EMS诱变花生珍珠红1号创制优良新种质

为创制花生优良新种质,以花生品种珍珠红1号的干种子为材料,采用浸泡法开展甲基磺酸乙酯(EMS)诱变研究。结果表明,以半致死剂量为选择标准,适宜诱变条件为0.8%EMS处理10 h;筛选获得9个优良M₅突变系,其中4个表现出产量高、品质优、综合性状优良等特点。上述4个M₅突变系干荚果产量较对照(珍珠红1号)增加10.93%～26.78%,出仁率均高于对照;在品质方面,诱珍珠红1号2Ⅱ/19油酸含量为56.68%、油酸/亚油酸比值(O/L)为1.92,分别较对照提高8.44个百分点和0.57;诱珍珠红1号2Ⅲ/8亚油酸含量为39.05%,较对照提高3.28个百分点;诱珍珠红1号2Ⅲ/10粗脂肪含量为54.52%,较对照提高1.50个百分点;诱珍珠红1号3Ⅰ/8油酸含量为53.70%、O/L为1.71,分别较对照提高5.46个百分点和0.36。ISSR分子标记结果表明,9个优良M₄突变系与珍珠红1号在分子水平上均存在明显差异,突变系之间在分子水平上也存在明显差异。本研究结果为花生遗传改良和功能基因研究提供了优良的新种质,为花生...     

春性甘蓝型油菜EMS突变体库的构建与筛选

创制突变体库是甘蓝型油菜品种选育和重要性状遗传解析的重要基础。春性甘蓝型油菜开花不需漫长的春化过程,生育期短,在创制突变体库方面具有独特优势。本研究采用甲基磺酸乙酯（EMS）诱变春性油菜862种子,以构建春性油菜EMS诱变突变体资源库。通过比较8种不同浓度EMS（0~1.4%,间隔0.2%）对发芽率的影响,最终确定使用0.8%的EMS作为最佳处理浓度,发芽率为37.2%。田间种植筛选与表型统计初步鉴定了M2代1823个单株的形态学性状,突变频率为3.91%,主要包括叶色、叶形、株高、株型、角果长短、种粒大小、种皮颜色、种子含油量以及其它性状变异等,突变类型十分丰富。该突变体库的构建为油菜功能基因组学研究和分子育种提供表型多样的种质资源。     

EMS诱变对刺梨种子出苗及早期生长性状的影响

以刺梨品种‘贵农5号’的种子为试材,种皮经砂纸磨损后用浓度为0.1%、0.3%、0.6%、0.9%的甲基磺/酸乙酯(EMS)分别浸种处理12h和24h后播种,研究了出苗率、成苗率并观测幼苗早期生长表型性状,以期筛选出最适诱变剂量和处理时间,为后期构建大量刺梨EMS突变群体奠定技术基础。结果表明:0.1%~0.3%的低浓度EMS处理能提高种子的出苗率和成苗率,但随着EMS浓度升高或处理时间的延长,出苗率和成苗率均显著降低,当浓度升至0.9%处理12h或0.6%处理24h时其种子死亡率为100%。成活幼苗的生长性状可在株高、株型、叶型、分枝等方面表现出不同的表型变异,且在一定浓度范围内其变异率随着处理浓度增加而增加。综合考虑成苗率和表型变异率等数据,筛选得出0.3%EMS浸种12h为刺梨种子突变的适宜剂量条件。     

Variations in chlorophyll content,stomatal conductance,and photosynthesis in Setaria EMS mutants

Chlorophyll (Chl) content, especially Chl b content, and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n). Setaria italica, a diploid C₄ panicoid species with a simple genome and high transformation efficiency, has been widely accepted as a model in photosynthesis and drought-tolerance research. The current study characterized Chl content, G_s, and P_n of 48 Setaria mutants induced by ethyl methanesulfonate. A total of 24, 34, and 35 mutants had significant variations in Chl content, G_s, and P_n, respectively. Correlation analysis showed a positive correlation between increased G_s and increased P_n, and a weak correlation between decreased Chl b content and decreased P_n was also found. Remarkably, two mutants behaved with significantly decreased Chl b content but increased P_n compared to Yugu 1. Seven mutants behaved with significantly decreased G_s but did not decrease P_n compared to Yugu 1. The current study thus identified various genetic lines, further exploration of which would be beneficial to elucidate the relationship between Chl content, G_s, and P_n and the mechanism underlying why C₄ species are efficient at photosynthesis and water saving.     

A single nucleotide substitution in the MATE transporter gene regulates plastochron and the many noded dwarf phenotype in barley (Hordeum vulgare L.)

In higher plants, the shoot apical meristem produces lateral organs in a regular spacing (phyllotaxy) and timing (plastochron). The molecular analysis of mutants associated with phyllotaxy and plastochron would increase our understanding of the mechanism of shoot architecture formation. In this study, we identified mutant mnd8^ynp5 that shows an increased rate of leaf emergence and a larger number of nodes in combination with a dwarfed growth habit from an EMS-treated population of the elite barley cultivar Yangnongpi 5. Using a map-based cloning strategy, the mnd8 gene was narrowed down to a 6.7-kb genomic interval on the long arm of chromosome 5H. Sequence analysis revealed that a C to T single-nucleotide mutation occurred at the first exon (position 953) of HORVU5Hr1G118820, leading to an alanine (Ala) to valine (Val) substitution at the 318th amino acid site. Next, HORVU5Hr1G118820 was defined as the candidate gene of MND8 encoding 514 amino acids and containing two multidrug and toxic compound extrusion (MATE) domains. It is highly homologous to maize Bige1 and has a conserved function in the regulation of plant development by controlling the leaf initiation rate. Examination of modern barely varieties showed that Hap-1 was the dominant haplotype and was selected in barley breeding around the world. Collectively, our results indicated that mnd8^ynp5 is a novel allele of the HORVU5Hr1G118820 gene that is possibly responsible for the shortened plastochron and many noded dwarf phenotype in barley.