水稻株形对纹枯病抗性的影响

利用240份源于珍汕97B／明恢63的重组自交系水稻(Oryza sativa L.)群体,连续2年调查纹枯病病级与水稻生育期、株高和叶片长宽等18个株形性状的关系。对株形性状与纹枯病病级进行了偏相关分析。实验结果,只有植株松紧度与病级表型偏相关两年中都达到了显著或极显著水平,倒2叶基角、穗层整齐度等8个性状与病级之间的偏相关只有一年达显著或极显著水平。结合构建的分子标记遗传连锁图谱,对各性状进行QTL定位。在抗纹枯病QTL相近区间仅检测到控制分蘖角、植株松紧度和倒2叶基角的QTLs,未发现其余株形性状QTLs与抗纹枯病QTLs分布在同一染色体上。结果表明,水稻对纹枯病的抗性主要是由本身抗性基因控制,株形对纹枯病抗性表达的影响主要是间接影响,即通过改变田间小气候而影响发病程度。抗纹枯病育种在累加主效抗纹枯病QTLs的同时,也要注重选择不利于纹枯病发展的株形性状。     

水稻株形对纹枯病抗性的影响

利用240份源于珍汕97B/明恢63的重组自交系水稻(Oryza sativa L.)群体,连续2年调查纹枯病病级与水稻生育期、株高和叶片长宽等18个株形性状的关系.对株形性状与纹枯病病级进行了偏相关分析.实验结果,只有植株松紧度与病级表型偏相关两年中都达到了显著或极显著水平,倒2叶基角、穗层整齐度等8个性状与病级之间的偏相关只有一年达显著或极显著水平.结合构建的分子标记遗传连锁图谱,对各性状进行QTL定位.在抗纹枯病QTL相近区间仅检测到控制分蘖角、植株松紧度和倒2叶基角的QTLS,未发现其余株形性状QTLs与抗纹枯病QTLs分布在同一染色体上.结果表明,水稻对纹枯病的抗性主要是由本身抗性基因控制,株形对纹枯病抗性表达的影响主要是间接影响,即通过改变田间小气候而影响发病程度.抗纹枯病育种在累加主效抗纹枯病QTLs的同时,也要注重选择不利于纹枯病发展的株形性状.     

水稻R基因同源序列与遗传学上已知抗病基因的共定位(英文)

植物抗病（R）基因结构上的高度保守性,为利用基于PCR的方法快速分离R基因同源序列提供了基础。采用这种方法,我们曾从水稻中分离到8个R基因候选同源序列（Rgenecandidates,RGCs）。为了研究RGCs与遗传学上已知的R基因的关系,对它们进行了限制性片段长度多态性（RFLP）分析和染色体定位。DNA杂交结果显示RGCs都属于多基因家族（Fig．1）。6个RGCs（Osh359－1、Osh359－2、Osh359－3、Osh359－5、Os8558－3、Os8558－14）在两个籼稻品种H359和Acc8558中检测出多态性,并定位在水稻染色体上（Fig．2）。它们分别检测出了1、1、4、1、2和1个座位,共10个座位,其中9个定位在第11号染色体的3个区域上,即RFLP标记G181和C82之间（由Osh359－2、Osh359－3、Osh359－5和Os8558－3检测的6个座位）,G1465与C50之间（Osh359－3检测出的一个座位）,和C496附近（由Osh359－1和Os8558－14检测出的两个紧密连锁的座位）另有一个由Os8558－3检测出的座位定位到第8号染色体上,位于L457和G1082B之间。这些染色体区域包含近一半的遗传学上已知的抗病基因,如Xa-3、Xa－10、Pi－a和xa－13。这一结果表明RGCs与已知的抗病基因位于相同的染色体区域。此外,RGCs定位的结果表明,它们在水稻基因组中呈簇状分布,表现出     

Modern elite rice varieties of the 'Green Revolution' have retained a large introgression from wild rice around the Pi33 rice blast resistance locus

