Complete chloroplast genome sequence and phylogenetic analysis of winter oil rapeseed (Brassica rapa L.).

Winter oil rapeseed '18 R-1' (Brassica rapa L.) is a new variety that can survive in northern China where the extreme low temperature is -20 °C to -32 °C. It is different from traditional B. rapa and Brassica napus. In this study, the complete chloroplast (cp) genome of '18 R-1' was sequenced and analyzed to assess the genetic relationship. The size of cp genome is 153,494 bp, including one large single copy (LSC) region of 83,280 bp and one small single copy (SSC) region of 17,776 bp, separated by two inverted repeat (IR) regions of 26,219 bp. The GC content of the whole genome is 36.35%, while those of LSC, SSC, and IR are 34.12%, 29.20%, and 42.32%, respectively. The cp genome encodes 132 genes, including 87 protein-coding genes, eight rRNA genes, and 37 tRNA genes. In repeat structure analysis, 288 simple sequence repeats (SSRs) were identified. Cp genome of '18 R-1' was closely related to Brassica chinensis, B. rapa and Brassica pekinesis.

[Effects of diverse stresses on gene expression and enzyme activity of glutathione reductase in Brassica campestris.] / é€†å¢ƒèƒè¿«å¯¹æ²¹èœè°·èƒ±ç”˜è‚½è¿˜åŽŸé ¶åŸºå› è¡¨è¾¾åŠå ¶é ¶æ´»æ€§çš„å½±å“.

A novel glutathione reductase gene (GR2) was isolated from Brassica campestris Longyou 6 by rapid isolation of cDNA ends (RACE). The full-length of cDNA of GR2 was 2073 bp, with an open reading frame (ORF) of 1692 bp. GR2 encoded a protein of 563 amino acids with a deduced molecular mass of about 60.7 kDa and an isoelectric point of 7.9. The real-time quantitative PCR results showed that GR2 was expressed in the roots, stems and leaves in B. campestris, among which the expression of GR2 in leaves was the highest. The transcript levels of GR1 and GR2, and the enzyme activity of glutathione reductase (GR) increased in response to cold temperature, high temperature, drought stress, and salt stress. The results suggested that GR played an important role in coping with diverse stresses in B. campestris. When abscisic acid (ABA) pretreatment was applied before cold temperature, high temperature, drought stress, salt stress, the expression levels of GR1and GR2, and the activity level of GR all significantly increased compared with the single stress, which indicated that ABA could induce GR1 and GR2 gene transcription and GR activity. However, when MAPKK inhibitor (U0126) pretreatment was applied before the above stresses, the expression levels of GR1and GR2 and the activity level of GR significantly decreased compared with the single stress suggesting that U0126 inhibited GR1 and GR2 gene transcription and GR activity.

[Safe wintering and economic and ecological benefit of winter rapeseed in dry and cold areas of northern China].

The purpose of this study was to realize the security of safe wintering of winter rapeseed in dry and cold regions of northern China. Experiments were conducted with 18 winter rapeseed (Brassica campestris) varieties at 57 sites from 2008 to 2013 to statistically analyze the wintering rate variation of different varieties in dry and cold regions of northern China. The results showed that, the wintering rate varied from 70% to 90% during the study period in different regions, which had no significant difference between different years and varieties, and had high stability and remarkable economic benefit. With Tianshui as a starting point of winter rapeseed planting, the wintering-safe regions included all Gansu Province , the south of Lasa and Linzhi of Xizang, the east of Minhe of Qinghai, up to Urumqi and Baicheng, and the south of Aletai, Tacheng, the east of Kashi of Xinjiang, it also included the regions along Yellow River eastward to Ningxia, the south of Linhe of Inner Mongolia, the north of Shaanxi, the vicinage of Qixian in Shanxi, Daming in Hebei, Tianjin, Beijing, the north of Weifang of Shandong, the south of Huludao of Liaoning and Yanbian of Jilin. Longyou 6, Longyou 7, Longyou 8 and Longyou 9 were the wintering-safe B. rapa varieties.

[Ecological benefits of planting winter rapeseed in western China].

To evaluate the ecological benefits of popularizing winter rapeseed planting in western China, a wind tunnel simulation test was conducted with four kinds of farmland surface, i.e., winter rapeseed, winter wheat, wheat stubble, and bare field just after spring sowing, collected from west Gansu in April. The results showed that winter rapeseed surface had a roughness of 4.08 cm and a threshold wind velocity as high as 14 m x s(-1), being more effective in blown sand control than the other three surfaces. Under the same experimental conditions, the wind erosion modulus and sand transportation rate of winter rapeseed surface were only 4.1% and 485% of those of the bare field just after spring sowing, and the losses of soil organic matter, alkali-hydrolyzed N, available P and K, catalase, urease, alkaline phosphatase, invertase, and microbes of winter rapeseed surface due to wind erosion were only 1.4%, 5.1%, 1.6%, 2.7%, 9.7%, 3.6%, 6.3%, 6.7% and 1.5% of those of the bare field, respectively. It was suggested that popularizing winter rapeseed planting in west China could control wind erosion, retain soil water and nutrients, increase multicropping index, and improve economic benefits of farmland. In addition, it could benefit the regional desertification control and ecological environment improvement.