异源表达棉花S-腺苷甲硫氨酸脱羧酶(Gh SAMDC1)基因提高了拟南芥抗盐能力

以转GhSAMDC1基因拟南芥研究了过量表达GhSAMDC1基因对拟南芥幼苗抗盐能力的影响,以及内源多胺、过氧化氢(H2O2)、丙二醛(MDA)、叶绿素含量(Chl)、离子渗透率、抗氧化酶(SOD、CAT、POD)活性和表达量在盐胁迫下的变化。结果表明,过量表达GhSAMDC1基因能够减少拟南芥内源腐胺(Put)含量,增加亚精胺(Spd)和精胺(Spm)含量。盐胁迫下,转基因株系亚精胺合酶(AtSPDS1、AtSPDS2)和精胺合酶(AtSPMS)基因表达量明显高于野生型,Spd和Spm含量进一步增加,H2O2、MDA、Chl以及离子渗透率显著降低;与野生型相比,过氧化物酶(POD)活力无明显差异,但超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活力明显增加,其表达水平与活力变化趋势基本一致。因此,盐胁迫下,GhSAMDC1基因通过提高Spd和Spm合成相关基因的表达,增加了转基因株系Spd和Spm含量,Spd和Spm直接或间接提高抗氧化系统相关酶的活力,通过清除H2O2等活性氧的方式提高拟南芥的抗盐能力。     

SCAR and CAPS markers flanking the Brassica oleracea L. Pp523 downy mildew resistance locus demarcate a genomic region syntenic to the top arm end of Arabidopsis thaliana L. chromosome 1

We recently mapped the Pp523 locus that includes a single, dominant gene conferring resistance to downy mildew expressed in adult plants to a 75.1 cm long linkage group on a genetic linkage map of Brassica oleracea L. More recently, we identified a new AFLP marker 2.8 cm downstream from the resistance gene. The five DNA markers within an 8.5 cm region encompassing the Pp523 gene were cloned and sequenced. Three of these markers were transformed into SCARs (sequence characterised amplified regions), however, two among them were monomorphic and were analysed as CAPS (cleaved amplified polymorphic sequence) markers among the mapping population. Searched against genomic databases, the five B. oleracea DNA-marker sequences matched Arabidopsis thaliana L. gene sequences that delimit a conserved syntenic region in the top arm end of chromosome 1 of this last species. Considering the close genetic relatedness between both species, the information on this specific genomic region in A. thaliana is particularly useful for the construction of a fine-scale map of the corresponding genomic region in B. oleracea. The identified SCAR and CAPS markers can be used for marker assisted selection (MAS) in breeding programs aimed at the introgression of the Pp523 resistance locus, allowing the reliable indirect identification of plants harbouring the resistance gene with a margin of error of approximately six in ten-thousand selected plants.     

马铃薯StIgt基因家族的鉴定及其对干旱胁迫的响应分析

干旱胁迫是影响马铃薯产量和品质的主要非生物胁迫因素之一。马铃薯在抵御干旱胁迫的过程中,根系的生长发育和构型分布发挥着重要作用。Igt基因家族是普遍存在于植物中的一类功能基因,在调控植物根系构型和提高植株抗逆性等方面效果显著。本研究以马铃薯双单倍体‘DM-v4.03’高质量基因组为参考,在全基因组范围内分析鉴定了StIgt基因家族的成员,并采用多种生物信息学软件对其进行了系统进化树构建、染色体定位、保守蛋白结构域、基因结构和顺式元件预测。同时,利用本课题组前期对马铃薯四倍体品系在不同干旱条件下的转录组测序结果,分析了StIgts响应干旱胁迫的表达谱。结果表明,在马铃薯中共鉴定获得10个StIgt家族成员,其中StIgt1由本课题组前期克隆获得。除StIgt1位置信息不明外,其余基因不均匀地分布在1、2、5、7、10和11号染色体上。StIgt家族蛋白长度为110~283个氨基酸,分子量介于13.136~32.542 kD之间,预测等电点为3.82~9.86。系统进化树分析发现,该基因家族可分为3个亚族,亚族间的基因结构、蛋白保守域和顺式作用元件差别明显。干旱胁迫下的表达谱分析表明,StIgt6、StIgt7、StIgt9和StIgt10响应早期干旱胁迫,在干旱2 h时即迅速上调表达。这些结果为阐明StIgt基因家族的进化关系和进一步研究其成员的功能特性提供了理论基础。     

拟南芥RBCS-1A基因受光调节表达模式及其启动子遗传转化应用评价

RBCS编码光合碳同化关键酶核酮糖1,5-二磷酸羧化酶/加氧酶的小亚基, 是控制植物光合作用的重要基因之一。本研究利用实时荧光定量PCR技术分析拟南芥RBCS-1A受光调节表达模式, 结果表明, AtRBCS-1A表达受光诱导, 同时具有组织表达特异性; 运用生物信息学手段分析发现, 该基因启动子序列中存在多个参与光应答的顺式作用元件; 采用PCR技术从拟南芥基因组中分离到长度为1 691 bp的AtRBCS-1A启动子片段, 将该片段与GUS报告基因融合构建植物表达载体并转化野生型拟南芥, 对获得的转基因植株进行GUS染色, 结果显示, AtRBCS-1A启动子是光诱导型和组织特异型启动子。以上结果初步证明, AtRBCS-1A启动子应用于植物遗传转化切实可行, 具有重要应用价值。     

Fine mapping of Rf2, a major locus controlling pollen fertility restoration in sorghum A1 cytoplasm,encodes a PPR gene and its validation through expression analysis

Sorghum is one of the pioneering cereal crops where cytoplasmic male sterility (CMS) was successfully exploited for mass production of F₁ hybrid seed. Mapping genes for fertility restoration (Rf) is an important aspect of understanding the molecular basis of fertility restoration in crop plants. In this study, we fine‐mapped a fertility restoration locus, Rf2 of sorghum reported earlier (Jordan, Mace, Henzell, Klein, & Klein, 2010 ), involving two F₂ populations (296A × RS29 and 296A × DSV1) and newly developed SSR markers delimited Rf2 locus to 10.32‐kb region on chromosome 2. The Rf2 locus was tightly linked with two new SSRs, MS‐SB02‐3460 (0.14 cM) and MS‐SB02‐3466 (0.75 cM) on both sides, and hosted only one gene (Sobic.002G057050) of PPR gene family. Another new SSR marker developed in the study, MS‐SB02‐37912, forms the part of PPR gene and could act as a perfect marker in marker‐assisted breeding for fertility restoration involving Rf2 in sorghum breeding. The strong involvement of Sobic.002G057050 gene in fertility restoration was supported through RNA expression analysis.