【作者】 刘亚西；

【导师】 郑有良； 魏育明； 刘春吉；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2010， 博士

【摘要】 麦类作物包括小麦、大麦、燕麦、黑麦和小黑麦。其中小麦(Triticum aestivum L.)是我国乃至全世界最重要的粮食作物之一,和水稻、玉米一起并称世界三大粮食作物,其种植面积和产量均居禾谷类作物之首,在农业生产中占有十分重要的地位。大麦(Hordeum vulgare L.)是全球第四大禾谷类作物,具有生育期短、适应性广、耐瘠、抗逆性强等生育生理特点,且用途广泛,集经济作物、粮食作物和饲料作物于一体。虽然前人围绕着加强抗性、提高产量和改善品质开展了卓有成效的工作,但是随着全球人口增长与气候变化,对小麦和大麦的抗性、产量和品质提出了新的要求。本论文主要围绕改善小麦加工品质,加强小麦和大麦茎基腐病抗性两方面做一些研究。在改善小麦加工品质方面主要研究了四川小麦地方品种低分子量谷蛋白亚基等位基因变异及其对品质的影响；在小麦和大麦茎基腐病抗性研究方面,系统解析了茎基腐病病原菌侵染机理,并对大麦种质资源的茎基腐病抗性进行了评价和筛选；同时,对小麦茎基腐病抗性机制进行了探索。取得了以下主要研究结果：1.利用分子标记技术,对67份四川小麦地方品种的低分子量谷蛋白亚基等位基因位点进行了鉴定,结果表明低分子量谷蛋白亚基等位基因变异较大,在Glu-3位点发现13种不同类群LMW-GS基因组合的类型,其中a组合类型(包括第一、第二和第八类群的LMW-GS基因)、f组合类型(包括第三和第四类群的LMW-GS基因)和i组合类型(包括第五、第六、第七和第九类群的LMW-GS基因)分别为Glu-A3、Glu-B3和Glu-D3位点的优势类型。通过对低分子量谷蛋白亚基等位基因变异对品质相关指标影响的分析,在Glu-A3位点,发现第二类群的LMW-GS基因对小麦蛋白质含量、沉降值、湿面筋含量和稳定时间均具有负效应；在Glu-B3位点,发现第四类群的LMW-GS基因小麦面粉的面团稳定时间具有正效应：在Glu-D3位点,发现第五类群的LMW-GS基因对小麦湿面筋含量具有正效应,而第七类群的LMW-GS基因对小麦湿面筋含量具有负效应。2.利用小麦株高近等基因系,研究了小麦株高与茎基腐病抗性的相关性,发现在全部12对近等基因系中,矮秆基因型均比相对应的高秆基因型表现更好的茎基腐病抗性。同时,对12对近等基因系的赤霉素处理实验发现,赤霉素处理后导致所有基因型茎基腐病抗性下降,并且茎基腐病抗性变幅与苗长变幅呈负相关。因此,证实了矮秆基因增强茎基腐病抗性,外源赤霉素负向调节茎基腐病抗性,并推测细胞密度是造成高矮秆基因型茎基腐病抗性差异的重要因素之一。3.利用RT-qPCR技术测定了4对小麦株高近等基因系中9个防卫相关基因在不同生长发育时期被茎基腐病病原菌诱导的表达模式。结果发现PR3和PR4基因在不同生长发育时期和不同基因型中均被茎基腐病病原菌显著诱导上调表达,表明PR3和PR4基因是小麦茎基腐病病原菌侵染过程中的关键防卫反应基因。同时,分析了防卫相关基因分别在矮秆基因型和相对应的高秆基因型中的表达模式,没有发现在全部矮杆基因型中都一致被强诱导上调表达的防卫相关基因,表明矮秆基因型比高秆基因型具有更好茎基腐病抗性的原因可能不是由于矮秆基因调控防卫反应基因造成的,这对下一步寻找小麦株高近等基因系中高矮秆基因型茎基腐病抗性差异的原因提供了线索。4.利用RT-qPCR测定了不同时期茎基腐病病原菌在三个小麦品种(Kennedy、Sunco和Wolloroi)和六个大麦品种(Commander、Dash、Franklin、Gairdner、Lockyer和Mundah)茎基部的相对含量。发现茎基腐病病原菌侵染小麦及大麦茎基部有三个明显的阶段：1)品种茎基腐病病原菌相对含量显著上升的阶段；2)品种茎基腐病病原菌相对含量显著下降的阶段；3)品种茎基腐病病原菌相对含量再次显著上升的阶段。同时,通过比较大麦与小麦的相对茎基腐病病原菌含量,发现大麦相对菌含量明显高于小麦相对菌含量,表明大麦比小麦更易感茎基腐病。5.对1047份大麦种质资源进行了茎基腐病抗性鉴定,结果表明：当今大麦主栽品种抗性较差,全部高感茎基腐病,因此挖掘具有茎基腐病抗性的大麦资源,培育抗茎基腐病品种迫在眉睫；在澳大利亚冬季谷物中心随机选择的993份大麦资源材料中,没有发现茎基腐病免疫材料,但发现高抗材料33份,占总数的3%,包括147982、148012、140093、140961、151952、148090等,中抗材料47份,占总数的5%,其余92%的大麦种质资源均为感病材料。该结果明确了大麦种质资源的茎基腐病抗性,发现了一些优异的茎基腐病抗性资源材料,为改良大麦主栽品种的茎基腐病抗性提供了物质基础。更多还原

