大豆苗期根系耐旱性关联分析及元分析

【作者】 刘鑫；

【导师】 王洋；

【作者基本信息】 黑龙江大学 ， 植物保护， 2023， 硕士

【摘要】 干旱是一种严重影响作物生长发育,导致产量减少的非生物胁迫。大豆[Glycin Max(L.)Merr.]是重要的油料作物,属于干旱敏感型作物。大豆苗期对干旱胁迫非常敏感,其中根系最先感受到土壤水分的变化,并且能够最快地发生生理生化的改变。大豆根系的耐旱性为数量性状,受到遗传与非遗传的多方面因素影响。探索大豆苗期根系耐旱性状的遗传特性,能够为分子标记辅助育种提供理论支撑,进而提高大豆产量对于保障我国食品安全具有重要作用。本研究针对152份和326份北方春大豆种质,在苗期利用称重法控制水分含量,多次干旱复水模拟干旱环境,鉴定两个群体根系耐旱性。使用30519个SNP标记对152份大豆群体和326份大豆群体进行基因组扫描,使用210对SSR标记对152份大豆群体进行基因组扫描,分析遗传多样性,群体结构及连锁不平衡的特点,结合表型性状进行关联分析。收集近15年以来不同来源的干旱下大豆根系性状的遗传图谱,以83个根系耐旱性状QTL为基础,利用Biomercator 4.2软件,在Soybase 2图谱上映射得到一致性图谱,并进行元分析。对关联分析得到的SNP位点、SSR位点和元分析通用QTL区间比对得到相近区间,对相近区间进行基因注释。结果如下:对152份和326份北方春大豆苗期根系耐旱性状进行描述性统计,152份大豆种质变异系数在10.79%-39.92%之间,相对耐旱根尖数变异系数最大,为39.92%,326份大豆种质变异系数在5.77%-15.21%之间,相对耐旱主根长变异系数最大,为15.21%。表明各性状均存在广泛的遗传变异。利用主成分分析以及隶属函数方法,152份大豆群体中筛选出丰收七号这一极端耐旱品种,326份大豆群体中筛选出永丰豆、铁荚青、通农5号、39238和绿楂豆5个极端耐旱品种。其中丰收七号D值最高,为0.95。通过使用SNP和SSR对两个群体进行关联分析,使用混合线性模型(MLM),同时以亲缘关系矩阵和群体结构结果Q矩阵作为协变量矫正模型,在-Log10(P)≥3.5或-Log10(P)≥4的显著水平下,共关联到157个与大豆苗期根系耐旱性状相关联的SNP位点。其中152份大豆群体关联到76个SNP标记,分布在大豆的17条染色体上,5号和16号染色体上关联到的SNP标记最多,各有20个。152份大豆群体关联到51对SSR标记位点,分布在大豆的19条染色体上,其中13号染色体关联到的SSR标记最多,有7对。326份大豆群体关联到81个SNP标记,分布在大豆的18条染色体上,其中8号染色体上关联到的SNP标记最多,有12个。元分析以83个已发表的大豆根系耐旱QTL为基础,通过运算后得到12个通用QTL位点。将两个群体关联到的位点与通用QTL区间的物理位置比对,使得157个SNP显著位点被优化到20个,其中18号染色体上的ss715630660标记和ss715632811标记同时在多种分析方法中被检测到。查找21个位点其位置周边50kb大小区域内的大豆基因,并对其拟南芥同源基因功能进行分析,最终得到57个大豆基因,并且周边有已发表基因8个,发表基因中存在MYB88、b ZIP111与大豆耐旱性密切相关,证明该联合分析的方式能够提供一种新颖的位点验证模式。通过查找大豆基因的拟南芥同源基因功能从而对大豆基因功能进行预测,得到Glyma.03g250600、Glyma.05g157000、Glyma.05g157400和Glyma.06g177000四个可能与大豆苗期根系耐旱密切相关的基因。更多还原

