Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivati...Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice(DSR) production.This study used a permanent mapping population with 144 recombinant inbred lines(RILs) and 2 828 bin-markers to detect quantitative trait loci(QTLs) associated with mesocotyl length in 2019 and 2020.The mesocotyl lengths of the rice RILs and their parents,Lijiangxintuanheigu(LTH) and Shennong 265(SN265),were measured in a growth chamber at 30°C in a dark environment.A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2),2(4),3(2),4,5,6,7,9,11(2),and 12.Seven of these QTLs,including qML1a,qML1b,qML2d,qML3a,qML3b,qML5,and qML11b,were reproducibly detected in both years via the interval mapping method.The major QTL,qML3a,was reidentified in two years via the composite interval mapping method.A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb,respectively.Thirteen predicted genes within a relatively small genetic interval(88.18 kb) of the major mesocotyl elongation QTL,qML3a,were more thoroughly analyzed.Finally,the coding DNA sequence variations among SN265,LTH,and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.In conclusion,these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.展开更多
东北地区是全球气候变暖趋势最为显著的地区之一,研究预期增温对东北水稻氮素吸收利用的影响,可为区域水稻可持续生产与氮肥优化管理提供借鉴。本研究于2019—2020年在黑龙江省哈尔滨市设置田间开放式增温(free air temperature increas...东北地区是全球气候变暖趋势最为显著的地区之一,研究预期增温对东北水稻氮素吸收利用的影响,可为区域水稻可持续生产与氮肥优化管理提供借鉴。本研究于2019—2020年在黑龙江省哈尔滨市设置田间开放式增温(free air temperature increase,FATI)系统,大田与盆栽试验相结合,采用^(15)N同位素示踪技术,模拟预期增温(+1.5℃)对水稻产量、氮素利用以及氮肥去向的影响。结果表明,增温促进了水稻地上部干物质积累,与对照相比,大田与盆栽的水稻产量2年平均分别提高10.4%和10.8%;增温显著提高了水稻氮素吸收总量,与对照相比,2年平均增幅达21.3%,但增温处理的氮素籽粒利用效率呈降低趋势;增温处理下水稻从肥料中吸收的氮素显著下降,但从土壤中吸收的氮素显著增加31.1%,导致氮肥回收率降低12.5%,而氮肥损失率增加14.2%。总体来看,增温有增加水稻籽粒产量的趋势,但降低了水稻对肥料氮的吸收比例,导致氮素利用效率降低,氮肥损失率显著增加。在气候变暖背景下,建议合理增加水稻移栽密度,以充分利用温度升高对水稻产量的正向效应,适当减少氮肥施用量、优化氮肥运筹管理,提高水稻氮素利用效率。展开更多
基金supported by grants from the Natural Science Foundation of Heilongjiang Province, China (LH2020C098)the Fundamental Research Funds for the Research Institutes of Heilongjiang Province, China (CZKYF2020A001)+1 种基金the National Key Research and Development Program of China (2016YFD0300104)the Heilongjiang Province Agricultural Science and Technology Innovation Project, China (2020JCQN001, 2019JJPY007, 2020FJZX049, 2021QKPY009, 2021CQJC003)。
文摘Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice(DSR) production.This study used a permanent mapping population with 144 recombinant inbred lines(RILs) and 2 828 bin-markers to detect quantitative trait loci(QTLs) associated with mesocotyl length in 2019 and 2020.The mesocotyl lengths of the rice RILs and their parents,Lijiangxintuanheigu(LTH) and Shennong 265(SN265),were measured in a growth chamber at 30°C in a dark environment.A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2),2(4),3(2),4,5,6,7,9,11(2),and 12.Seven of these QTLs,including qML1a,qML1b,qML2d,qML3a,qML3b,qML5,and qML11b,were reproducibly detected in both years via the interval mapping method.The major QTL,qML3a,was reidentified in two years via the composite interval mapping method.A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb,respectively.Thirteen predicted genes within a relatively small genetic interval(88.18 kb) of the major mesocotyl elongation QTL,qML3a,were more thoroughly analyzed.Finally,the coding DNA sequence variations among SN265,LTH,and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.In conclusion,these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.
文摘东北地区是全球气候变暖趋势最为显著的地区之一,研究预期增温对东北水稻氮素吸收利用的影响,可为区域水稻可持续生产与氮肥优化管理提供借鉴。本研究于2019—2020年在黑龙江省哈尔滨市设置田间开放式增温(free air temperature increase,FATI)系统,大田与盆栽试验相结合,采用^(15)N同位素示踪技术,模拟预期增温(+1.5℃)对水稻产量、氮素利用以及氮肥去向的影响。结果表明,增温促进了水稻地上部干物质积累,与对照相比,大田与盆栽的水稻产量2年平均分别提高10.4%和10.8%;增温显著提高了水稻氮素吸收总量,与对照相比,2年平均增幅达21.3%,但增温处理的氮素籽粒利用效率呈降低趋势;增温处理下水稻从肥料中吸收的氮素显著下降,但从土壤中吸收的氮素显著增加31.1%,导致氮肥回收率降低12.5%,而氮肥损失率增加14.2%。总体来看,增温有增加水稻籽粒产量的趋势,但降低了水稻对肥料氮的吸收比例,导致氮素利用效率降低,氮肥损失率显著增加。在气候变暖背景下,建议合理增加水稻移栽密度,以充分利用温度升高对水稻产量的正向效应,适当减少氮肥施用量、优化氮肥运筹管理,提高水稻氮素利用效率。
