The rice mutant ossac4(starch accumulating 4)was raised from seeds of the rice(Oryza sativa L.)indica maintainer line Xinong 1B treated with ethyl methanesulfonate.The distal and medial portions of the second leaf dis...The rice mutant ossac4(starch accumulating 4)was raised from seeds of the rice(Oryza sativa L.)indica maintainer line Xinong 1B treated with ethyl methanesulfonate.The distal and medial portions of the second leaf displayed premature senescence in the ossac4 mutant at the four-leaf stage.Physiological and biochemical analysis,and cytological examination revealed that the ossac4 mutant exhibited the premature leaf senescence phenotype.At the four-leaf stage,the leaves of the ossac4 mutant exhibited significantly increased contents of starch compared with those of the wild type(WT).Quantitative real-time PCR analysis showed that the expression levels of photosynthesis-associated genes were down-regulated and the expression levels of glucose metabolism-associated genes were abnormal.Genetic analysis indicated that the ossac4 mutation was controlled by a single recessive nuclear gene.The OsSAC4 gene was localized to a 322.7-kb interval between the simple-sequence repeat marker XYH11-90 and the single-nucleotide polymorphism marker SNP5300 on chromosome 11.The target interval contained 20 annotated genes.The present results demonstrated that ossac4 represents a novel starch accumulation and premature leaf senescence mutant,and lays the foundation for cloning and functional analysis of OsSAC4.展开更多
The marginal areas of the Tibetan Plateau have great vertical altitude gradient and abundant vegetation, they are therefore the ideal places for investigating the relationships among carbon isotope composition(δ^(13)...The marginal areas of the Tibetan Plateau have great vertical altitude gradient and abundant vegetation, they are therefore the ideal places for investigating the relationships among carbon isotope composition(δ^(13)C) of modern soils, vegetation and environmental factors, which would be very useful for the reconstructions of both paleovegetation and paleoclimate. In this paper, modern soil samples collected in different vegetation vertical zones along 4km elevation gradient in the eastern margin of the Tibetan Plateau were analyzed for their carbon isotope composition. The results show that the modern soils in different vegetation vertical zones show apparent difference of δ^(13)C values, which get heavier in the sequence of mixed evergreen and deciduous broad-leaved forest(-27.28‰ on average), evergreen broad-leaved forest(-27.25‰), subalpine shrub-meadow(-25.81‰), subalpine coniferous forest(-25.81‰), alpine bush-meadow(-25.16‰), and drought-enduring shrub(-24.07‰). 1800 m and 3500 m are two critical points for the δ^(13)C values with respect to altitude. Specifically, the δ^(13)C values decrease with increasing altitude below both points while increasing with increasing altitude above both points. Further analyses indicate that the declining δ^(13)C values are mainly controlled by the decreasing proportion of C4 plants with elevation and the increasing δ^(13)C values are attributed to the plant physic-morphological adaptation to the alpine environment. In the absence of drought stress, temperature is the main controlling factor for the carbon isotopic variations with altitude gradient.展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFD0100201)the Project of Chongqing Science&Technology Commission Grants,China(CSTCCXLJRC201713and CSTC2016SHMS-ZTZx0017)and the Fundamental Research Funds for the Central Universities,China(XDJK2017C030).
文摘The rice mutant ossac4(starch accumulating 4)was raised from seeds of the rice(Oryza sativa L.)indica maintainer line Xinong 1B treated with ethyl methanesulfonate.The distal and medial portions of the second leaf displayed premature senescence in the ossac4 mutant at the four-leaf stage.Physiological and biochemical analysis,and cytological examination revealed that the ossac4 mutant exhibited the premature leaf senescence phenotype.At the four-leaf stage,the leaves of the ossac4 mutant exhibited significantly increased contents of starch compared with those of the wild type(WT).Quantitative real-time PCR analysis showed that the expression levels of photosynthesis-associated genes were down-regulated and the expression levels of glucose metabolism-associated genes were abnormal.Genetic analysis indicated that the ossac4 mutation was controlled by a single recessive nuclear gene.The OsSAC4 gene was localized to a 322.7-kb interval between the simple-sequence repeat marker XYH11-90 and the single-nucleotide polymorphism marker SNP5300 on chromosome 11.The target interval contained 20 annotated genes.The present results demonstrated that ossac4 represents a novel starch accumulation and premature leaf senescence mutant,and lays the foundation for cloning and functional analysis of OsSAC4.
基金supported by the National Natural Science Foundation of China (grant nos. 41888101, 41907377 and 41772383)the Special Fund for Basic Scientific Research of China University of Geosciences (grant no. 53200859557)。
文摘The marginal areas of the Tibetan Plateau have great vertical altitude gradient and abundant vegetation, they are therefore the ideal places for investigating the relationships among carbon isotope composition(δ^(13)C) of modern soils, vegetation and environmental factors, which would be very useful for the reconstructions of both paleovegetation and paleoclimate. In this paper, modern soil samples collected in different vegetation vertical zones along 4km elevation gradient in the eastern margin of the Tibetan Plateau were analyzed for their carbon isotope composition. The results show that the modern soils in different vegetation vertical zones show apparent difference of δ^(13)C values, which get heavier in the sequence of mixed evergreen and deciduous broad-leaved forest(-27.28‰ on average), evergreen broad-leaved forest(-27.25‰), subalpine shrub-meadow(-25.81‰), subalpine coniferous forest(-25.81‰), alpine bush-meadow(-25.16‰), and drought-enduring shrub(-24.07‰). 1800 m and 3500 m are two critical points for the δ^(13)C values with respect to altitude. Specifically, the δ^(13)C values decrease with increasing altitude below both points while increasing with increasing altitude above both points. Further analyses indicate that the declining δ^(13)C values are mainly controlled by the decreasing proportion of C4 plants with elevation and the increasing δ^(13)C values are attributed to the plant physic-morphological adaptation to the alpine environment. In the absence of drought stress, temperature is the main controlling factor for the carbon isotopic variations with altitude gradient.
