Potassium enhances the sugar assimilation in leaves and fruit by regulating the expression of key genes involved in sugar metabolism of Asian pears

摘要

AbstractPotassium (K) plays an important role in fruit quality, and is well known as the most important quality element. A field experiment was conducted with four K levels of 0 (control), 150 (K150), 300 (K300), 450 (K450) kg K2O ha?1in 2014–2015. The aim was to elucidate the roles of K in fruit growth, and the mechanism of K in regulating sugar metabolism between the leaves and fruit of Asian pear (PyrusL.). The results showed that the K concentration and accumulation in leaves and fruit with the net photosynthetic rate and SPAD value of leaves were found to increase with the increase of K application rates. Increasing K application rates also led to promote the effectiveness of accumulation of glucose, fructose, sorbitol, and sucrose in fruit. During the early fruit development stage, the increase of all soluble sugars in leaves was correlated with the up-regulation expression of geneAIVandS6PDH. Furthermore, with fruit development, the expression ofAIV1, SPS1andSUS, S6PDHandSDH3involved in sugar metabolism in leaves were up-regulated by increasing the K application rates, resulting in higher accumulation of soluble sugars in leaves. Interestingly, at the fruit maturity stage the expression ofSUTin leaves, andSPS1, SUSandSUTin fruit was significantly up-regulated, leading to higher sucrose accumulation in fruit. Thus, K-promoted sugar accumulation of the leaves and fruit might result from up-regulated expression levels of key genes involved in sugar metabolism by K in leaves and fruit.]]>