Apple Research Institute, National Institute of Horticultural and Herbal Science, Rural Development Administration, Gunwi 39000, Korea.
Postharvest Technology Division, National Institute of Horticultural and Herbal Science, Rural Development Administration, Wanju 55365, Korea.
Int J Mol Sci. 2022 May 31;23(11):6153. doi: 10.3390/ijms23116153.
The coloration of the apple fruit ( Borkh.) depends on pigment content. Light stimulus activates a broad range of photosynthesis-related genes, including carotenoids. The effect of light on two red commercial apple cultivars, 'Summer Prince' and 'Arisoo' at the juvenile stage were examined. Apple fruits were either bagged to reduce light irradiation or were exposed to direct, enhanced sunlight (reflected). The pigment content and the expression of carotenoid metabolism genes in the peel and flesh of apple fruits were significantly different between the shaded and the reflected parts. These parameters were also different in the two cultivars, highlighting the contribution of the genetic background. Further, a combination of light and transient overexpression of carotenogenic genes increased fruit coloration and pigment content in the variety 'RubyS'. Western blot analysis showed the expression of small heat shock proteins (smHSP) in lysates extracted from the reflected part of the fruits but not in the bagged fruits, indicating the activation of smHSP in response to heat generated by the reflected light. Therefore, the synergy between the genes and the environment dictates the color of apple fruits.
苹果果实的颜色（Borkh.）取决于色素含量。光刺激激活了广泛的与光合作用相关的基因，包括类胡萝卜素。本研究以幼年阶段的两个红色商业苹果品种“Summer Prince”和“Arisoo”为试材，研究了光对其的影响。苹果果实要么套袋以减少光照，要么暴露于直接增强的阳光下（反射光）。苹果果实果皮和果肉中的色素含量和类胡萝卜素代谢基因的表达在遮荫和反射部分之间存在显著差异。这两个品种的这些参数也不同，突出了遗传背景的贡献。此外，光和类胡萝卜素生物合成基因的瞬时过表达的组合增加了品种“RubyS”的果实着色和色素含量。Western blot 分析显示，从小果反射部分提取的裂解物中表达了小分子热激蛋白（smHSP），但在套袋果实中没有表达，表明 smHSP 对反射光产生的热量的响应而被激活。因此，基因与环境的协同作用决定了苹果果实的颜色。
