) were measured. The results showed that being connected or severed from the maternal plant critically determined survival of daughter ramets on wind eroded rhizomes. When eroded rhizomes remained connected, the mother ramets had the highest chlorophyll a, b and a + b contents. However, both the mother plant and the daughter ramets undergoing erosion had higher proline and soluble protein levels than sand buried ramets. Meanwhile, the daughter ramets undergoing sand burial had higher photosynthetic rates (P n), chlorophyll fluorescence parameters (F m and F o), and phenotypic traits of assimilating shoots, i.e., node number, length and volume than wind-eroded ramets. However, significant differences with mother plants, whether connected or severed, were very limited. It was concluded that moderate sand burial environments promoted clonal reproduction and growth of C. mongolicum. Additionally, physiological integration with mother raments in favorable conditions can alleviate stress on daughter ramets exposed to wind erosion. This physiological effect may do not occur for sand buried daughter ramets. These survival strategies and phenotypic responses should be carefully considered in shrub and sand dune management in sand fixation plantations of C. mongolicum.

Changes in wind erosion over a 25-year restoration chronosequence on the south edge of the Tengger Desert, China: implications for preventing desertification.

Wind erosion is a primary cause of desertification as well as being a serious ecological problem in arid and semi-arid areas across the world. To determine mechanisms for restoring desertified lands, an unrestored shifting sand dune and three formerly shifting sand dunes (desertified lands) that had been enclosed and afforested for 5, 15, and 25 years were selected for evaluation on the south edge of the Tengger Desert, China. Based on sampling heights between 0.2 and 3 m, the critical threshold average wind speed was 6.5 m s-1 at 2 m where the sand transport rate was reduced from 285.9 kg m-2 h-1 on the unrestored dunes to 9.1 and 1.8 kg m-2 h-1 on the sites afforested and enclosed for 5 and 15 years, respectively. The percentage of wind eroded area was reduced from 99.9% on the unrestored dune to 94.5, 9.0, and 0.5% on the sites afforested and enclosed for 5, 15, and 25 years, respectively. Wind erosion was effectively reduced after 15 years. Although there were different driving factors for wind erosion mitigation on the different restoration stages, an increase in the vegetation cover, surface roughness, soil shear strength, soil clay content, organic matter, and reduction in the near-surface wind speed were the primary variables associated with the restoration chronosequence. We conclude that reducing the wind speed and developing a biological crust through vegetation restoration were the critical components for restoration of desertified land.

Long-Term Effects of Xerophytic Shrub Haloxylon ammodendron Plantations on Soil Properties and Vegetation Dynamics in Northwest China.

The xerophytic desert shrub Haloxylon ammodendron (C. A. Mey.) Bunge. is distributed naturally in Asian and African deserts, and is widely used for vegetation restoration in the desert regions of Northern China. However, there are limited long-term chrono-sequence studies on the impact of changed soil properties and vegetation dynamics following establishment of this shrub on mobile sand dunes. In Minqin County, Gansu Province, we investigated soil properties and herbaceous vegetation development of 10, 20, 30, 40, 50-year-old H. ammodendron plantations on mobile sand dunes. Soil sampling at two depths (0-5 and 5-20 cm) under the shrubs determined SOC, nutrition and soil physical characteristics. The results showed that: establishment of H. ammodendron had improved soil physio-chemical properties, increased thickness of soil crusts and coverage of biological soil crusts (BSCs), and promoted development of topsoil over an extended period of 5 decades. Soil texture and soil nutrition improved along the chrono-sequence according to three distinct phases: i) an initial fast development from 0 to 10 years, ii) a stabilizing phase from 10 to 30 years followed by iii) a relatively marked restoration development in 40 and 50-year-old plantations. Meanwhile, herbaceous community coverage also markedly increased in 30-year-old plantations. However, both soil and vegetation restoration were very slow due to low annual precipitation in Minqin county compared to other Northern China sand afforestation sites. Canonical Correspondence Analysis results demonstrated that herbaceous plant development was closely associated with changes in soil texture (increased clay and silt percentage) and availability of soil nutrients. Thus our results indicated that selection of the long-lived shrub H. ammodendron is an essential and effective tool in arid desert re-vegetation.

[Mass spectrography analysis of differential proteome in childhood TEL/AML1-positive acute lymphoblastic leukemia].

