Dependence of root parasitic plants on host-derived strigolactones

Strigolactones(SLS)是一类调节植物结构的植物激素，也是共生和寄生的根源信号。本研究探讨了由SLS引发种子萌发的根寄生植物Striga hermonthica是否产生SLS，以及寄主提供的SLS对寄生虫形态的影响。生长在琼脂上的Striga植物的SLS水平低于LC-MS分析的检测限，而Striga植物的SLS光谱与其各自寄主的SLS光谱一致。生长在SL缺陷型水稻突变体上的Striga植株形成了形状和数量不正常的叶片。这些结果表明，Striga的SL产量非常有限，寄主植物提供的SLS不仅调节Striga种子的萌发，而且还调节寄生虫的形态。

Strigolactones (SLs) are a class of plant hormones that regulate plant architecture as well as being known as root-derived signals for symbiosis and parasitism. This study examined 1) whether Striga hermonthica, a root parasitic plant, whose seed germination is triggered by SLs, produces SLs, and 2) the effect of SLs provided by the host on morphology of the parasite. The level of SLs in Striga plants growing on agar, independent of host, was below the detection limit of LC-MS analysis while SL spectra detected in Striga plants were consistent with those in their respective hosts. Striga plants growing on SL-deficient rice mutants formed leaves abnormal in shape and number. These results suggest that SL production in Striga, if any, is very limited and that SLs provided by host plants regulate not only germination of Striga seeds but also the parasite morphology.