Niwa Tomoko, Suzuki Takamasa, Takebayashi Yumiko, Ishiguro Rie, Higashiyama Tetsuya, Sakakibara Hitoshi, Ishiguro Sumie
a Graduate School of Bio-agricultural Sciences , Nagoya University , Nagoya , Japan.
b College of Bioscience and Biotechnology , Chubu University , Kasugai , Japan.
Biosci Biotechnol Biochem. 2018 Feb;82(2):292-303. doi: 10.1080/09168451.2017.1422107.
Plants coordinate the timing of flower opening with pollen and gynoecium maturation to achieve successful pollination. However, little is known about how the coordination is executed. We found that flower bud development was paused immediately before flower opening in a jasmonic acid (JA)-insensitive tomato mutant, jai1-1. Phytohormone measurement and RNA analysis in flower buds revealed that newly synthesised JA peaked at two days before flower opening and the expression of a transcription factor gene SlMYB21 delayed in jai1-1. Buds of transgenic tomato plants expressing an artificial repressor, AtMYB24-SRDX, which was expected to impede the function of SlMYB21, aborted flower opening and resembled those of jai1-1. Furthermore, the AtMYB24-SRDX plants produced abnormal pollen grains deficient in germination and pistils that did not support pollen tube elongation. We concluded that JA facilitates the expression of SlMYB21, which coordinates flower opening, pollen maturation, and gynoecium function in tomato.
植物将花朵开放的时间与花粉和雌蕊成熟时间进行协调，以实现成功授粉。然而，对于这种协调是如何执行的，我们却知之甚少。我们发现，在一种茉莉酸（JA）不敏感的番茄突变体jai1-1中，花芽发育在花朵开放前立即暂停。对花芽中的植物激素测量和RNA分析表明，新合成的JA在花朵开放前两天达到峰值，并且转录因子基因SlMYB21在jai1-1中的表达延迟。表达人工阻遏物AtMYB24-SRDX的转基因番茄植株的芽，预计会阻碍SlMYB21的功能，其花朵开放中止，与jai1-1的芽相似。此外，AtMYB24-SRDX植株产生了发芽能力不足的异常花粉粒以及不支持花粉管伸长的雌蕊。我们得出结论，JA促进了SlMYB21的表达，而SlMYB21协调了番茄的花朵开放、花粉成熟和雌蕊功能。
