Better understanding of genotype-by-environment interaction(GEI)is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments.To elucidate the genetic basis of the plant and ear height,2 F2:3 populations were derived from the crosses of Qi 319 × Huangzaosi(Q/H)and Ye 478 × Huangzaosi(Y/H)with 230 and 235 families,respectively,and their parents were evaluated under 3 diverse environments in Henan,Beijing,and Xinjiang,China during the year of 2007 and 2008,and all the lines were also evaluated under water stress environment.The mapping results showed that a total of 21 and 12 QTLs were identified for plant height in the Q/H and Y/H population,respectively,and 24 and 13 QTLs for ear height,respectively.About 56 and 73% of the QTLs for 2 traits did not present significant QTL-by-environment interaction(QEI)in the normal joint analyses for Q/H and Y/H population,respectively,and about 73% of the QTLs detected did not show significant QEI according to joint analyses for stress condition in Q/H.Most of the detected major QTLs exhibited high stability across different environments.Besides,several major QTLs were detected with large and consistent effect under normal condition(Chr.6 and 7 in Q/H;Chr.1,3 and 9 in Y/H),or across 2 water regimes(Chr.1,8 and 10 for in Q/H).There were several constitutive QTLs(3 for Q/H and 1 for Y/H)with no or minor QTL-by-environment for the 2 populations.Finally,we found several genomic regions(Chr.1,10,etc.)to be co-located across the populations,which could provide useful reference for genetic improvement of these traits in maize breeding programs.Comparative genomic analysis revealed that 3 genes/genetic segments associated with plant height in rice were orthologous to these 3 identified genomic regions carrying the major QTLs for plant and ear height on Chr.1,6,and 8,respectively.
植物病毒病是一类严重危害农作物生产的重要病害。已报道的植物抗病毒基因主要在抑制病毒增殖和阻止病毒扩散中起作用。病毒的复制涉及自身的编码蛋白及其与寄主蛋白间的互作,参与病毒复制的寄主蛋白很多,如真核翻译起始因子eIF4E和eIF4G,植物的内膜系统等,相关蛋白的功能丧失或构型改变可阻滞病毒的复制;此外,植物细胞内的硫氧还蛋白可调节细胞的氧化还原状态,进而阻断病毒的增殖。病毒在植物体内的扩散包括胞间移动和长距离迁移,植物抗病蛋白(R蛋白)通过识别病毒的无毒因子(Avr)促发防御反应,诱导过敏性坏死,限制病毒在细胞间的扩散,编码这类抗病蛋白的基因主要为TIR-NBS-LRR和CC-NBS-LRR。病毒的长距离迁移涉及的因素很多,目前仅发现韧皮部的RTM蛋白可能以多聚蛋白的形式抵制病毒的长距离移动。另外,RNA沉默也是植物抵制病毒侵染的免疫反应机制。本文旨在综述植物的各种抗病毒机制和相关的抗病基因,并探讨分子标记辅助选择(marker-assisted selection,MAS)、定向诱导基因组局部突变(targeting induced local lesions in genomes,TILLING)和转基因等生物技术在抗病改良中的应用前景。
