Spermidine Increases the Sucrose Content in Inferior Grain of Wheat and Thereby Promotes Its Grain Filling

Abstract

The improvement of grain filling is the key issue for promoting wheat thousand grain weight and grain yield. The levels of polyamines (PAs) significantly affect grain filling in cereals, but the mechanism by which PAs affect grain filling in wheat is unclear. In the present study, six wheat cultivars whose grain filling differed were used, and their grain-filling characteristics and endogenous PA contents were measured. In addition, exogenous PAs were supplied during the wheat grain-filling period. The grain-filling characteristics, hormone levels, starch contents, and gene expression [based on RNA sequencing (RNA-seq)] in the grain were analyzed. The objective of the present study was to investigate the effects of PAs on grain filling in wheat. The results suggested that the direct synthetic pathway from putrescine (Put) to spermidine (Spd) in the grain was a key factor in promoting grain filling and thousand grain weight in wheat. Spd through regulates the grain-filling rate of inferior grain during the early grain-filling period to affecting the grain filling and thousand grain weight of wheat. The promotive effect of Spd on the grain filling of inferior wheat grain was notably related to carbohydrate metabolism in that grain. Spd significantly increased the zeatin (Z) + zeatin riboside (ZR) contents but reduced the ethylene (ETH) evolution rate in the inferior grain. In addition, Spd significantly increased the sucrose synthase (SS) and acid invertase (AI) activities in the inferior grain. These effects of Spd led to increased sucrose content in the inferior grain. These reasons might explain why Spd significantly promoted the filling and weight of inferior wheat grain.

Asterarcys Quadricellulare Triggers Bioactive Amines Promoting Sugarcane Sprout and Growth

“…Meanwhile, the Spm in the culms (Table 2) from propagules applied by AQ250 was higher, in contrast to the result in the own propagule tissue (Table 1). Changes can occur in the PAs pro le with modi cations in glucose metabolism and carbon/nitrogen (C/N) signaling pathways (Anwar et al 2015), and Spd is also capable of improving the ow from the source to the drain and the transport of sugars (Luo et al 2019).…”

Strengthening leaf physiological functioning and grain yield formation in heat-stressed wheat through potassium application

“…The increase in grain numbers could be associated with restricted ethylene production, which reduced the abscission of peduncles and abortion of newly developed grains in spikelets ( Ruan et al, 2012 ; Ali et al, 2017 ). Exogenous application of K in wheat at post-anthesis could improve the stay green character associated with synthesizing cytokinin and carbohydrates ( Luo et al, 2019 ). Applying K in wheat under abiotic stress has increased the stay green character by reducing oxidative stress ( Beaton and Sekhon, 1985 ).…”

Exogenously Applied Spermidine Alleviates Hypoxia Stress in Phyllostachys Praecox Seedlings Via Changes in Endogenous Hormones and Gene Expression

“…Under water-de cient conditions, the endogenous ABA content from roots to leaves increased and induced stomatal closure (Matías et al 2015). On the other hand, Luo et al (2019) suggested that the promoting effect of external Spd on grain lling of wheat was signi cantly related to the increasing concentration of ABA in grains. The ABA response to ooding may differ and depend on the plant species and duration of ooding.…”