A novel rice lesion mimic mutant (LMM) was isolated from an ethane methyl sulfonate (EMS)-induced 02428 mutant bank. The mutant, tentatively designated as lmm6, develops necrotic lesions in the whole growth period alo...A novel rice lesion mimic mutant (LMM) was isolated from an ethane methyl sulfonate (EMS)-induced 02428 mutant bank. The mutant, tentatively designated as lmm6, develops necrotic lesions in the whole growth period along with changes in several important agronomic traits. We found that the initiation of the lesions was induced by light and cel death occurred in lmm6 accompanied with accumulation of reactive oxygen species (ROS). The lower chlorophyl content, soluble protein content and superoxide dismutase (SOD) activity, the higher malondialdehyde (MDA) content were detected in lmm6 than in the wild type (WT). Moreover, the observation by transmission electronic microscope (TEM) demonstrated that some organel es were damaged and the stroma lamel a of chloroplast was irregular and loose in mesophyl cel of lmm6. In addition, lmm6 was more resistant than WT to rice blast fungus Magnaporthe grisea infection, which was consistent with increased expression of four genes involved in the defense-related reaction. Genetic analysis showed that mutant trait of lmm6 is inherited as a monogenic recessive nuclear gene located on the long arm of chromosome 6. Using simple sequence repeat (SSR) markers, the target gene was ifnal y delimited to an interval of 80.8 kb between markers MM2359 and MM2370, containing 7 annotated genes. Taken together, our results provide the information to identify a new gene involved in rice lesion mimic, which wil be helpful in clarifying the mechanism of cel death and disease resistance in rice.展开更多
A lesion mimic stripe mutant, designated as Ims1 （lesion mimic stripe 1）, was obtained from the M2 progeny of a ^60Co y-radiation treated japonica rice variety Jiahua 1. The Ims1 mutant displayed propagation type le...A lesion mimic stripe mutant, designated as Ims1 （lesion mimic stripe 1）, was obtained from the M2 progeny of a ^60Co y-radiation treated japonica rice variety Jiahua 1. The Ims1 mutant displayed propagation type lesions across the whole growth and developmental stages. Physiology and histochemistry analysis showed that the mutant exhibited a phenotype of white stripe when grown under high temperature （30 ℃）, and the lesion mimic caused by programmed cell death under low temperature （20 ℃）. The genetic analysis indicated that this lesion-mimic phenotype is controlled by a single locus recessive nuclear gene. Furthermore, by using simple sequence repeat markers and an F2 segregating population derived from two crosses of Ims1 ×93-11 and Ims1 ×Pei＇ai 64S, the Imsl gene was mapped between markers Indel1 and MM0112-4 with a physical distance of 400 kb on chromosome 6 in rice.展开更多
Phenotypical, cytological and molecular responses of rice to the fungus Magnaporthe grisea were studied using rice cultivars and lesion mimic plants. The cultivar Katy was susceptible to several virulent M. grisea iso...Phenotypical, cytological and molecular responses of rice to the fungus Magnaporthe grisea were studied using rice cultivars and lesion mimic plants. The cultivar Katy was susceptible to several virulent M. grisea isolates, and a Sekiguchi like-lesion mimic mutant of Katy （LmmKaty） showed enhanced resistance to these isolates. Lesion mimic phenotype of LmmKaty was rapidly induced by virulent M. grisea isolates or by avirulent ones only at high levels of inoculum. Autofluorescence （a sign of an active defense response） was visible under ultraviolet light 24 h after localized inoculation in the incompatible interaction, whereas, not evident in the compatible interaction. Autofluorescence was also observed in LmmKaty 20 h after pathogen inoculation, indicating that rapid cell death is a mechanism of LmmKaty to restrict pathogen invasion. Rapid accumulations of defense related （DR） gene transcripts, phenylalanine ammonia lyase and β-glucanase, were observed beginning at 6 h and were obvious at 16 h and 24 h after inoculation in an incompatible interaction. Rapid transcript accumulations of PR-1 and chitinase had occurred by 24 h after inoculation in an incompatible interaction. Accumulations of these transcripts were delayed in the compatible interaction. These results indicate that host active defense responses occur 24 h after pathogen inoculation and that LmmKaty exhibits enhanced resistance to M. grisea. It is suggested that the autofluorescence and expression of the DR genes after heavy inoculation are important cytological and molecular markers respectively for early determination of the host response to M. grisea in the rice blast system.展开更多
