Secondary seed dormancy(SSD)is responsible for volunteer plants in canola fields,which causes a series of problems in canola production and serves as an important trait for the environmental safety assessment of transgenic canola.A canola cultivar with strong SSD was used to establish insight into seed transcriptomes in its secondarily dormant seeds and control seeds without dormancy by RNA-seq analysis,aiming to determine the molecular ecological characterizations of SSD.A dataset(more than 4 Gb)of valid sequences was obtained from each sample,which was combined to carry out the de novo assembling.The assembled sequences consisted of 314,261fragments with length[100 bp,including 29,740 long transcripts of length C 500 bp.Functional annotation indicated that 1,641 long transcripts could be categorized into 24 cluster of orthologous groups of proteins(COGs)and 16,515 transcripts were linked to 2,648 gene ontology(GO)terms.There were 452 long transcripts with significantly different expression identified by a threshold of[2-fold expression change(P\0.001)between samples,among which 343 transcripts were unambiguously homologous to Arabidopsis genes.The plant hormones abscisic acid and gibberellins were known as the pivotal regulators of seed dormancy and germination.Although genes responsible for either biosynthesis or signaling of each hormone could be widely verified from the SSD transcriptome,theirs expression evidences failed to correlate with the induction of SSD.Based on the enriched terms of gene ontology and KEGG orthology,as well as the expression models of candidate genes of SSD,we proposed that fatty acid metabolism might implicate in SSD in canola.The information reported here may play a significant role in further understanding of environmental safety assessment of SSD in transgenic canola.
针对成熟油菜次生休眠种子富含多糖和多酚、老健组织部分富含RNA酶、生理活性低等特点,通过选用RNAplant plus reagent植物总RNA提取试剂,添加β-巯基乙醇抑制RNA酶活性、防止酚类物质氧化,应用醋酸钠去除多糖类物质对RNA的影响,以及缩短抽提时间等措施,建立成熟油菜次生休眠种子RNA的快速高效提取方法。结果表明:采用本方法提取的RNA D260nm/D280nm为1.92～2.05,28SrRNA和18SrRNA条带清晰而完整,且无明显降解,可以应用于后续的mRNA分离、建库和高通量转录组测序。
The isolation distance required for field trials of genetically modified (GM) rapeseed varies widely worldwide, with a 50-400 m distance in most nations contrasting with a minimum 1000-m isolation distance in China. The goal of this study was to evaluate the relevance of current regulations in China regarding the isolation distance needed for GM rapeseed trials. A pollen flow experiment was conducted based on the design of concentric circles, with the GM plants in a 20-m diameter circle at the centre, surrounded by non-GM plants to a distance 60 m from the perimeter of the circle containing GM plants. The rate of pollen flow was the highest at the isolation distance of 0.5 m, where it ranged from 2.3091% to 2.6711%. The general pattern of the pollen flow rate (y) with distance (x) was well described by the equation y = 1.3936x-0.9136 (R 2 = 0.9950). The long-distance pollen flow tested at the isolation distance of 800 m was 0.0018%, which agrees with the theoretical prediction. The results suggested that 300 m, rather than 1000 m, is a reasonable distance to ensure a tolerable threshold of pollen flow (less than 0.01%) under conditions of winter rapeseed production in China.
