基于大刍草渗入系的玉米抗旱优异等位基因挖掘

干旱是影响玉米生产的主要非生物胁迫之一。为了挖掘玉米优异抗旱基因,本研究基于墨西哥大刍草和玉米自交系PH4CV构建的BC2F6群体,通过苗期抗旱性初步鉴定,筛选出抗旱性强的渗入系TP180。干旱胁迫后发现渗入系TP180较轮回亲本PH4CV萎蔫程度更小,并且复水后存活率显著高于PH4CV。全基因组基因型鉴定发现,渗入系TP180含有0.6%的墨西哥大刍草导入。通过开展TP180和PH4CV不同水分条件下的转录组测序,在渗入系TP180和PH4CV之间共鉴定了2307个差异表达基因,不同胁迫重叠差异表达基因共122个,这些基因涉及生长素途径,茉莉酸途径等,包含多个转录因子。整合差异表达基因和含大刍草导入区段分析,鉴定出2个抗旱候选基因Zm00001d033050和Zm00001d002025,并进一步开展了RT-PCR分析。本研究为挖掘大刍草中抗旱基因资源提供了重要材料和信息基础。

Genetic dissection of crown root traits and their relationships with aboveground agronomic traits in maize

The crown root system is the most important root component in maize at both the vegetative and reproductive stages. However, the genetic basis of maize crown root traits(CRT) is still unclear, and the relationship between CRT and aboveground agronomic traits in maize is poorly understood. In this study, an association panel including 531 elite maize inbred lines was planted to phenotype the CRT and aboveground agronomic traits in different field environments. We found that root traits were significantly and positively correlated with most aboveground agronomic traits, including flowering time, plant architecture and grain yield. Using a genome-wide association study(GWAS)coupled with resequencing, a total of 115 associated loci and 22 high-confidence candidate genes were identified for CRT. Approximately one-third of the genetic variation in crown root was co-located with 46 QTLs derived from flowering and plant architecture. Furthermore, 103 (89.6%) of 115 crown root loci were located within known domestication-and/or improvement-selective sweeps, suggesting that crown roots might experience indirect selection in maize during domestication and improvement. Furthermore, the expression of Zm00001d036901, a high-confidence candidate gene, may contribute to the phenotypic variation in maize crown roots, and Zm00001d036901 was selected during the domestication and improvement of maize. This study promotes our understanding of the genetic basis of root architecture and provides resources for genomics-enabled improvements in maize root architecture.

一种面向液压储能器的122 GHz FMCW测距雷达

针对液压储能器活塞位移测量过程中存在的高温、高压、油污等影响问题,提出了基于122 GHz FMCW测距雷达的活塞位移测量方案。在分析雷达系统结构和工作原理的基础上,分别对调制信号单元、T/R收发单元、调理单元和ARM实时处理单元进行了详细设计,一方面采用集成设计思路缩小了系统体积,满足了液压储能器内安装测试需求,另一方面通过设计聚焦透镜,提高了122 GHz毫米波在液压储能器内部的穿透能力。实验结果表明,在2 m液压储能器活塞测试中,122 GHz FMCW测距雷达能够耐压30 MPa,测距误差不超过2 cm。

玉米CIPK基因家族的鉴定及ZmCIPK3的抗旱性功能研究

钙调磷酸酶B类互作蛋白激酶(CIPK,CBL interacting protein kinases)是植物钙离子信号通路中响应非生物逆境胁迫的重要蛋白激酶之一。本研究以拟南芥和水稻中CIPK家族基因序列信息为基础,利用玉米参考基因组B73和生物信息学分析方法,全基因组范围内鉴定玉米CIPK基因家族成员,分析CIPK家族基因的进化关系、基因结构、基因表达模式和对干旱胁迫的响应。本研究共鉴定出44个玉米CIPK家族基因,并将其分为5个亚家族,每个亚家族有不同的外显子-内含子和UTR的结构特征;基于基因差异表达分析,筛选出5个与抗旱性相关的候选基因ZmCIPK3、ZmCIPK7、ZmCIPK44、ZmCIPK25和ZmCIPK28;进一步的遗传数据表明,干旱胁迫下ZmCIPK3拟南芥转基因株系的存活率明显高于野生型,提高了拟南芥的抗旱性;同时,干旱胁迫下ZmCIPK3拟南芥转基因株系中抗旱性相关生化指标过氧化物酶、超氧化物歧化酶活性显著高于野生型,而丙二醛和脯氨酸的含量显著低于野生型。本研究在玉米全基因组水平上鉴定了CIPK基因家族成员,分析了其在不同抗旱性材料、不同水分处理下的基因表达模式,明确了ZmCIPK3是一个抗旱性候选基因。

玉米株高主效位点qPEH6.02育种应用价值评估

开展玉米重要性状主效位点的育种应用价值评估,对促进分子设计育种有效开展,提高种质资源遗传改良效率具有重要意义。针对前期工作中利用导入系1133B(热带玉米自交系Tzi8为供体亲本,温带骨干自交系B73为轮回亲本)定位的玉米株高主效位点qPEH6.02,本研究借助分子标记追踪,创制了主效位点的近等基因导入系1133B^(B73)和1133B^(Tzi8)。以此为试验材料,在52500株/hm^(2)、67500株/hm^(2)和82500株/hm^(2)3种不同密度下,开展了主效位点qPEH6.02近等基因导入系(1133B^(B73)和1133B^(Tzi8)),及其弱优势杂交组合(同类群自交系杂交F_(1))和强优势杂交组合(强优势类群自交系杂交F_(1))的株高和产量鉴定分析。结果发现,不同种植密度下1133B^(Tzi8)较其近等基因导入系1133B^(B73)的株高增加15.17~20.40 cm,但在其弱优势和强优势杂交组合中株高仅分别增加3.87~5.03 cm和3.23~5.97 cm。同时发现,在不同种植密度下1133B^(Tzi8)较其近等基因导入系1133B^(B73)的小区产量增加10%以上,最高可增产15.00%;在其杂交组合中小区产量提高3%以上,最高可增产8.85%,表明主效位点qPEH6.02来自热带玉米自交系Tzi8的单倍型在提高产量方面具有潜在育种应用价值。