During the breeding process of cultivated crops, resistance genes to pests and diseases are commonly introgressed from wild species. The size of these introgressions is predicted by theoretical models but has rarely been measured in cultivated varieties. By combining resistance tests with isogenic strains, genotyping and sequencing of different rice accessions, it was shown that, in the elite rice variety IR64, the resistance conferring allele of the rice blast resistance gene Pi33 was introgressed from the wild rice Oryza rufipogon (accession IRGC101508). Further characterization of this introgression revealed a large introgression at this locus in IR64 and the related variety IR36. The introgressed fragment represents approximately half of the short arm of rice chromosome 8. This is the first report of a large introgression in a cultivated variety of rice. Such a large introgression is likely to have been maintained during backcrossing only if a selection pressure was exerted on this genomic region. The possible traits that were selected are discussed.     

对水稻4号染色体一个编码S位点相关的受体样蛋白激酶基因簇的分析

通过对水稻(Oryza sativa L.) 4号染色体一段323 kb 的序列测定和分析,在其中108 kb的区域内发现了一个由14个编码S位点相关的受体样蛋白激酶(SRK)基因组成的基因簇.RT-PCR实验证明了这14个基因中有9个基因表达,并且这9个基因有不同的表达模式: 其中2个基因主要在生殖器官中表达, 而另外7个基因在水稻的营养和生殖器官中均有表达.对这些基因的预测的氨基酸序列进行分析表明他们的细胞外受体部分均和甘蓝的SLG蛋白高度同源,而细胞内的激酶区都包含有丝氨酸/苏氨酸激酶中特异的氨基酸.     

Systematic analysis of rice (Oryza sativa) metabolic responses to herbivory

Plants defend against attack from herbivores by direct and indirect defence mechanisms mediated by the accumulation of phytoalexins and release of volatile signals, respectively. While the defensive arsenals of some plants, such as tobacco and Arabidopsis are well known, most of rice's (Oryza sativa) defence metabolites and their effectiveness against herbivores remain uncharacterized. Here, we used a non‐biassed metabolomics approach to identify many novel herbivory‐regulated metabolic signatures in rice. Most were up‐regulated by herbivore attack while only a few were suppressed. Two of the most prominent up‐regulated signatures were characterized as phenolamides (PAs), p‐coumaroylputrescine and feruloylputrescine. PAs accumulated in response to attack by both chewing insects, i.e. feeding of the lawn armyworm (Spodoptera mauritia) and the rice skipper (Parnara guttata) larvae, and the attack of the sucking insect, the brown planthopper (Nilaparvata lugens, BPH). In bioassays, BPH insects feeding on 15% sugar solution containing p‐coumaroylputrescine or feruloylputrescine, at concentrations similar to those elicited by heavy BPH attack in rice, had a higher mortality compared to those feeding on sugar diet alone. Our results highlight PAs as a rapidly expanding new group of plant defence metabolites that are elicited by herbivore attack, and deter herbivores in rice and other plants.     

Host plant defense signaling in response to a coevolved herbivore combats introduced herbivore attack

Defense‐free space resulting from coevolutionarily naïve host plants recently has been implicated as a factor facilitating invasion success of some insect species. Host plants, however, may not be entirely defenseless against novel herbivore threats. Volatile chemical‐mediated defense signaling, which allows plants to mount specific, rapid, and intense responses, may play a role in systems experiencing novel threats. Here we investigate defense responses of host plants to a native and exotic herbivore and show that (1) host plants defend more effectively against the coevolved herbivore, (2) plants can be induced to defend against a newly‐associated herbivore when in proximity to plants actively defending against the coevolved species, and (3) these defenses affect larval performance. These findings highlight the importance of coevolved herbivore‐specific defenses and suggest that naïveté or defense limitations can be overcome via defense signaling. Determining how these findings apply across various host–herbivore systems is critical to understand mechanisms of successful herbivore invasion.