棉花-花生轮作下的根系土壤细菌群落结构及功能分析

为了提升棉花和花生产量,开展棉花-花生轮作模式研究,分析轮作模式下土壤根系微生物的群落结构与功能。以棉花连作、花生连作、棉花花生轮作、花生棉花轮作和休耕为研究对象,探明轮作后作物根际土壤微生物群落结构变化,利用16S rRNA基因高通量测序技术分析根系细菌群落结构与功能。结果发现:轮作提高了根系细菌群落的多样性;土壤样本中共获得5009952个有效序列,休耕模式下OTU(operational taxonomic units)含量最多。在轮作种植模式中变形菌门、酸杆菌门和放线菌门为优势菌门;其次轮作模式增加了厚壁菌门、拟杆菌门和芽单胞菌门的丰富度。根据功能不同,将菌群共划分为8类,轮作出现较多微生物基因遗传相关的功能类群,整体以代谢相关的类群居多,与人类和植物病原菌的功能蛋白组富集明显。由此得出,棉花,花生轮作能够提高微生物丰富度,增加多样性,改变土壤微生物群落结构,促进作物根系对营养物质的吸收,提高作物产量。

不同多年生稻品种内生细菌群落多样性比较分析

【目的】为了解多年生稻内生细菌微生态的结构和潜在功能,探究多年生稻内生细菌与寄主优良性状的关系。【方法】通过16S rRNA扩增子测序技术比较分析了不同多年生稻品种(PR23、PR25和PR107)内生细菌多样性、物种组成和代谢功能。【结果】不同基因型的多年生稻具有不同的内生细菌群落,三者β多样性存在显著差异。多年生稻地下和地上部组织分化形成了不同的内生细菌群落,其地下部内生细菌主要由变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)等组成,而地上部内生细菌主要由变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)等组成。不同多年生稻内生细菌特有扩增子序列变体(amplicon sequence variants,ASVs)数量较多,且具有不同的优势内生细菌属和生物标记物种类。多年生稻内生细菌的代谢功能主要为生物合成、生物降解与利用、解毒、代谢产物前体和能量的产生、甘氨酸途径、大分子修饰和代谢簇。品种间内生细菌的差异代谢功能主要涉及酯类、醇类、糖类等物质的生物合成和降解。【结论】寄主基因型和组织分化影响了多年生稻内生细菌的群落结构、物种组成和代谢功能。

479份芥菜型油菜种质资源萌发期耐盐性综合评价

为了解不同芥菜型油菜种质资源的耐盐程度,本研究利用0、150、200和250 mmol/L浓度的NaCl溶液对479份来自不同国家的芥菜型油菜种质资源进行盐胁迫处理,并测定发芽率、根长、芽长和鲜重;采用主成分分析、隶属函数、多元线性回归分析和聚类分析对参试材料的耐盐性进行综合评价。结果发现在200 mmol/L的NaCl溶液处理下,可以有效地将479份材料划分为4类,第I类为耐盐品种12份,第Ⅱ类为75份中等耐盐品种,第Ⅲ类为313份不耐盐品种,第Ⅳ类为79份盐极敏感品种,并建立了芥菜型油菜耐盐性鉴定的多元线性回归方程,y=0.537x1+0.310x2+0.089x3+0.064x4。筛选得到的耐盐性材料为培育油菜耐盐新品种奠定基础。

普通野生稻内生细菌的分离鉴定及其对多年生稻的促生效果

普通野生稻(Oryza rufipogon)是具有丰富的生境、遗传和微生物多样性的野生稻资源,挖掘其内生细菌资源可为普通野生稻微生态研究和生物菌肥开发提供菌种资源.研究首次从云南元江普通野生稻的根、茎和叶3种组织分离获得了111株内生细菌,其中82株具有溶磷能力,23株具有固氮作用,50株可产铁载体,18株可产吲哚乙酸(indole-3-acetic acid,IAA).分离自茎部的枯草芽孢杆菌(Bacillus subtilis)ORS2-5菌株、路德维希肠杆菌(Enterobacter ludwigii)ORS1-2菌株和分离自叶部的水稻科萨克氏菌(Kosakonia oryzae)ORL3-1具有较高的IAA分泌量,分别为11.69、22.81 mg/L和24.62 mg/L.3个菌株对多年生稻具有显著促生效果,可以不同程度地提高多年生稻幼苗的根长、鲜重、叶绿素和氮素质量比.研究结果将为多年生稻生态菌肥开发提供菌种资源,助力多年生稻绿色轻简化的生产模式.

