Contribution of strigolactones to the inhibition of tiller bud outgrowth under phosphate deficiency in rice.
Contribution of strigolactones to the inhibition of tiller bud outgrowth under phosphate deficiency in rice.
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DOI：
10.1093/pcp/pcq084
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发表时间：
2010-07
影响因子：
4.9
通讯作者：
Yamaguchi S
中科院分区：
文献类型：
--
作者：
Umehara M;Hanada A;Magome H;Takeda-Kamiya N;Yamaguchi S
独脚金内酯（SL）或SL衍生的代谢产物最近已被证明是腋芽生长的内源性抑制剂。从根中释放的SL诱导丛枝菌根（AM）真菌的菌丝分枝，促进宿主植物吸收无机营养物质，如磷酸盐（Pi）和硝酸盐。以往的研究表明，根分泌物中的SL水平被磷饥饿高度升高，这可能有助于成功的共生与AM真菌在根际。然而，如何内源性SL水平升高的Pi饥饿有助于其激素作用一直是未知的。在这里，我们表明，分蘖芽生长在野生型水稻幼苗抑制，而根2′-表-5-脱氧独脚金醇（epi-5DS）水平升高，响应于介质中的Pi浓度降低。然而，抑制分蘖芽生长在磷缺乏下不发生在SL-缺陷和不敏感的突变体。我们还表明，外源SL的反应略有增加，磷缺乏。当Pi饥饿的幼苗转移到Pi充足的媒体，分蘖芽生长诱导根epi-5DS水平下降。综上所述，这些结果表明，高SL水平的磷饥饿有助于抑制水稻分蘖芽的生长。我们推测，SL在适应磷缺乏中起着双重作用;一个作为根际信号，以最大限度地提高磷的收购和其他作为内源激素或其生物合成前体，以优化芽分枝有效的磷利用率AM真菌共生。
Strigolactones (SLs) or SL-derived metabolite(s) have recently been shown to act as endogenous inhibitors of axillary bud outgrowth. SLs released from roots induce hyphal branching of arbuscular mycorrhizal (AM) fungi that facilitate the uptake of inorganic nutrients, such as phosphate (Pi) and nitrate, by the host plants. Previous studies have shown that SL levels in root exudates are highly elevated by Pi starvation, which might contribute to successful symbiosis with AM fungi in the rhizosphere. However, how endogenous SL levels elevated by Pi starvation contribute to its hormonal action has been unknown. Here, we show that tiller bud outgrowth in wild-type rice seedlings is inhibited, while root 2′-epi-5-deoxystrigol (epi-5DS) levels are elevated, in response to decreasing Pi concentrations in the media. However, the suppression of tiller bud outgrowth under Pi deficiency does not occur in the SL-deficient and -insensitive mutants. We also show that the responsiveness to exogenous SL is slightly increased by Pi deficiency. When Pi-starved seedlings are transferred to Pi-sufficient media, tiller bud outgrowth is induced following a decrease in root epi-5DS levels. Taken together, these results suggest that elevated SL levels by Pi starvation contribute to the inhibition of tiller bud outgrowth in rice seedlings. We speculate that SL plays a dual role in the adaptation to Pi deficiency; one as a rhizosphere signal to maximize AM fungi symbiosis for improved Pi acquisition and the other as an endogenous hormone or its biosynthetic precursor to optimize shoot branching for efficient Pi utilization.
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影响因子：
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