NO and ABA Interaction Regulates Tuber Dormancy and Sprouting in Potato.

Zhike Wang,Rui Ma,Huanjun Si,Mengshi Zhao,Ning Zhang,Fangfang Wang

doi:10.3389/fpls.2020.00311

Zhike Wang, Rui Ma + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2020.00311

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Abstract

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, NG-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 (StCYP707A1, encoding ABA 8′-hydroxylase) and inhibited the expression of a gene involved in ABA biosynthesis (StNCED1, encoding 9-cis-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.

Highlights

The potato (Solanum tuberosum L.) is an important food crop and industrial raw material
The tubers sprayed with 40 μM sodium nitroprusside (SNP) had a sprouting rate of 56.23% at 20 days after treatment, whereas the c-PTIO–treated tubers had a sprouting rate of 3.04%, and the control group sprayed with distilled water (DW) had a sprouting rate of inhibitor treatment were analyzed via Quantitative reverse transcriptase–polymerase chain reaction (qRT-PCR)
SNP treatment significantly decreased the expression of StNCED1 compared with the control. These results demonstrated that nitric oxide (NO) promoted the expression of abscisic acid (ABA) catabolism gene (StCYP707A1) and inhibited the expression of ABA biosynthesis gene (StNCED1)

Summary

Introduction

The potato (Solanum tuberosum L.) is an important food crop and industrial raw material. The dormancy and sprouting of potato tubers are very significant for potato cultivation, tuber production, and industrial processing (Aksenova et al, 2013). When tubers are used as food or raw materials for processing, NO and ABA Regulates Dormancy a long dormancy period is essential for transportation and storage, and dormancy release results in a large consumption of water and nutrients, decreasing commodity quality and value (Aksenova et al, 2013). Tuber dormancy was regulated by a variety of factors and was dependent on plant hormones (Suttle et al, 2012; Sonnewald and Sonnewald, 2014), genetic factors, tuber variety, storage temperature and conditions, and particular signaling molecules, such as nitric oxide (NO) (Noritake et al, 1996) and reactive oxygen species (ROS) (Peivastegan et al, 2019). The balance between abscisic acid (ABA) and gibberellin acid (GA) is a major regulator of the dormancy state, in which GA promotes the progression from breaking to sprouting (Wróbel et al, 2017)

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