Post-anthesis saline-alkali stress inhibits grain filling by promoting ethylene production and signal transduction

Yaqiong Peng, Yinke Chen, Youming Yuan, Bohan Liu, Peng Yu, Shihao Song, Yake Yi, Zhenning Teng, Zhenxie Yi, Jianhua Zhang, Shuan Meng*, Nenghui Ye*, Meijuan Duan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Saline-alkali stress is one of the major abiotic stresses that severely affect rice yield. However, the mechanism by which saline-alkali stress regulates grain filling in rice is still unclear. In this study, Oryza sativa L. spp. Indica cultivar Chaoyou1000 (C1000) was exposed to post-anthesis saline-alkali conditions at 6 days after anthesis, which significantly reduced the grain weight by suppressing the accumulation of starch and non-structural carbohydrates in grains. Further analysis found that 1-aminocyclopropane-1-carboxylate (ACC), a precursor for ethylene, was increased by saline-alkali treatment. qRT-PCR results showed that several key genes involved in ethylene biosynthesis, including the OsACS and OsACO genes, were upregulated in saline-alkali-treated grains. In addition, genes involved in the ethylene signalling pathway were also induced by saline-alkali stress. Exogenous ethylene application reduced grain weight and both starch and NSC contents in grains of C1000, suggesting that saline-alkali-induced ethylene has a negative effect on grain filling. Furthermore, the gene expression levels of OsSUS, OsAGPL, OsAGPS, OsSSI and OsSSIIIa, which are key genes in the starch biosynthesis pathway, were downregulated in saline-alkali-treated grains. In agreement, assays on these enzymes further revealed that saline-alkali stress decreased the activities of sucrose synthase (SUS), adenosine diphosphate glucose pyrophosphorylase (AGP) and starch synthase (StS). Together, our results indicated that saline-alkali stress suppressed the enzyme activities involved in the conversion of sucrose to starch by elevating ethylene production, which led to inhibition of grain filling.

Original languageEnglish
Article numbere384
Number of pages14
JournalFood and Energy Security
DOIs
Publication statusE-pub ahead of print - 15 May 2022

Scopus Subject Areas

  • Forestry
  • Food Science
  • Renewable Energy, Sustainability and the Environment
  • Agronomy and Crop Science

User-Defined Keywords

  • ethylene
  • grain filling
  • rice
  • Saline-alkali stress
  • starch accumulation

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