Transcriptomics and iTRAQ-proteomics analyses provide novel insights into the defense mechanism of black shank disease in tobacco.

Black shank disease caused by Phytophthora nicotianae is one of the most important diseases in tobacco worldwide and can result in a devastating loss in tobacco cultivation. Many efforts have been carried out to identify the chromosome segment from Nicotiana plumbaginifolia containing a resistance locus carrying a gene named Php; however, the Php gene has not been cloned, and knowledge of the potential mechanism of the Php gene in the resistant lines is limited. To further characterize the resistance mechanism of the Php gene, we first used the resistant line "RBST" and the susceptible cultivar "Honghuadajinyuan" (HD) to obtain the near-isogenic line RBS89 containing the Php gene from RBST. RBS89 showed high resistance to black shank disease. Transcriptomic and iTRAQ analyses were applied to explore the potential defense mechanisms in RBS89 plants in comparison with HD plants with or without inoculation. Many differentially expressed genes (DEGs) and proteins were identified, and some pathogenesis-related (PR) proteins were extensively abundant in the RBS89 plants when compared with the HD plants in response to black shank disease. Importantly, overexpression of the PR gene NtPR-1B in HD plants improved the resistance of tobacco plants to black shank disease, indicating that NtPR-1B and Php genes might have similar roles in protecting tobacco from black shank disease. However, the relationship between NtPR-1B and Php genes requires further analysis. Therefore, our study provides valuable information for breeding tobacco cultivars with black shank disease resistance and sheds light on the defense mechanism of black shank disease in tobacco for enhancing Phytophthora resistance in other Solanaceae crops.

Transcriptomic profile of tobacco in response to Phytophthora nicotianae infection.

Black shank, caused by Phytophthora nicotianae (P. nicotianae), is a serious disease of cultivated tobacco (Nicotiana tabacum) worldwide. The interactions between tobacco and P. nicotianae are complex and the outcomes of the interactions depend on the tobacco genotype, P. nicotianae strain, and environmental conditions. In this study, we used RNA-sequencing (RNA-Seq) to investigate and compare transcriptional changes in the stems of tobacco upon inoculation with P. nicotianae strain race 0. We used two tobacco varieties: RBST (named from resistance to black shank and tobacco mosaic virus), which was resistant to the P. nicotianae strain race 0, and Honghuadajinyuan (HD), which was susceptible to P. nicotianae race 0. Samples were collected 12 and 72-hour post inoculation (hpi). Analysis of differentially expressed genes (DEGs) and significantly enriched GO terms indicated that several basic defense mechanisms were suppressed in both varieties, which included response to wounding (GO: 0009611), and defense response to fungus (GO: 0050832). We also found some genes that may especially be related to mechanisms of resistance in RBST, such as the one encoding a chitinase. These results will provide a valuable resource for understanding the interactions between P. nicotianae and tobacco plants.

[An Identification Study on Field-Derived Spectra of Grassland Combustibles and Soil Based on Fractal Theory].

Grassland fire disaster is an important influence factor to grassland ecological system in China. Therefore, it is crucial to study on the monitoring, prediction and management of grassland fire. Remote Sensing (RS) provides detailed data and saves a lot of manpower, material resources and financial resources on the research of grassland fire. However, it is difficult to identify the grassland fuel and soil with Remote Sensing. In this paper, we introduced fractal into the spectral analyses of the field-derived spectra (FDS) of grassland fuel and soil to solve the problem above. The study area laid on the Westward of Changling, Jinlin province, China. Study subjects included soil and dominant species: Leymus chinensis, Reed, Chloris virgate, Kalimeris integrifolia and Artemisia mongolica. FDS of study subjects were measured with ASD FS3 and continuums of FDS were calculated by Matlab 2010. Meanwhile, Box-counting values of FDS and continuums were calculated by Matlab 2010. According to the spectral and continuum analysis, it is difficult to identify soil, Leymus chinensis, Reed, Chloris virgate, and Artemisia mongolica because of the similar spectral curves. However, the Artemisia mongolica can be identified for the strong reflection. For typical fractal characteristics of FDS and continuum, clustering analyses of study subjects were done according to box-counting values of FDS and continuum. The results of clustering analyses show that Box-counting values of FDS and continuum are important indexes to identify the study subjects. This study provides a new thought to identity the grassland combustibles and soil with Remote Sensing.

[Mapping of Sanming dominant genic male sterility gene in rice].

The mutant of "Sanming Dominant Genic Male Sterile Rice" was found from an F2 population of cross "SE2lS/Basmati370" by Sanming Institute of Agricultural Science in 2001. It has proven that the male sterility of this mutant is controlled by a dominant gene (named as SMS). By multiple backcrosses, this dominant male sterile allele was introduced into the genetic background of an indica rice cultivar Jiafuzhan (which was known as Jiabuyu). In order to map SMS, a mapping population was constructed by crossing Jiabuyu with a japonica cultivar Nipponbare and further crossing the F1 with Jiafuzhan. By bulked segregant analysis and linkage analysis using SSR and INDEL markers, SMS was mapped to a 99 kb interval between INDEL markers ZM30 and ZM9 on chromosome 8. This result will facilitate cloning of SMS.

[Ecological security assessment of Baishan City in Jilin Province based on DPSIR].

This paper explored the main driving forces and stresses contributing to the eco-environmental changes of Baishan City in Jilin Province, through the analysis of the ecological security problems in the City. The framework of DPSIR was applied to establish an ecological security assessment index system, and further, to create an ecological security assessment model suitable for mountain areas. By using the 1989, 1999, and 2006 TM images, and in combining with the DEM data and field survey data, the interpretation of the land cover in Baishan City was conducted, and the landscape classification was carried out. With the support of Fragstats, the important ecological indicators were extracted. Then, the situations of ecological security in various districts and counties of Baishan City were assessed. The results indicated that there was an obvious regional difference in the ecological security of Baishan City, with a deteriorating trend of the overall ecological security situation. Human activities had deeper influence on the land cover pattern and species habitat distribution, and even, became the main driving force of the pattern changes in ecological security.