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

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 r esults showed that several key genes involved in ethylene biosynthesis, including theOsACS andOsACO 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 ofOsSUS,OsAGPL,OsAGPS,OsSSI andOsSSIIIa, 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 filli...
Source: Food and Energy Security - Category: Food Science Authors: Tags: ORIGINAL ARTICLE Source Type: research