Seed Length Controlled by Same Locus in Four Different AA Genome Species of Genus Oryza

To broaden the genetic basis and overcome the yield plateau in Asian cultivated rice, the exploitation and utilization of favorable alleles from rice species with the AA genome has become important and urgent in modern breeding programs. Four different interspecific populations were used to detect quantitative trait locus （QTL） for seed length, including a BC4F2 population derived from Oryza glumaepatula crossed with Dianjingyou 1 （a japonica cultivar）, a BC4F2 population derived from O. nivara crossed with Dianjingyou 1, a BCzF1 population derived from a cross between O. Iongistaminata and RD23 （an indica cultivar）, and a BCsF1 population derived from a cross between O. glaberrima and Dianjingyou 1. The QTLs for seed length in four different populations were termed as SL-3a, SL-3b, SL-3c and SL-3d, respectively. They had good collinearity and accounted for 49% to 60% of the phenotypic variations. Sequencing data indicated that four QTLs were different alleles of GS3 which were responsible for the seed length variation between O. sativa and its four AA genome relatives. These results will be valuable for confirming the evolution of GS3 and also be helpful for rice breeding.

Molecular Mapping of Sterility QTLs qSS-3, qSS-6a and qSS-7 as Single Mendelian Factors via NIL strategy

Hybrid sterility between Oryza glaberrima and O. sativa seriously hampers the introgression of favorable genes from each other. In order to further understand this issue, identification and isolation of hybrid sterility QTLs as single Mendelian factors are an effective strategy. A genetic map was constructed using a BC1 F1 population derived from a cross between an O. safiva japonica cultivar and an O. glaberrima accession. Four main-effect QTLs for pollen sterility were detected in the BC1F1. Five BC8F1 advanced backcross populations were developed via successive backcrosses based on phenotype and molecular selections. The BC8F1 populations showed bimodal distribution for pollen fertility and could be classified into semi-sterile and fertile types, fitting single Mendilian factor inheritance ratios. Three QTLs detected in the BC1F1 corresponding to qSS-3, qSS-6a and qSS-7 were mapped on chromosomes 6, 3 and 7, respectively, as single Mendilian factors.

一种两收模式下多年生稻产量潜力初探

以多年生稻品系PR25和再生稻品种渝粳优5029(RR1)、甬优1540(RR2)、佳辐占(RR3)、宜优673(RR4)、内优7075(RR5)为材料,采用单因素试验探讨多年生稻与再生稻产量、产量构成、生育期、SPAD、根系活力等性状的异同。结果表明:PR25产量与再生稻相比,头季持平或者略低,第二季PR25产量为471.10 kg/667m^2,显著高于所有再生稻品种,较RR1、RR2、RR3、RR4和RR5分别增产48.22%、34.79%、60.95%、31.71%、45.58%;周年产量PR25为1031.63 kg/667m^2,亦显著大于再生稻品种,较RR1、RR2、RR3、RR4和RR5分别增产5.82%、10.41%、47.00%、13.19%和42.66%。多年生稻PR25再生季的周年产量较再生稻高的主要原因是:多年生稻再生季的单位面积颖花数、有效穗数和结实率均高于再生稻的再生季;PR25头季齐穗后剑叶SPAD衰减幅度较小,剑叶具有较强的光合能力,头季成熟期根系维持在较高活力水平且再生能力较强;多年生稻再生季营养生长期至营养生长与生殖生长并进期明显长于再生稻,进而全生育期较再生稻呈延长趋势,利于干物质积累。