【Abstract】 Drought is an abiotic stress that seriously affects crop growth and development and leads to reduced yield.Soybean [Glycin Max(L.)Merr.] is an important oil crop and is a drought-sensitive crop.Soybean seedlings are very sensitive to drought stress,in which the roots are the first to feel the change of soil moisture,and can quickly change the physiological and biochemical changes.The drought tolerance of soybean roots is a quantitative trait,which is affected by many factors of heredity and non heredity.Exploring the genetic characteristics of soybean root drought tolerance at seedling stage can provide theoretical support for molecular marker-assisted breeding,and thus improving soybean yield plays an important role in ensuring food safety in China.In this study,152 and 326 northern spring soybean germplasms were used to control water content by weighing method at seedling stage,and multiple drought and rewatering were used to simulate drought environment to identify root drought tolerance of the two groups.The genomes of 152 soybean populations and 326 soybean populations were scanned using 30519 SNP markers,and the genomes of 152 soybean populations were scanned using 210 pairs of SSR markers to analyze genetic diversity,population structure and linkage disequilibrium.The genetic maps of soybean root traits under drought from different sources in the past 15 years were collected.Based on 83 QTLs for root drought tolerance traits,a consensus map was mapped on the Soybase 2map using Biomercator 4.2 software,and meta-analysis was performed.The SNP loci,SSR loci and meta-analysis general QTL intervals obtained by association analysis were compared to obtain similar intervals,and the similar intervals were annotated.The results are as follows :The descriptive statistics of root drought tolerance traits of 152 and 326 northern spring soybean seedlings were carried out.The coefficient of variation of 152 soybean germplasm was between 10.79 % and 39.92 %,and the coefficient of variation of relative drought-tolerant root tip number was the largest,which was 39.92 %.The coefficient of variation of 326 soybean germplasm was between 5.77 % and 15.21 %,and the coefficient of variation of relative drought-tolerant main root length was the largest,which was 15.21 %.It shows that there are extensive genetic variations in all traits.Using principal component analysis and membership function method,152 soybean populations were screened for the extremely drought-tolerant variety Fengshou7,and 326 soybean populations were screened for the extremely drought-tolerant varieties Yongfengdou,Tiejiaqing,Tongnong 5,39238 and Lvzhadou.The D value of Fengshou 7 was the highest,which was 0.95.The association analysis of the two populations was carried out by using SNP and SSR,and the mixed linear model(MLM)was used.At the same time,the genetic relationship matrix and the population structure result Q matrix were used as the covariate correction model.At the significant level of-Log10(P)≥ 3.5 or-Log10(P)≥ 4,a total of 157 SNP loci associated with drought tolerance of soybean roots at seedling stage were associated.Among them,152 soybean populations were associated with 76 SNP markers,distributed on 17 chromosomes of soybean,and the most SNP markers were on chromosomes 5 and 16,with 20 SNP markers each.A total of 51 pairs of SSR markers were associated with 152 soybean populations,which were distributed on 19 chromosomes of soybean.Among them,chromosome 13 had the most SSR markers,with 7 pairs.A total of 81 SNP markers were associated with 326 soybean populations,distributed on 18 chromosomes of soybean,of which 12 SNP markers were associated on chromosome 8.Based on 83 published soybean root drought tolerance QTLs,12 common QTLs were obtained by meta-analysis.By aligning the loci associated with the two populations with the physical location of the common QTL interval,157 SNP significant loci were optimized to 21,of which the ss715630660 marker and ss715632811 marker on chromosome 18 were simultaneously detected in multiple analysis methods.The soybean genes in the 50 kb region around the location of 20 sites were searched,and the functions of their Arabidopsis homologous genes were analyzed.Finally,57 soybean genes were obtained,and there were 8 published genes around them.The presence of MYB88 and b ZIP111 in the published genes was closely related to the drought tolerance of soybean,which proved that the combined analysis method could provide a novel site verification mode.The function of soybean gene was predicted by searching the homologous gene function of soybean gene in Arabidopsis thaliana.Four genes,Glyma.03g250600,Glyma.05g157000,Glyma.05g157400 and Glyma.06g177000,which may be closely related to drought tolerance of soybean seedling roots were obtained.更多还原