Control of Tiller Growth of Rice by OsSPL14 and Strigolactones, Which Work in Two Independent Pathways

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Le Luo, Weiqiang Li, Kotaro Miura, Motoyuki Ashikari, Junko Kyozuka
Plant and Cell Physiology, 2012, 53(10): 1793-1801  DOI: 10.1093/pcp/pcs122     追溯原文......本站官方QQ群:62473826
Plastochron; Rice; SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL); Strigolactone (SL); Tiller

The architecture of rice is greatly influenced by the growth of tillers, i.e. vegetative shoot branches. OsSPL14, a member of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, and strigolactones (SLs) are known to suppress outgrowth of tiller buds. OsSPL14 also regulates panicle development. We show that OsSPL14 mRNA accumulates in leaf primordia during the vegetative phase and in the primordia of bracts, or modified leaves, in the panicles, but not in the meristems. OsSPL14 is a target of miR156, and accumulation of OsSPL14 transcripts is negatively regulated by miR156. The enhancement of the expression level of OsSPL14 by the introduction of the mOsSPL14 gene, in which the miR156 cleavage site is mutated, resulted in an increase in the plastochron, an acceleration of flowering and a decrease in tiller number in the wild type and in dwarf10-2, an SL-deficient mutant. Our analysis suggests that OsSPL14 and SLs function in parallel pathways to suppress tiller growth. SLs exuded from roots trigger germination of root parasitic plants that can cause severe damage to crop productivity. SL-deficient mutants, however, exhibit an excess branching phenotype which is usually undesirable for productivity. Our results indicate that OsSPL14 can be used to manipulate the branching patterns of SL-deficient mutants. We also confirmed that this strategy is applicable to Arabidopsis. A greater understanding of the OsSPL14 and SL pathways and their interactions may help in the production of root parasite-resistant crops.

OsSPL14和独脚金内酯通过两个独立的途径控制水稻分蘖生长

水稻株型很大程度上受分蘖(地上营养枝)生长的影响。一个类-Squamosa启动子结合蛋白(SPL)基因家族成员OsSPL14,和独脚金内酯能抑制分蘖芽的长出。OsSPL14也调控穗的发育。我们研究发现OsSPL14 mRNA在营养生长期的叶原基、苞叶原基、变态叶和穗中积累,但是不在分生组织中积累。OsSPL14miR156的标靶,OsSPL14转录产物的积累受miR156的负调控。转入miR156切割位点突变的mOsSPL14基因,OsSPL14基因表达水平增强,导致野生型和SL-缺陷突变体dwarf10-2的叶原基间隔期增长,开花提前,分蘖数目减少。我们的分析表明OsSPL14和SLs在抑制分蘖生长上,是在并行的途径上起作用。根释放的SLs诱发根寄生植物的萌发,这能引起作物产量的严重损失。然而,SL缺陷突变体表现出多分蘖的表型,这对产量而言通常是无效的。我们的结果提示OsSPL14能够用来调控SL缺陷突变体的分蘖模式,我们也证实这一策略在拟南芥上同样适用。对于OsSPL14和SL途径及其相互作用更进一步的了解,可能有助于抗根寄生作物的生产。


基因列表
  Squamosa启动子结合蛋白基因 OsSPL14; IPA1;WFP