通过筛选籼稻恢复系明恢86的组培变异后代,获得1个类病斑及早衰突变体lms1(lesion mimic and senescence 1)。lms1植株生长至拔节期开始在叶片上出现黄褐色小斑点,随后斑点逐渐扩展至大部分叶片和茎组织;生长至抽穗期后呈现早衰,穗、茎...通过筛选籼稻恢复系明恢86的组培变异后代,获得1个类病斑及早衰突变体lms1(lesion mimic and senescence 1)。lms1植株生长至拔节期开始在叶片上出现黄褐色小斑点,随后斑点逐渐扩展至大部分叶片和茎组织;生长至抽穗期后呈现早衰,穗、茎、叶明显干枯,并快速衰亡。RT-PCR分析表明,在呈现类病斑性状叶片组织的lsm1中,病程相关基因PBZ1、PAL1表达明显高于其在野生型叶片组织中的水平。遗传分析表明,lms1的突变性状受单隐性核基因控制。利用9311与lms1配置的F2及F3群体进行基因定位,将lms1基因定位在水稻第11染色体长臂末端。展开更多
基金supported by the Major Special Foundation of Transgenic Plants in China (2013ZX001-003 and 2014ZX08009-15B)
文摘A novel rice lesion mimic mutant (LMM) was isolated from an ethane methyl sulfonate (EMS)-induced 02428 mutant bank. The mutant, tentatively designated as lmm6, develops necrotic lesions in the whole growth period along with changes in several important agronomic traits. We found that the initiation of the lesions was induced by light and cel death occurred in lmm6 accompanied with accumulation of reactive oxygen species (ROS). The lower chlorophyl content, soluble protein content and superoxide dismutase (SOD) activity, the higher malondialdehyde (MDA) content were detected in lmm6 than in the wild type (WT). Moreover, the observation by transmission electronic microscope (TEM) demonstrated that some organel es were damaged and the stroma lamel a of chloroplast was irregular and loose in mesophyl cel of lmm6. In addition, lmm6 was more resistant than WT to rice blast fungus Magnaporthe grisea infection, which was consistent with increased expression of four genes involved in the defense-related reaction. Genetic analysis showed that mutant trait of lmm6 is inherited as a monogenic recessive nuclear gene located on the long arm of chromosome 6. Using simple sequence repeat (SSR) markers, the target gene was ifnal y delimited to an interval of 80.8 kb between markers MM2359 and MM2370, containing 7 annotated genes. Taken together, our results provide the information to identify a new gene involved in rice lesion mimic, which wil be helpful in clarifying the mechanism of cel death and disease resistance in rice.
基金supported by the National Basic Research Program of China (Grant No. 2009CB119000)the National Science Foundation of China (Grant Nos.31000094,31100188 and 30970246)
文摘A lesion mimic stripe mutant, designated as Ims1 （lesion mimic stripe 1）, was obtained from the M2 progeny of a ^60Co y-radiation treated japonica rice variety Jiahua 1. The Ims1 mutant displayed propagation type lesions across the whole growth and developmental stages. Physiology and histochemistry analysis showed that the mutant exhibited a phenotype of white stripe when grown under high temperature （30 ℃）, and the lesion mimic caused by programmed cell death under low temperature （20 ℃）. The genetic analysis indicated that this lesion-mimic phenotype is controlled by a single locus recessive nuclear gene. Furthermore, by using simple sequence repeat markers and an F2 segregating population derived from two crosses of Ims1 ×93-11 and Ims1 ×Pei＇ai 64S, the Imsl gene was mapped between markers Indel1 and MM0112-4 with a physical distance of 400 kb on chromosome 6 in rice.
文摘Phenotypical, cytological and molecular responses of rice to the fungus Magnaporthe grisea were studied using rice cultivars and lesion mimic plants. The cultivar Katy was susceptible to several virulent M. grisea isolates, and a Sekiguchi like-lesion mimic mutant of Katy （LmmKaty） showed enhanced resistance to these isolates. Lesion mimic phenotype of LmmKaty was rapidly induced by virulent M. grisea isolates or by avirulent ones only at high levels of inoculum. Autofluorescence （a sign of an active defense response） was visible under ultraviolet light 24 h after localized inoculation in the incompatible interaction, whereas, not evident in the compatible interaction. Autofluorescence was also observed in LmmKaty 20 h after pathogen inoculation, indicating that rapid cell death is a mechanism of LmmKaty to restrict pathogen invasion. Rapid accumulations of defense related （DR） gene transcripts, phenylalanine ammonia lyase and β-glucanase, were observed beginning at 6 h and were obvious at 16 h and 24 h after inoculation in an incompatible interaction. Rapid transcript accumulations of PR-1 and chitinase had occurred by 24 h after inoculation in an incompatible interaction. Accumulations of these transcripts were delayed in the compatible interaction. These results indicate that host active defense responses occur 24 h after pathogen inoculation and that LmmKaty exhibits enhanced resistance to M. grisea. It is suggested that the autofluorescence and expression of the DR genes after heavy inoculation are important cytological and molecular markers respectively for early determination of the host response to M. grisea in the rice blast system.
文摘通过筛选籼稻恢复系明恢86的组培变异后代,获得1个类病斑及早衰突变体lms1(lesion mimic and senescence 1)。lms1植株生长至拔节期开始在叶片上出现黄褐色小斑点,随后斑点逐渐扩展至大部分叶片和茎组织;生长至抽穗期后呈现早衰,穗、茎、叶明显干枯,并快速衰亡。RT-PCR分析表明,在呈现类病斑性状叶片组织的lsm1中,病程相关基因PBZ1、PAL1表达明显高于其在野生型叶片组织中的水平。遗传分析表明,lms1的突变性状受单隐性核基因控制。利用9311与lms1配置的F2及F3群体进行基因定位,将lms1基因定位在水稻第11染色体长臂末端。