The study was aimed to establish differential proteomic expression analysis of two dimensional electrophoresis and mass spectrography, and to further explore the mechanisms of nosogenesis in childhood TEL/AML1(+) acute lymphoblastic leukemia. On the basis of initial leukocyte count and prognostic factors, patients enrolled in this study were divided into three risk groups (early relapse, high leukocyte count and standard risk groups). The proteins of leukemic cells from patients at diagnosis were separated by two-dimensional gel electrophoresis. Spot detection, quantification and alignment were performed with the PDQuest 7.3.0 image analysis software. Differentially expressed spots were analyzed by mass spectrometry for peptide mass finger (PMF) data. The results showed that the significant difference of protein expression profile existed in 3 groups of childhood TEL/AML1-positive acute lymphoblastic leukemia. Compared with the high leukocyte count and standard risk groups, 71 protein spots disappeared; 93 new protein spots were found; 37 protein spot expressions were up-regulated; 23 protein spots were down-regulated in early relapse group. Compared the high leukocyte count group, 6 protein spots disappeared, 56 new protein spots were found, 7 protein spot expression were up-regulated, 19 protein spot expressions were down-regulated in standard risk group. The identification of 40 differential protein spots by using mass spectrometry revealed some proteins in 3 groups such as tropomyosin, lactotransferrin, lactate dehydrogenase A, CRMP1 protein, alphaenolase, AKR1B1, calnexin precursor, heat shock protein (HSP86/HSP89/HSP90), annexin VI, G22P1 and so on. Among them the HSP86/HSP89/HSP90 highly expressed only in early reapse group, the lactotransferrin, alphenolase and G22P1 expressions were up-regulated in early relapse group. It is concluded that the protein expression in early relapse group is significant different from the others. Some proteins may be further used in research on leukemia mechanisms. In addition, these analyses may promote the identification of new targets for individualized treatment approaches.

[Analysis of cells in Tel/aml-1 positive childhood acute lymphoblastic leukemia by two-dimensional gel electrophoresis].

This study was aimed to establish the protein expression profile of tel/aml-1+ childhood acute lymphoblastic leukemia (ALL) with different prognoses by two-dimensional polyacrylamide gel electrophoresis and explore the nosogenesis of tel/aml-1+ ALL childhood. On the basis of leukocyte count at new diagnosis, early reaction to therapy and clinical prognosis, the patients with tel/aml-1+ ALL were divided into 3 groups: early relapse group, high leukocyte count group and standard risk group. The bone marrow was taken from newly diagnosed patients for isolating protein, then the protein in leukemia cells was isolated by two-dimensional polyacrylamide gel electrophoresis, the image analysis of differential protein among 3 groups was carried out by using the PDQuest 7.3.0 image analysis software. The results showed that there were significant difference of protein expression profile among 3 groups. As compared with high leukocyte count and standard risk groups, 71 protein spots disappeared, 93 new protein spots appeared, the expression of 37 protein spots was up-regulated and the expression of 23 protein spots was down-regulated in early relapse group. As compared with high leukocyte count group, 6 protein spots disappeared, 56 new protein spots appeared, the expression of 7 protein spots was up-regulated, and expression of 19 protein spots was down-regulated in standard risk group. It is concluded that the protein expression profile in early relapse group is significantly different from other groups. Some proteins may play an important role in pathogenesis of childhood tel/aml-1+ ALL, and probably become new molecular indicators and targets for individualized treatment.

Copper deficiency in yaks on pasture in western China.

The clinical signs of a disorder in yaks (Bos grunniens), known locally as "swayback ailment," in the Qing Hai-Tibetan Plateau are described. The purpose of this study is to investigate the possibility that swayback ailment is iron (Fe)-induced copper (Cu) deficiency. The mean concentrations of Cu in soil and forage from affected areas and unaffected areas are similar and within the normal ranges. The mean concentrations of Cu in blood and hair from the affected yaks was significantly lower (P < 0.01) than that in unaffected yaks. The mean concentrations of Fe in soil and forage were significantly higher (P < 0.01) in affected than in unaffected areas. Affected yaks showed a hypochromic microcytic anemia and a low level of ceruloplasmin. Oral administration of copper sulphate prevented and cured the disease. We conclude that "swayback disorder" of yaks is caused by secondary Cu deficiency, mainly due to the high Fe content in forage.