Graduate School of Life Sciences, Toyo University, Itakura-machi, Ora-gun, Gunma 374-0193, Japan.
Department of Applied Biosciences, Toyo University, Itakura-machi, Ora-gun, Gunma 374-0193, Japan.
Int J Mol Sci. 2018 Sep 6;19(9):2645. doi: 10.3390/ijms19092645.
Strigolactones (SLs), a group of plant hormones, induce germination of root-parasitic plants and inhibit shoot branching in many plants. Shoot branching is an important trait that affects the number and quality of flowers and fruits. Root-parasitic plants, such as spp., infect tomato roots and cause economic damage in Europe and North Africa-hence why resistant tomato cultivars are needed. In this study, we found defective mutants of Micro-Tom tomato () by the "targeting induced local lesions in genomes" (TILLING) method. The mutants showed excess branching, which was suppressed by exogenously applied SL. Grafting shoot scions of the mutants onto wild-type (WT) rootstocks restored normal branching in the scions. The levels of endogenous orobanchol and solanacol in WT were enough detectable, whereas that in the mutants were below the detection limit of quantification analysis. Accordingly, root exudates of the mutants hardly stimulated seed germination of root parasitic plants. In addition, SL deficiency did not critically affect the fruit traits of Micro-Tom. Using a rhizotron system, we also found that infection was lower in the mutants than in wild-type Micro-Tom because of the low germination. We propose that the mutants might be useful as new tomato lines resistant to .
独脚金内酯（SLs）是一组植物激素，它能诱导根寄生植物的萌发，并抑制许多植物的侧芽分枝。侧芽分枝是一个重要的性状，影响花和果实的数量和质量。根寄生植物，如 ，感染番茄根系，并在欧洲和北非造成经济损失，因此需要具有抗性的番茄品种。在这项研究中，我们通过“靶向诱导基因组局部突变”（TILLING）的方法发现了微型番茄（）的缺陷突变体。这些突变体表现出过度分枝的现象，而外源施加 SL 则可以抑制这种现象。将 突变体的茎尖嫁接到野生型（WT）根砧上，可以使茎尖恢复正常的分枝。WT 中内源或根醇和茄醇的水平可被检测到，而 突变体中的水平低于定量分析的检测限。因此， 突变体的根分泌物几乎不能刺激根寄生植物的种子萌发。此外，SL 缺乏对微型番茄的果实特性没有显著影响。使用根室系统，我们还发现由于萌发率较低， 突变体中的 感染比野生型微型番茄要低。我们提出，由于萌发率低， 突变体可能作为新的番茄品系对 具有抗性。
