Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants
Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants
复制标题
增加蔗糖积累通过促进拟南芥植物中的生长素信号传导来调节缺铁反应
DOI：
10.1104/pp.15.01598
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发表时间：
2016-02-01
期刊：
影响因子：
7.4
通讯作者：
Zheng, Shao Jian
中科院分区：
文献类型：
--
作者：
Lin, Xian Yong;Ye, Yi Quan;Zheng, Shao Jian
以前的研究已经确定生长素在调控根系缺铁反应中作用于一氧化氮的上游，但生长素的上游信号分子尚不清楚。在本研究中，我们发现缺铁增加了拟南芥（Arabidopsis thaliana）根系中的蔗糖（Suc）水平。外源施加Suc进一步刺激铁缺乏诱导的铁螯合还原酶（FCR）活性和铁获取相关基因FRO2、IRT1和FIT的表达。在黑暗处理中观察到相反的模式。此外，在缺铁条件下，高富集转基因植株35S::SUC2的FCR活性和铁获取相关基因的表达量高于野生型植株，而低富集突变体SUC2 -5的FCR活性和铁获取相关基因的表达量低于野生型植株。因此，在35S::SUC2中，铁缺乏耐受性增强，而在SUC2 -5中则减弱。生长素诱导的DR5-GUS转基因植株在缺铁条件下，外源Suc也增加了根β -葡萄糖醛酸酶（GUS）活性。然而，在生长素运输受损的突变体aux1-7和pin1-1中，以及在缺铁条件下使用生长素运输抑制剂处理的野生型植物中，外源的Suc未能增加FCR活性和铁获取相关基因的表达。综上所述，研究人员发现，植物的缺铁反应需要增加硫的积累，生长素在下游传递缺铁信号。
Previous studies have identified that auxins acts upstream of nitric oxide in regulating iron deficiency responses in roots, but the upstream signaling molecule of auxins remains unknown. In this study, we showed that Fe deficiency increased sucrose (Suc) level in roots of Arabidopsis (Arabidopsis thaliana). Exogenous application of Suc further stimulated Fe deficiency-induced ferric-chelate-reductase (FCR) activity and expression of Fe acquisition-related genes FRO2, IRT1, and FIT in roots. The opposite patterns were observed in the dark treatment. In addition, FCR activity and expression of Fe acquisition-related genes were higher in the Suc high-accumulating transgenic plant 35S::SUC2 but were lower in the Suc low-accumulating mutant suc2-5 compared with wild-type plants under Fe-deficient conditions. Consequently, Fe deficiency tolerance was enhanced in 35S::SUC2 but was compromised in suc2-5. Exogenous Suc also increased root beta-glucuronidase (GUS) activity in auxin-inducible reporter DR5-GUS transgenic plants under Fe deficiency. However, exogenous Suc failed to increase FCR activity and expression of Fe acquisition-related genes in the auxin transport-impaired mutants aux1-7 and pin1-1 as well as in the wild-type plants treated with an auxin transport inhibitor under Fe deficiency. In summary, we found that increased Suc accumulation is required for regulating Fe deficiency responses in plants, with auxins acting downstream in transmitting the Fe deficiency signal.