Wang Zhike, Ma Rui, Zhao Mengshi, Wang Fangfang, Zhang Ning, Si Huanjun
College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China.
Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China.
Front Plant Sci. 2020 Apr 8;11:311. doi: 10.3389/fpls.2020.00311. eCollection 2020.
In plants, nitric oxide synthase (NOS)-like or nitrate reductase (NR) produces nitric oxide (NO), which is involved in releasing seed dormancy. However, its mechanism of effect in potato remains unclear. In this study, spraying 40 μM sodium nitroprusside (SNP), an exogenous NO donor, quickly broke tuber dormancy and efficiently promoted tuber sprouting, whereas 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), an NO scavenger, repressed the influence of NO on tuber sprouting. Compared with the control (distilled water), SNP treatment led to a rapid increase in NO content after 6 h and a decreased abscisic acid (ABA) content at 12 and 24 h. c-PTIO treatment significantly inhibited increase of NO levels and increased ABA production. In addition, N -nitro-L-arginine methyl ester, an NOS inhibitor, clearly inhibited the NOS-like activity, whereas tungstate, an NR inhibitor, inhibited the NR activity. Furthermore, NO promoted the expression of a gene involved in ABA catabolism (, encoding ABA 8'-hydroxylase) and inhibited the expression of a gene involved in ABA biosynthesis (, encoding 9--epoxycarotenoid dioxygenase), thereby decreasing the ABA content, disrupting the balance between ABA and gibberellin acid (GA), and ultimately inducing dormancy release and tuber sprouting. The results demonstrated that NOS-like or NR-generated NO controlled potato tuber dormancy release and sprouting via ABA metabolism and signaling in tuber buds.
在植物中，一氧化氮合酶（NOS）样蛋白或硝酸还原酶（NR）产生一氧化氮（NO），其参与解除种子休眠。然而，其在马铃薯中的作用机制仍不清楚。在本研究中，喷施40 μM硝普钠（SNP，一种外源NO供体）可迅速打破块茎休眠并有效促进块茎发芽，而NO清除剂2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物（c-PTIO）可抑制NO对块茎发芽的影响。与对照（蒸馏水）相比，SNP处理6小时后NO含量迅速增加，12小时和24小时时脱落酸（ABA）含量降低。c-PTIO处理显著抑制NO水平的升高并增加ABA的产生。此外，NOS抑制剂N-硝基-L-精氨酸甲酯明显抑制NOS样活性，而NR抑制剂钨酸盐抑制NR活性。此外，NO促进参与ABA分解代谢的基因（编码ABA 8'-羟化酶）的表达，并抑制参与ABA生物合成的基因（编码9-顺式环氧类胡萝卜素双加氧酶）的表达，从而降低ABA含量，破坏ABA与赤霉素（GA）之间的平衡，并最终诱导休眠解除和块茎发芽。结果表明，NOS样蛋白或NR产生的NO通过块茎芽中的ABA代谢和信号传导控制马铃薯块茎的休眠解除和发芽。
