Evidence for rice Heading date 16 contribution to yield increase under low-nutrient conditions
Evidence for rice Heading date 16 contribution to yield increase under low-nutrient conditions
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DOI：
10.1080/00380768.2019.1647081
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发表时间：
2019-10
影响因子：
2
通讯作者：
Nobuhiro Tanaka;S. Yoshida;H. Takagi;R. Terauchi;A. Shimizu;T. Fujiwara
中科院分区：
文献类型：
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作者：
Nobuhiro Tanaka;S. Yoshida;H. Takagi;R. Terauchi;A. Shimizu;T. Fujiwara
选育耐低营养条件的水稻新品种是节约商品肥料使用的一种解决方案。我们分离出hiomebore EMS突变体520-6。520-6的幼苗生长对低养分供应，特别是低磷供应具有耐受能力，遗传图谱显示520-6的Os03g0793500第9外显子存在非同义取代。Os03g0793500报道为head date 16 (Hd16)/Early flowing1 (EL1)，与水稻开花途径有关。Hd16/EL1编码酪蛋白激酶1蛋白，磷酸化花抑制因子Ghd7和水稻DELLA蛋白细长水稻1 （SLR1）。520-6携带与“光”相同的非功能性Hd16等位基因，亲本品种Hitomebore携带与“日本裸”相同的功能性Hd16等位基因。与Hitomebore相比，在520-6中GA生物合成相关基因OsGA2ox3的mRNA积累量增加，表明Hd16参与了GA生物合成基因的反馈调控。无功能Hd16等位基因的520-6和近等基因系（NIL）分别在宫城县鹿田和滋贺县鹤根低氮无肥稻田表现出较高的秸秆重和穗重。此外，Hd16无功能等位基因的植株在所有试验田均表现为晚花表型。这些结果表明，Hd16的破坏通过正向调节GA信号和延迟开花来促进水稻生长，从而在低营养条件下提高水稻产量。
ABSTRACT Breeding new rice cultivars that are tolerant to low-nutrient condition is a solution to saving the usage of commercial fertilizer. We isolated Hitomebore EMS mutant, 520-6. Seedling growth of 520-6 is tolerant to low-nutrient supply, especially to low phosphorus (low P) supply and genetic mapping revealed the existence of nonsynonymous substitution within Os03g0793500 9th exon in 520-6. Os03g0793500 is reported as Heading date 16 (Hd16)/Early flowering1 (EL1), which is related with the rice flowering pathway. Hd16/EL1 encodes a casein kinase-I protein, and phosphorylates the floral repressor Ghd7 and the rice DELLA protein Slender rice 1 (SLR1). 520-6 carries the same nonfunctional Hd16 allele to that of Koshihikari, and the parental cultivar, Hitomebore, carries the functional Hd16 allele, as with Nipponbare. mRNA accumulation of GA-biosynthesis-related gene, OsGA2ox3 was enhanced in 520-6 compared with Hitomebore, indicating that Hd16 takes a part in feedback regulation of the GA biosynthetic gene. 520-6 and near-isogenic line (NIL) with nonfunctional Hd16 allele showed heavy straw weight and panicle weight in paddy fields with low nitrogen input and no fertilizer application in Kashimadai at Miyagi prefecture and Hikone at Shiga prefecture, respectively. In addition, plants with nonfunctional Hd16 allele showed late flowering phenotype in all tested fields. These results imply that disruption of Hd16 contributes to the improvement of rice growth by positively regulating GA signaling and late flowering, which resulted in increased rice yield under low-nutrient conditions.