State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Cooperative Innovation Center of Technology and Material of Water Treatment, Jiangnan University, Wuxi, 214122, China.
Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, China.
Chemosphere. 2020 Oct;256:127157. doi: 10.1016/j.chemosphere.2020.127157. Epub 2020 May 22.
Microcystins released by cyanobacteria affect crop growth and productivity, and even food safety. Plant hormones play a vital role in regulating growth, development and stress response in plants. Therefore, we studied the response of hormones including abscisic acid (ABA), indole-3-acetic acid (IAA), Zeatin (ZT) and gibberellin (GA) as well as hormone balances (IAA/ABA, ZT/ABA and GA/ABA) to cyanobacterial extract containing microcystins (1, 10, 100 and 1000 μg/L) during stress and recovery periods. Low concentration microcystins (1 μg/L) promoted growth of rice seedlings by increasing levels of IAA, ZT and GA and maintaining hormone balances. In addition, the up-regulation of OsYUCCA1 increased IAA level in rice roots by promoting IAA biosynthesis. High concentrations microcystins (10, 100 or1000 μg/L) inhibited growth of rice seedlings by reducing levels of IAA, ZT and GA and ratios of IAA/ABA, ZT/ABA and GA/ABA due to increased ABA level. The increase in ABA in rice seedlings induced by high concentrations MCs was resulted from up-regulation of OsNCED1, OsNCED3, OsNCED4 and OsZEP to enhance ABA biosynthesis, and was controlled by up-regulating expression levels of OsABAox1-3 for enhancing ABA catabolism as negative feedback. The highest concentration of MCs (1000 μg/L) caused irreversible damage to metabolisms of IAA and ABA, partly resulting in unrecoverable inhibition on rice growth. All results demonstrate that "low-concentration promotion and high-concentration inhibition" of microcystins was associated with changes in hormone levels and balances by affecting their metabolisms, and could be helpful for guiding agricultural irrigation with microcystin contaminated water.
微囊藻毒素会影响作物的生长和生产力，甚至食品安全。植物激素在植物的生长、发育和应激反应中起着至关重要的作用。因此，我们研究了包括脱落酸（ABA）、吲哚-3-乙酸（IAA）、玉米素（ZT）和赤霉素（GA）在内的激素以及激素平衡（IAA/ABA、ZT/ABA 和 GA/ABA）对含有微囊藻毒素（1、10、100 和 1000μg/L）的蓝藻提取物的应激和恢复期的反应。低浓度的微囊藻毒素（1μg/L）通过增加 IAA、ZT 和 GA 的水平并维持激素平衡来促进水稻幼苗的生长。此外，OsYUCCA1 的上调通过促进 IAA 生物合成增加了水稻根系中的 IAA 水平。高浓度的微囊藻毒素（10、100 或 1000μg/L）通过降低 IAA、ZT 和 GA 的水平以及 IAA/ABA、ZT/ABA 和 GA/ABA 的比例来抑制水稻幼苗的生长，这是由于 ABA 水平的增加。高浓度 MCs 诱导的水稻幼苗中 ABA 的增加是由于 OsNCED1、OsNCED3、OsNCED4 和 OsZEP 的上调增强了 ABA 的生物合成，并且通过上调 OsABAox1-3 的表达水平来增强 ABA 分解代谢来进行负反馈控制。最高浓度的 MCs（1000μg/L）对 IAA 和 ABA 的代谢造成了不可逆的损害，部分导致对水稻生长的不可恢复的抑制。所有结果表明，微囊藻毒素的“低浓度促进和高浓度抑制”与通过影响其代谢来改变激素水平和平衡有关，并有助于指导农业灌溉用含有微囊藻毒素的水。
