Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine map- p...Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine map- ped or cloned, the underlying genetic architecture remains unclear. We performed a genome-wide associ- ation study on stigma exsertion and related floral traits using 6.5 million SNPs characterized in 533 diverse accessions of Oryza sativa. We identified 23 genomic loci that are significantly associated with stigma exsertion and related traits, three of which are co-localized with three major grain size genes GS3, GW5, and GW2. Further analyses indicated that these three genes affected the stigma exsertion by controlling the size and shape of the spikelet and stigma. Combinations of GS3 and GW5 largely defined the levels of stigma exsertion and related traits. Selections of these two genes resulted in specific distributions of floral traits among subpopulations of O. sativa. The low stigma exsertion combination gw5GS3 existed in half of the cultivated rice varieties; therefore, introducing the GW5gs3 combination into male sterile lines is of high potential for improving the seed production of hybrid rice.展开更多
With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase poll...With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase pollen reception and promote female reproductive success.The aim of this study was to investigate the role of stigma exsertion on spikelet fertility at high temperatures.Five rice cultivars(Liangyoupeijiu, Shanyou 63, Huanghuazhan, Nagina 22, and IR64) with differing degrees of stigma exsertion were cultivated and exposed to high temperature at anthesis.Heat-tolerant cultivars did not always show a high percentage of spikelets with exserted stigmas, and vice versa.Irrespective of the presence of more pollen grains on exserted stigmas, spikelets with exserted stigmas did not show greater spikelet fertility than spikelets with fewer exserted stigmas or hidden stigmas under heat stress.GA3 application augmented the percentage of spikelets with exserted stigmas;however, it did not increase spikelet fertility under heat stress.Spikelet fertility of whole panicles was negatively correlated with the percentage of spikelets with exserted stigmas, but positively with that with hidden stigmas.Viability of the hidden stigmas was less reduced than that of exserted stigmas under heat stress, suggesting that hidden stigmas have an advantage in maintaining viability.Heat stress delayed anther dehiscence and reduced the viabilities of both exserted stigmas and pollens, thereby causing low spikelet fertility.Together, these results suggest that high spikelet fertility does not depend on stigma exsertion and that enclosed stigma generally contributes to higher spikelet fertility and heat tolerance under high-temperature conditions during flowering in rice.展开更多
柱头外露作为提高作物异交率、制种纯度和降低制种成本的优良性状,在杂交制种中得到了广泛的利用。绿豆是一种闭花授粉的作物,被报道的柱头外露突变体很少。通过对冀绿7号的化学诱变,发现了1个柱头外露突变体se2,为明确该突变体柱头外...柱头外露作为提高作物异交率、制种纯度和降低制种成本的优良性状,在杂交制种中得到了广泛的利用。绿豆是一种闭花授粉的作物,被报道的柱头外露突变体很少。通过对冀绿7号的化学诱变,发现了1个柱头外露突变体se2,为明确该突变体柱头外露的分子机制,对该突变体及其野生型冀绿7号即将开放的花蕾进行了转录组测序(RNA-seq)分析。根据差异倍数|log2(Fold Change)|≥1,P≤0.05的标准筛选,在se2中共得到572个差异表达基因(differentially expressed genes,DEGs),其中262个DEGs上调,310个DEGs下调。在基因本体(gene ontology,GO)数据库中,差异表达基因显著富集到代谢和生物合成等生物过程,定位在质外体和细胞壁、细胞膜等区域,与结合、氧化还原等分子功能有关。在京都基因与基因组百科全书(kyoto encyclopedia of genes and genome,KEGG)数据库中,差异表达基因显著富集在植物激素信号传导、次生代谢物生物合成等通路。功能注释发现许多有关细胞壁合成和代谢、细胞分裂和细胞扩张、植物激素相关的基因,因此推测se2突变体中龙骨瓣的细胞分裂、细胞扩张以及植物激素信号传导过程受到影响,从而导致了柱头外露。本研究为今后探究绿豆柱头外露的分子机制以及该性状在绿豆杂种优势中的利用奠定了基础。展开更多
Stigma exsertion in male sterile lines of hybrid rice is important for seed yield.In the present study, ZS616 [Oryza sativa subsp.Xian(indica)], a male sterile line with a stigma exsertion rate(SER) as high as 94.5%, ...Stigma exsertion in male sterile lines of hybrid rice is important for seed yield.In the present study, ZS616 [Oryza sativa subsp.Xian(indica)], a male sterile line with a stigma exsertion rate(SER) as high as 94.5%, was crossed to DS552, a japonica line with almost no exserted stigmas.F3 plants with extremely low and high SER were sequenced to identify SER-associated quantitative trait loci(QTL).A major QTL for SER, qSER-3.1, was identified along with other QTL on chromosome 3 in a 3.9 Mb region.A total of 307 nonsynonymous single-nucleotide polymorphisms(SNPs) and 27 frame-shift insertion/deletions(InDels)differentiating ZS616 and DS552 were identified in the region containing qSER-3.1.Most SNPs(294) and InDels(25) were excluded after further analysis because they were shared by ZS616 and low(<2.0%) SER accessions in the Huazhong Agricultural University(HAU) core rice collection.Association analysis using the full HAU collection identified a 17-bp InDel in OS03 G0689400 as the most likely causal genetic variant underlying qSER-3.1.ZS616-type accessions(n = 54, with the 17-bp insertion) in the HAU collection had minimum(16.5%)and mean(39.6%) SERs significantly greater than those(n = 424) without the insertion(with minimum and mean SERs of 0.2% and 20.6%, respectively).Thus, this study identified a major QTL for stigma exsertion and revealed the mutation in a candidate gene for the QTL.展开更多
文摘Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine map- ped or cloned, the underlying genetic architecture remains unclear. We performed a genome-wide associ- ation study on stigma exsertion and related floral traits using 6.5 million SNPs characterized in 533 diverse accessions of Oryza sativa. We identified 23 genomic loci that are significantly associated with stigma exsertion and related traits, three of which are co-localized with three major grain size genes GS3, GW5, and GW2. Further analyses indicated that these three genes affected the stigma exsertion by controlling the size and shape of the spikelet and stigma. Combinations of GS3 and GW5 largely defined the levels of stigma exsertion and related traits. Selections of these two genes resulted in specific distributions of floral traits among subpopulations of O. sativa. The low stigma exsertion combination gw5GS3 existed in half of the cultivated rice varieties; therefore, introducing the GW5gs3 combination into male sterile lines is of high potential for improving the seed production of hybrid rice.
