Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is the most serious disease of potato worldwide. The adoption of varieties with resistance genes, especially broad-spectrum resistance genes,...Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is the most serious disease of potato worldwide. The adoption of varieties with resistance genes, especially broad-spectrum resistance genes, is the most efficient approach to control late blight. Solanum demissum is a well-known wild potato species from which 11 race-specific resistance genes have been identified, however, no broad-spectrum resistance genes like RB have been reported in this species. Here, we report a novel reisistance locus from S. demissum that potentially confer broad-spectrum resistance to late blight. A small segregating population of S. demissum were assessed for resistance to aggressive P. infestans isolates（race 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11）. This coupled with nucleotide binding site（NBS） profiling analyses, led to the identification of three fragments that linked to the potential candidate resistance gene（s）. Cloning and sequence analysis of these fragments suggested that the identified resistance gene locus is located in the region containing R2 resistance gene at chromosome 4. Based on the sequences of the cloned fragments, a co-segregating sequence characterized amplified region（SCAR） marker, RDSP, was developed. The newly identified marker RDSP will be useful for marker assisted breeding and further cloning of this potential resistance gene locus.展开更多
为了研究120 t BOF-LF-RH-160 mm×160 mm坯CC工艺生产的铝脱氧20钢(/%:0.13-0.23C,0.17~0.37Si,0.35~0.65Mn,≤0.035P,≤0.035S,0.020~0.050Al)中非金属夹杂物的控制技术,对LF精炼过程中脱氧剂加入时机进行调整,并对精炼过程中非...为了研究120 t BOF-LF-RH-160 mm×160 mm坯CC工艺生产的铝脱氧20钢(/%:0.13-0.23C,0.17~0.37Si,0.35~0.65Mn,≤0.035P,≤0.035S,0.020~0.050Al)中非金属夹杂物的控制技术,对LF精炼过程中脱氧剂加入时机进行调整,并对精炼过程中非金属夹杂物类型与夹杂物数量进行分析。结果表明,转炉出钢后采用铝块脱氧,LF精炼进站非金属夹杂物主要为Al_(2)O_(3),精炼结束前部分夹杂物由Al_(2)O_(3)转变为Al_(2)O_(3)·CaO,RH结束后非金属夹杂物密度3~4个/mm^(2),铸坯氧含量(7.48-8.18)×10^(-6);而转炉出钢后采用硅锰进行脱氧,精炼结束前采用铝线,精炼过程中夹杂物主要为MnO·SiO_(2),CaO含量小于5%,精炼结束非金属夹杂物控制为Al_(2)O_(3),RH真空处理后,非金属夹杂物密度小于1.5个/mm^(2),铸坯氧含量(4.94~5.53)×10^(-6)。因此,针对采用"BOF-LF-RH-CC"工艺流程生产的含铝钢,提出精炼结束前将非金属夹杂物控制为Al_(2)O_(3),同时运用RH真空高效去除夹杂物,以提高钢水的洁净度。展开更多
基金supported by the Key Laboratory of Biology and Genetic Improvement of Tuber and Root Crop, Ministry of Agriculture, P.R.Chinafunded by the National Natural Science Foundation of China (NSFC, 31000738)
文摘Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is the most serious disease of potato worldwide. The adoption of varieties with resistance genes, especially broad-spectrum resistance genes, is the most efficient approach to control late blight. Solanum demissum is a well-known wild potato species from which 11 race-specific resistance genes have been identified, however, no broad-spectrum resistance genes like RB have been reported in this species. Here, we report a novel reisistance locus from S. demissum that potentially confer broad-spectrum resistance to late blight. A small segregating population of S. demissum were assessed for resistance to aggressive P. infestans isolates（race 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11）. This coupled with nucleotide binding site（NBS） profiling analyses, led to the identification of three fragments that linked to the potential candidate resistance gene（s）. Cloning and sequence analysis of these fragments suggested that the identified resistance gene locus is located in the region containing R2 resistance gene at chromosome 4. Based on the sequences of the cloned fragments, a co-segregating sequence characterized amplified region（SCAR） marker, RDSP, was developed. The newly identified marker RDSP will be useful for marker assisted breeding and further cloning of this potential resistance gene locus.
文摘为了研究120 t BOF-LF-RH-160 mm×160 mm坯CC工艺生产的铝脱氧20钢(/%:0.13-0.23C,0.17~0.37Si,0.35~0.65Mn,≤0.035P,≤0.035S,0.020~0.050Al)中非金属夹杂物的控制技术,对LF精炼过程中脱氧剂加入时机进行调整,并对精炼过程中非金属夹杂物类型与夹杂物数量进行分析。结果表明,转炉出钢后采用铝块脱氧,LF精炼进站非金属夹杂物主要为Al_(2)O_(3),精炼结束前部分夹杂物由Al_(2)O_(3)转变为Al_(2)O_(3)·CaO,RH结束后非金属夹杂物密度3~4个/mm^(2),铸坯氧含量(7.48-8.18)×10^(-6);而转炉出钢后采用硅锰进行脱氧,精炼结束前采用铝线,精炼过程中夹杂物主要为MnO·SiO_(2),CaO含量小于5%,精炼结束非金属夹杂物控制为Al_(2)O_(3),RH真空处理后,非金属夹杂物密度小于1.5个/mm^(2),铸坯氧含量(4.94~5.53)×10^(-6)。因此,针对采用"BOF-LF-RH-CC"工艺流程生产的含铝钢,提出精炼结束前将非金属夹杂物控制为Al_(2)O_(3),同时运用RH真空高效去除夹杂物,以提高钢水的洁净度。
