RESUMEN
Reactive oxygen species (ROS) have been extensively suggested to stimulate ethylene production. However, the molecular mechanism by which ROS stimulate ethylene production remains largely unclear. Here, transcriptome profiling was used to verify if ROS could stimulate ethylene production via direct formation of ethylene from ROS. Trichloroisocyanuric acid (TCICA) can stimulate seed germination in rice. When transcriptome profiling was performed to determine the molecular responsiveness of rice seeds to TCICA, TCICA was initially proven to be a ROS-generating reagent. A total of 300 genes potentially responsive to TCICA treatment were significantly annotated to cysteine, and the expression of these genes was significantly upregulated. Nonetheless, the levels of cystine did not exhibit significant changes upon TCICA exposure. Cystine was then proven to be a substrate that reacted with TCICA to form ethylene under FeSO4 conditions. Moreover, 7 of 22 genes responsive to TCICA were common with the hydrogen peroxide (H2O2)-responsive genes. Ethylene was then proven to be produced from cysteine or cystine by reacting with H2O2 under FeSO4 condition, and the hydroxyl radical (OH-) was proposed to be the free radical species responsible for ethylene formation under FeSO4 condition. These results provide the first line of evidence that ethylene can be produced from ROS in a non-enzymatic manner, thereby unveiling one new molecular mechanism by which ROS stimulate ethylene production and offering novel insights into the crosstalk between ethylene and ROS.
Asunto(s)
Etilenos , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Oryza , Especies Reactivas de Oxígeno , Semillas , Especies Reactivas de Oxígeno/metabolismo , Oryza/genética , Oryza/metabolismo , Oryza/efectos de los fármacos , Semillas/efectos de los fármacos , Semillas/genética , Semillas/metabolismo , Etilenos/metabolismo , Etilenos/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Germinación/efectos de los fármacos , Peróxido de Hidrógeno/metabolismo , Transcriptoma/efectos de los fármacos , Transcriptoma/genética , Triazinas/farmacologíaRESUMEN
KEY MESSAGE: Ethylene formation via methionine reacting with trichloroisocyanuric acid under FeSO4 condition in a non-enzymatical manner provides one economically and efficiently novel ethylene-forming approach in planta. Rice seed germination can be stimulated by trichloroisocyanuric acid (TCICA). However, the molecular basis of TCICA in stimulating rice seed germination remains unclear. In this study, the molecular mechanism on how TCICA stimulated rice seed germination was examined via comparative transcriptome. Results showed that clustering of transcripts of TCICA-treated seeds, water-treated seeds, and dry seeds was clearly separated. Twenty-two and three hundred differentially expressed genes were identified as TCICA treatment responsive genes and TCICA treatment potentially responsive genes, respectively. Two and one TCICA treatment responsive genes were involved in ethylene signal transduction and iron homeostasis, respectively. Seventeen of the three hundred TCICA treatment potentially responsive genes were significantly annotated to iron ion binding. Meanwhile, level of methionine (ethylene precursor) showed a 73.9% decrease in response to TCICA treatment. Ethylene was then proved to produce via methionine reacting with TCICA under FeSO4 condition in vitro. Revealing ethylene formation by TCICA not only may bring novel insights into crosstalk between ethylene and other phytohormones during rice seed germination, but also may provide one economically and efficiently novel approach to producing ethylene in planta independently of the ethylene biosynthesis in plants and thereby may broaden its applications in investigational and applied purposes.
