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Pinus massoniaia Lamb has gained more and more attention as the most important tree species for timber and forestation in South China. Gene expression studies are of great importance to identify new and elite cultivars. Real-time quantitative PCR, a highly sensitive and specific method, is commonly used in the analysis of gene expression. The appropriate reference genes must be employed to normalize the calculation program for ascertaining repeatable and significant results. Herein, eleven housekeeping genes were evaluated during different stages of P. massoniana post nematode inoculation in this study. Three statistical approaches such as geNorm, NormFinder and BestKeeper were selected to analyze the stability of candidate genes. The results indicated that U2af and β-TUB were the most stable reference genes. These two genes could be used for the normalization in most of the experiments of P. massoniana, while Histone and AK were the least stable ones. In addition, EF expressed at the lowest average Ct value was the most abundant candidate gene. As an important gene associated with defense mechanisms, ABC transporter was analyzed by qRT-PCR, and the results were used to confirm the reliability of two genes. The selected reference genes in the present study will be conducive to future gene expression normalized by qRT-PCR in P. massoniana. [ABSTRACT FROM AUTHOR]

Maize rough dwarf disease caused by Rice black-streaked dwarf virus (RBSDV) is the most important disease of maize in China. Although deploying disease resistant hybrids would be the most effective way to control the disease, development of resistant hybrids has been limited by virus transmission rates that are too low for effective screening. An efficient inoculation technique for RBSDV was developed using Laodelphax striatellus Fallen, in which a virus-free planthopper colony was developed and viruliferous planthoppers were obtained by allowing a 3- to 4-day acquisition access period on RBSDV-infected wheat plants. Planthoppers were then allowed a 25- to 28-day latent period on wheat seedlings followed by a 3-day inoculation access period on two-to-three-leaf stage maize seedlings. By 35 days postinoculation, susceptible hybrid 'Zhengdan 958', inbred lines of 'Ye 107' and 'Ye 478' plants showed 100% RBSDV infection with symptoms of stunting plants, darkening leaves and white waxy swellings on underside of leaves. At tasseling stage, average disease indices were from 96.4 to 100.0%. Enzyme-linked immunosorbent assays were correlated with the presence of symptoms. The high efficiency of RBSDV transmission obtained using this technique provides a reliable procedure to screen for RBSDV resistance in maize. [ABSTRACT FROM AUTHOR]

Abstract: Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is a serious disease worldwide, and a problem in China, especially in Sichuan Province, where it causes partial or total loss of grain yield on susceptible varieties when climatic conditions are favorable. In this study, we clarified ways and areas of the over-summering of this fungus, and provided information for control of the disease in Sichuan Province. We observed cleistothecial survival under a variety of different storage conditions both indoors and outdoors. Cleistothecia in humid conditions completely died by mid-July; those in dry conditions maintained a 40% survival rate into the autumn. Cleistothecia were not only able to survive until fall, but also to produce ascospores as initial inoculums for autumn-sown wheat. Field inoculation experiments using ascospores and conidia at different altitudes in Ya''an, Yibin, and Bazhong demonstrated that B. graminis f. sp. tritici is able to over-summer at an altitude of 595 m and above in Sichuan Province. Volunteer wheat plants are abundant in these areas. Through systematic monitoring, volunteer wheat plants were found to be heavily infected during the summer months, providing an inoculation bridge to the fall planting season. The type of crops following wheat also had an important influence on the over-summering of the fungus; high-shade corn was more favorable to volunteer wheat survival and the occurrence of powdery mildew than short-shade soybeans. The most effective strategy for reducing inoculation would be to eliminate the remaining wheat straws and the volunteer wheat before fall seeding. [Copyright &y& Elsevier]

Dwarf bunt caused by Tilletia contraversa is a disease of winter wheat that has a limited geographic distribution due to specific winter climate requirements. The pathogen is listed as a quarantine organism by several countries that may have wheat production areas with inadequate or marginal climate for the disease—in particular the People's Republic of China. Field experiments were conducted in the United States in an area of Kansas that is a climatic analog to the northern winter wheat areas of China to evaluate the risk of disease introduction into such areas. The soil surface of four replicate 2.8 × 9.75 m plots, planted with a highly susceptible cultivar, was inoculated with six teliospore concentrations ranging from 0.88 to 88,400 teliospores/cm2. A single initial inoculation was done in each of three nurseries planted during separate seasons followed by examination for disease for 4 to 6 years afterward. Any diseased spikes produced were crushed and returned to the plots where they were produced. One nursery had no disease during all six seasons. In two nurseries, the disease was induced at trace levels at the three highest inoculation rates. Disease carryover to the second year occurred during one year in one nursery in plots at the highest inoculation rate, but no disease occurred the following three seasons. A duplicate nursery planted in a disease conducive area in Utah demonstrated that the highest rate of inoculum used in the experiments was sufficient to cause almost 100% infection. This study demonstrated that in an area with marginal climatic conditions it was possible to induce transient trace levels of dwarf bunt, but the disease was not established even with a highly susceptible cultivar and high levels of inoculum. Our results support the conclusions of the 1999 Agreement on U.S.-China Agricultural Cooperation which set a tolerance for teliospores in grain, and supports the Risk Assessment Model for Importation of United States Milling Wheat Containing T. contraversa. [ABSTRACT FROM AUTHOR]

[Objective] The paper was to determine the resistance level of the tried and pre-examination wheat cultivars against powdery mildew in Anhui Province of China. [Method] By using artificial inoculation and identification method in fields, the resistance of wheat cultivars was identified in consecutive three years from 2010 to 2012. [Result] The highly susceptible (HS) cultivar accounted for 30%, 42% and 11% of total tested cultivars in the years of 2010, 2011 and 2012, respectively; moderately susceptible (MS) cultivar accounted for 53% of total tested cultivars in 2010, which accounted for 47% and 57% in 2011 and 2012, respectively; moderately resistant (MR) cultivar accounted for 17% of total tested cultivars in 2010, which accounted for 11% and 32% in 2011 and 2012, respectively. [Conclusion] The paper can guide breeding direction, and also provide scientific basis for variety approval. [ABSTRACT FROM AUTHOR]