Abstract
BackgroundAbscisic acid (ABA) and sucrose act as molecular signals in response to abiotic stress. However, how their synergy regulates the source-sink relationship has rarely been studied. This study aimed to reveal the mechanism underlying the synergy between ABA and sucrose on assimilates allocation to improve grain yield and quality of rice. The early indica rice cultivar Zhefu802 was selected and planted in an artificial climate chamber at 32/24 °C (day/night) under natural sunlight conditions. Sucrose and ABA were exogenously sprayed (either alone or in combination) onto rice plants at flowering and 10 days after flowering.ResultsABA plus sucrose significantly improved both the grain yield and quality of rice, which was mainly a result of the higher proportion of dry matter accumulation and non-structural carbohydrates in panicles. These results were mainly ascribed to the large improvement in sucrose transport in the sheath-stems in response to the ABA plus sucrose treatment. In this process, ABA plus sucrose significantly enhanced the contents of starch, gibberellic acids, and zeatin ribosides as well as the activities and gene expression of enzymes involved in starch synthesis in grains. Additionally, remarkable increases in trehalose content and expression levels of trehalose-6-phosphate synthase1, trehalose-6-phosphate phosphatase7, and sucrose non-fermenting related protein kinase 1A were also found in grains treated with ABA plus sucrose.ConclusionThe synergy between ABA and sucrose increased grain yield and quality by improving the source-sink relationship through sucrose and trehalose metabolism in grains.
Highlights
Abscisic acid (ABA) and sucrose act as molecular signals in response to abiotic stress
Effect of abscisic acid (ABA) and sucrose on grain yield and rice quality Rice plants exogenously sprayed with low sucrose concentrations attained higher grain yields than the control, for the treatments with 0.5% sucrose, which achieved a 13.5% increase in grain yield compared to the control (Additional file 1: Figure S1)
No significant differences were found in grain yield between the control and the ABA or sucrose alone treatments, but about 10.3 and 7.8% increases were found in rice plants treated with sucrose and ABA, respectively, compared to the control (Fig. 1a)
Summary
Abscisic acid (ABA) and sucrose act as molecular signals in response to abiotic stress. In response to high temperature conditions, ABA increases the concentrations of soluble sugar, starch, and non-structural carbohydrate (NSC), enhances gene expression of heat shock proteins and proteins participating in sugar transport and conversion, and improves the activities of antioxidases and adenosine triphosphate content in rice plant spikelets [10]. These results suggest that exogenous application of ABA could enhance sucrose transport and accelerate sucroseto-starch conversion, safeguarding carbohydrate metabolism and energy homeostasis against external stress [10]. A possible interaction may exist between sucrose and ABA in mediating the activity and expression of SUS during the grain filling stage in rice [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