【Abstract】 Triticeae crops consist of wheat, barley, oat, rye and triticale. Wheat (Triticum aestivum L.) is one of the most important cereal crops in both the world and China, which coupled with rice and maize as top three cereal crops in the world. Its planting areas and production are on the top of the cereal crops. Wheat plays an important role in agricultural industry. Barley (Hordeum vulgare L.) is the forth largest cereal crop all over the world. It harbors lots of advantages, including fast life cycle, drought-resistance, and so on and could be used as economical, edible and forage crops. Although great achievement has been made in improvement of productivity, quality and resistance in both wheat and barley, more would be expected because of population growth and increasing demanding in life improvement. In this study, some basic researches have been made on wheat processing qualities and enhancing resistances to crown rot in wheat and barley. To improve processing qualities, high-and low-molecular gluten alleles in the Sichuan wheat landraces were investigatedand the relationships between LMW-GS gene groups and quality were examined. Meanwhile, the variations of Waxy genes in the common wheat germplasm resources were characterized. For resistance to crown rot in wheat and barley, crown rot infection mechanism was evaluated systematically and crown rot resistance materials from barley germplasm resources were identified. Crown rot resistance mechanism in wheat was also examined.1. Molecular markers were used to assess the genetic variation of low molecular weight glutenin subunit (LMW-GS) genes in 67 Sichuan wheat landraces from China. Five, three and five types of different LMW-GS allele compositions were identified, and a (including the first, second and eighth groups of LMW-GS genes),f(including the third and fourth groups of LMW-GS genes) and i (including the fifth, sixth, tseventh and ninth groups of LMW-GS genes) were the dominant types at the Glu-A3, Glu-B3 and Glu-D3 loci, respectively. The relationship between the variations in LMW-GS gene groups and quality characters were analyzed, indicating that the second LMW-GS gene group had negative effect on protein content, sedimentation value, wet gluten content and stability time at the Glu-A3, the fourth LMW-GS gene group had positive effect on stability time at the Glu-B3 and the fifth LMW-GS gene group had positive effect on wet gluten content at the Glu-D3.2. Potential effects of plant height on Fusarium crown rot (CR) disease severity were investigated using 12 pairs of near-isogenic lines (NILs) for six different reduced height (Rht) genes in common wheat. Remarkably, all the dwarf isolines gave better CR resistance compared to their respective tall counterparts, although the six Rht genes involved are located on five different chromosomes. For all of the genotypes tested, the plants treated with exogenous gibberellin increased CR severity as well as seedling lengths, confirming the Rht genes’ positive influence and exogenous gibberellin’s negative influence on the CR resistance.3. The expression of nine defense-related genes at different developmental stages in four wheat plant height NILs was analyzed using real-time quantitative polymerase chain reaction.The results indicated that PR3 and PR4 genes were the key defence genes during Fusarium infection. But no defence gene was found to be consistently upregulated in any of the dwarf genotypes when induced by F. pseudograminearum, indicating that the resistance of dwarf lines was not due to enhanced defense gene induction.4. To characterize crown rot (CR) developmental process, real-time quantitative polymerase chain reaction analyses were used to assess fungal colonization during a timecourse of infection at the stem base of three wheats (Kennedy, Sunco and Wolloroi) and six barley varieties (Commander, Dash, Franklin, Gairdner, Lockyer and Mundah). Three distinct phases of infection were identified:1) a significant increase in relative fungal biomass,2) a statistically significant decrease in fungal biomass, and 3) again, a statistically significant increase in relative biomass.5. To identify crown rot resistance barley germplasm, a total of 1047 barley germplasm accessions were evaluated. The results indicated that most of barley cultivars can be highly infected by F. pseudograminearum. Only 33 highly resistance barely accessions (3%),47 intermediate resistance accession (5%) were identified from 993 barley germplasm accessions conserved in Australia Winter Cereal Collection (AWCC). No barley accesion was found to be immune to this disease.更多还原