基金This work was supported by the Grants from Chinese Ministry of Agriculture (No. 948-2001-101), Chinese Ministry of Science and Technology (No. 2003AA207010), Shanghai Municipal Science and Technology Commission (No. 02ZC14082), and the Rocke-feller Foundation.
基金supported by the National Natural Science Foundation of China (30971707, 31361140368)the National Key Research and Development Program of China (2017YFD0300100)+2 种基金the Natural Science Foundation of Jiangsu Province (BK20180537)the China Postdoctoral Science Foundation (2017M621757)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase pollen reception and promote female reproductive success.The aim of this study was to investigate the role of stigma exsertion on spikelet fertility at high temperatures.Five rice cultivars(Liangyoupeijiu, Shanyou 63, Huanghuazhan, Nagina 22, and IR64) with differing degrees of stigma exsertion were cultivated and exposed to high temperature at anthesis.Heat-tolerant cultivars did not always show a high percentage of spikelets with exserted stigmas, and vice versa.Irrespective of the presence of more pollen grains on exserted stigmas, spikelets with exserted stigmas did not show greater spikelet fertility than spikelets with fewer exserted stigmas or hidden stigmas under heat stress.GA3 application augmented the percentage of spikelets with exserted stigmas;however, it did not increase spikelet fertility under heat stress.Spikelet fertility of whole panicles was negatively correlated with the percentage of spikelets with exserted stigmas, but positively with that with hidden stigmas.Viability of the hidden stigmas was less reduced than that of exserted stigmas under heat stress, suggesting that hidden stigmas have an advantage in maintaining viability.Heat stress delayed anther dehiscence and reduced the viabilities of both exserted stigmas and pollens, thereby causing low spikelet fertility.Together, these results suggest that high spikelet fertility does not depend on stigma exsertion and that enclosed stigma generally contributes to higher spikelet fertility and heat tolerance under high-temperature conditions during flowering in rice.
文摘柱头外露作为提高作物异交率、制种纯度和降低制种成本的优良性状,在杂交制种中得到了广泛的利用。绿豆是一种闭花授粉的作物,被报道的柱头外露突变体很少。通过对冀绿7号的化学诱变,发现了1个柱头外露突变体se2,为明确该突变体柱头外露的分子机制,对该突变体及其野生型冀绿7号即将开放的花蕾进行了转录组测序(RNA-seq)分析。根据差异倍数|log2(Fold Change)|≥1,P≤0.05的标准筛选,在se2中共得到572个差异表达基因(differentially expressed genes,DEGs),其中262个DEGs上调,310个DEGs下调。在基因本体(gene ontology,GO)数据库中,差异表达基因显著富集到代谢和生物合成等生物过程,定位在质外体和细胞壁、细胞膜等区域,与结合、氧化还原等分子功能有关。在京都基因与基因组百科全书(kyoto encyclopedia of genes and genome,KEGG)数据库中,差异表达基因显著富集在植物激素信号传导、次生代谢物生物合成等通路。功能注释发现许多有关细胞壁合成和代谢、细胞分裂和细胞扩张、植物激素相关的基因,因此推测se2突变体中龙骨瓣的细胞分裂、细胞扩张以及植物激素信号传导过程受到影响,从而导致了柱头外露。本研究为今后探究绿豆柱头外露的分子机制以及该性状在绿豆杂种优势中的利用奠定了基础。
基金supported by the Zhejiang Provincial S&T Project on Breeding of Agricultural (Food) Crops (2016C020502)the Major Science and Technology Innovation Program of Hangzhou, China (2015012A09)
文摘Stigma exsertion in male sterile lines of hybrid rice is important for seed yield.In the present study, ZS616 [Oryza sativa subsp.Xian(indica)], a male sterile line with a stigma exsertion rate(SER) as high as 94.5%, was crossed to DS552, a japonica line with almost no exserted stigmas.F3 plants with extremely low and high SER were sequenced to identify SER-associated quantitative trait loci(QTL).A major QTL for SER, qSER-3.1, was identified along with other QTL on chromosome 3 in a 3.9 Mb region.A total of 307 nonsynonymous single-nucleotide polymorphisms(SNPs) and 27 frame-shift insertion/deletions(InDels)differentiating ZS616 and DS552 were identified in the region containing qSER-3.1.Most SNPs(294) and InDels(25) were excluded after further analysis because they were shared by ZS616 and low(<2.0%) SER accessions in the Huazhong Agricultural University(HAU) core rice collection.Association analysis using the full HAU collection identified a 17-bp InDel in OS03 G0689400 as the most likely causal genetic variant underlying qSER-3.1.ZS616-type accessions(n = 54, with the 17-bp insertion) in the HAU collection had minimum(16.5%)and mean(39.6%) SERs significantly greater than those(n = 424) without the insertion(with minimum and mean SERs of 0.2% and 20.6%, respectively).Thus, this study identified a major QTL for stigma exsertion and revealed the mutation in a candidate gene for the QTL.
