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.
水稻株型很大程度上受分蘗（地上營(yíng)養(yǎng)枝）生長(zhǎng)的影響。一個(gè)類-Squamosa啟動(dòng)子結(jié)合蛋白（SPL）基因家族成員OsSPL14，和獨(dú)腳金內(nèi)酯能抑制分蘗芽的長(zhǎng)出。OsSPL14也調(diào)控穗的發(fā)育。我們研究發(fā)現(xiàn)OsSPL14 mRNA在營(yíng)養(yǎng)生長(zhǎng)期的葉原基、苞葉原基、變態(tài)葉和穗中積累，但是不在分生組織中積累。OsSPL14是miR156的標(biāo)靶，OsSPL14轉(zhuǎn)錄產(chǎn)物的積累受miR156的負(fù)調(diào)控。轉(zhuǎn)入miR156切割位點(diǎn)突變的mOsSPL14基因，OsSPL14基因表達(dá)水平增強(qiáng)，導(dǎo)致野生型和SL-缺陷突變體dwarf10-2的葉原基間隔期增長(zhǎng)，開(kāi)花提前，分蘗數(shù)目減少。我們的分析表明OsSPL14和SLs在抑制分蘗生長(zhǎng)上，是在并行的途徑上起作用。根釋放的SLs誘發(fā)根寄生植物的萌發(fā)，這能引起作物產(chǎn)量的嚴(yán)重?fù)p失。然而，SL缺陷突變體表現(xiàn)出多分蘗的表型，這對(duì)產(chǎn)量而言通常是無(wú)效的。我們的結(jié)果提示OsSPL14能夠用來(lái)調(diào)控SL缺陷突變體的分蘗模式，我們也證實(shí)這一策略在擬南芥上同樣適用。對(duì)于OsSPL14和SL途徑及其相互作用更進(jìn)一步的了解，可能有助于抗根寄生作物的生產(chǎn)。